Photoshop How To Use: rec.photo.digital - 26 new messages in 9 topics

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Today's topics:

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TOPIC: How hold compact on chest? (See what wearer does)
http://groups.google.com/group/rec.photo.digital/t/bae5b502c2a992fd?hl=en
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== 1 of 2 ==
Date: Wed, May 6 2009 11:21 pm
From: Paul Furman

ASAAR wrote:
> On Fri, 17 Apr 2009 11:00:54 +0100, Sandi wrote:
>
>> C'mon guys. I need some ideas!!!! I'm struggling to see this
>> one. :-)
>>
>> The helmetcams look great but sadly they are way beyond my
>> budget! They also seem to need another camera as I can't easily
>> see how I would mount a compact camera on such a helmet unless
>> there was some additional special bracket.
>
> Sandi, B&H has quite a number of stabilizing gadgets, some of
> which could be what you're looking for, but as you fear, many tend
> to be quite expensive. At least you can sort by price, and if you
> search starting from the low price end you may never reach the
> Glidecam stabilizer that goes for $22,899.95. :) There's a $29.95
> Stedi-Stock shoulder brace that resembles a rifle stock, but it
> doesn't seem to be designed for someone walking about. At $44.95
> Video Innovators S-800 Standard Shoulder Support might help, but I
> have no experience with these things. Some of them, such as various
> Steadicam models just mount the camera in the center of a large
> contraption so that it's balanced, and I suppose helps to stabilize
> the camera similar to the way tightrope walkers use their long
> horizontal bars, and also because now much of the mass is now at the
> periphery, not at the center where the small camera lives,
> increasing its "moment arm" which helps by requiring more torque to
> produce a given amount of twisting or rotation. These gadgets can
> add quite a bit of weight, and all of that extra mass also helps to
> reduce the camera's jiggling.
>
> Glidecam also has a much more modest stabilizer designed for small
> cameras, more than $22,500 cheaper than the model mentioned above.
> At $349.95 it may still be out of your price range, but take a look
> at its picture - it may give you some ideas.
>
>
> http://www.bhphotovideo.com/c/product/579906-REG/Glidecam_HD_1000_HD1000_Stabilizer_System.html#features
>
> I'd also suggest taking a look at B&H's Pro Video Tripods & Support
> page, which has links to their "Hand Held & Shoulder Stabilizers"
> and "Stabilizer Systems" sections.
>
>
> http://www.bhphotovideo.com/c/category/8311/Carrying_Support_Pro_Video_Tripods_Support.html
>
>
>> I also muse around the idea that there might an arrangement
>> which uses a belt or garment worn around the chest or shoulders
>> and which can support the camera at the front IYSWIM. The camera
>> might then be about 6 inches below the neck. But I can't quite
>> see how this might work without the camera bouncing a lot and
>> I'd hoped someone here had tried some solution to this.
>
> You'll find products like that at B&H's website, some having wide
> padded belts that go around the waist and shoulders, supporting the
> stabilizer systems, taking the lifting burden away from the hands,
> allowing them to guide the camera. All of these are shown and
> described in detail in B&H's Professional Video SourceBook, Volume
> 1, and you should be able to order it at no charge from the website.
>
> And if you have an extra free moment or two . . .
>
> http://en.wikipedia.org/wiki/Torque

There's got to be a free way to implement this. Just mount the camera to
a tightrope walker's pole if nothing else.

--
Paul Furman
www.edgehill.net
www.baynatives.com

all google groups messages filtered due to spam

== 2 of 2 ==
Date: Thurs, May 7 2009 3:16 am
From: ASAAR

On Wed, 06 May 2009 23:21:26 -0700, Paul Furman wrote:

>> http://en.wikipedia.org/wiki/Torque
>
> There's got to be a free way to implement this. Just mount the camera to
> a tightrope walker's pole if nothing else.

Even if you could get a tightrope walker's pole for nothing, it
would be hell on taking indoor portraits. And then there are all of
those shots papparazzis would miss trying to chase their prey down
alleys!

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TOPIC: Scenic areas in England
http://groups.google.com/group/rec.photo.digital/t/1076be556766c491?hl=en
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== 1 of 4 ==
Date: Thurs, May 7 2009 1:04 am
From: Chris H

In message <4a0279f4$0$11195$c30e37c6@pit-reader.telstra.net>, Paul
Bartram <paul.bartram@AT.OR.invalid> writes
>
>"Chris H" <chris@phaedsys.org> wrote
>
>> You mean there was terrorism before 9/11/2001?
>
>I was nearby when an IRA car bomb

Is that a Branch of Al-qeada? (All terrorists ultimately belong to Al-
Queda.)

>went off outside The Old Bailey in central
>London - it rattled the windows of our building nearly a mile away. That was
>1973.
>http://prints.paphotos.com/pictures_675862/OLD-BAILEY-BOMB-LONDON-1973.html

Ironically this was about the time when the USA were not only permitting
NORAID to fund these terrorists but also funding anti-Russian Islamic
groups like the Taliban and Al-Qeada.... despite SIS and SAS warnings
that it would backfire on the west.

>I vividly remember the green-tinted gouges in the sandstone wall of the
>court building (the car was green) and -as you can see in the photo on that
>page - ALL the windows on the office block opposite were blown out, even the
>ones on the other side. Casualties were light because the police had a
>warning, and were able to evacuate the area.

I recall a day in London where there were 4 bomb alerts in one day. I
forget how many were real. I think only one went off and the others
were dismantled.

--
\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
\/\/\/\/\ Chris Hills Staffs England /\/\/\/\/
\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/

== 2 of 4 ==
Date: Thurs, May 7 2009 6:30 am
From: Mike Lane

Chris Malcolm wrote on May 7, 2009:

> In rec.photo.digital John McWilliams <jpmcw@comcast.net> wrote:
>> Chris Malcolm wrote:
>>> In rec.photo.digital John McWilliams <jpmcw@comcast.net> wrote:
>>>> I am curious as to what might constitute founded paranoia! Can you give
>>>> an example or two?
>>>
>>> Martin Luther King thinking assassins were plotting to kill him.
>
>> I submit, then, that that's not paranoia.
>
> Ah! So like most psychiatrists, your diagnosis of paranoia can change
> when the state of mind does not change but the world changes. I find
> that a very unsatisfactory definition, despite its popularity. It
> means that a secure diagnosis requires not only a psychiatrist but a
> detective.
>
Surely the term 'paranoia' implies that the belief is irrational and has no
foundation in reality. A totally rational belief based on evidence, that
people are trying to kill you, cannot be regarded as paranoia. Can it?

--
Mike Lane
UK North Yorkshire

== 3 of 4 ==
Date: Thurs, May 7 2009 7:02 am
From: Chris H

In message <0001HW.C628A0F5000B0891B01AD9AF@news.virginmedia.com>, Mike
Lane <invalid@mac.com> writes
>Chris Malcolm wrote on May 7, 2009:
>
>> In rec.photo.digital John McWilliams <jpmcw@comcast.net> wrote:
>>> Chris Malcolm wrote:
>>>> In rec.photo.digital John McWilliams <jpmcw@comcast.net> wrote:
>>>>> I am curious as to what might constitute founded paranoia! Can you give
>>>>> an example or two?
>>>>
>>>> Martin Luther King thinking assassins were plotting to kill him.
>>
>>> I submit, then, that that's not paranoia.
>>
>> Ah! So like most psychiatrists, your diagnosis of paranoia can change
>> when the state of mind does not change but the world changes. I find
>> that a very unsatisfactory definition, despite its popularity. It
>> means that a secure diagnosis requires not only a psychiatrist but a
>> detective.
>>
>Surely the term 'paranoia' implies that the belief is irrational and has no
>foundation in reality.

Yes.

> A totally rational belief based on evidence, that
>people are trying to kill you, cannot be regarded as paranoia. Can it?

Yes.

To the paranoid whilst no one is out to get them they can create
"rational" evidence that some one is. Define "rational".... (and
"reasonable" whilst you are at it. I have had experience of this with
some one who is bi-polar.

People who really are being stalked when presenting real factual
evidence can sound paranoid and may not be believed.

A paranoid person may, based on some irrational evidence, think people
are out to kill them when in fact people are out to kill them but for a
different completely rational set of motives.

What the target feels and believes is very different to what the killer
feels and believes.

This can also be very different to
a What the government/establishment feels and believes
b What the government/establisment tells the public.

A and b may be mutually exclusive points of view.

--
\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
\/\/\/\/\ Chris Hills Staffs England /\/\/\/\/
\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/

== 4 of 4 ==
Date: Thurs, May 7 2009 7:13 am
From: John McWilliams

Chris H wrote:
> In message <0001HW.C628A0F5000B0891B01AD9AF@news.virginmedia.com>, Mike
> Lane <invalid@mac.com> writes
>> Chris Malcolm wrote on May 7, 2009:
>>
>>> In rec.photo.digital John McWilliams <jpmcw@comcast.net> wrote:
>>>> Chris Malcolm wrote:
>>>>> In rec.photo.digital John McWilliams <jpmcw@comcast.net> wrote:
>>>>>> I am curious as to what might constitute founded paranoia! Can you give
>>>>>> an example or two?
>>>>> Martin Luther King thinking assassins were plotting to kill him.
>>>> I submit, then, that that's not paranoia.
>>> Ah! So like most psychiatrists, your diagnosis of paranoia can change
>>> when the state of mind does not change but the world changes. I find
>>> that a very unsatisfactory definition, despite its popularity. It
>>> means that a secure diagnosis requires not only a psychiatrist but a
>>> detective.
>>>
>> Surely the term 'paranoia' implies that the belief is irrational and has no
>> foundation in reality.
>
> Yes.
>
>> A totally rational belief based on evidence, that
>> people are trying to kill you, cannot be regarded as paranoia. Can it?
>
> Yes.
>
> To the paranoid whilst no one is out to get them they can create
> "rational" evidence that some one is. Define "rational".... (and
> "reasonable" whilst you are at it. I have had experience of this with
> some one who is bi-polar.
>
> People who really are being stalked when presenting real factual
> evidence can sound paranoid and may not be believed.
>
> A paranoid person may, based on some irrational evidence, think people
> are out to kill them when in fact people are out to kill them but for a
> different completely rational set of motives.
>
> What the target feels and believes is very different to what the killer
> feels and believes.
>
> This can also be very different to
> a What the government/establishment feels and believes
> b What the government/establisment tells the public.
>
> A and b may be mutually exclusive points of view.

In short, you're admitting that the example of Dr. King being paranoid
was wrong.

--
lsmft

==============================================================================
TOPIC: How can I improve my shoots?
http://groups.google.com/group/rec.photo.digital/t/20f68722a0441cc5?hl=en
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== 1 of 4 ==
Date: Thurs, May 7 2009 2:56 am
From: snapper@mailinator.com

On Wed, 6 May 2009 17:40:03 +0200 (CEST), Nomen Nescio <nobody@dizum.com> wrote:

> http://www.flickr.com/photos/colleenm/3304843379/
>
> I am beginning to think I should give up on photography and just accept the job offered by Flicker

Try this for a sunrise:-

http://img147.imageshack.us/my.php?image=s20070306082428aazn8.jpg

== 2 of 4 ==
Date: Thurs, May 7 2009 3:43 am
From: "Atheist Chaplain"

<snapper@mailinator.com> wrote in message
news:12c5059l1sm0486sbted15kif2iipv7u6d@4ax.com...
> On Wed, 6 May 2009 17:40:03 +0200 (CEST), Nomen Nescio
> <nobody@dizum.com> wrote:
>
>> http://www.flickr.com/photos/colleenm/3304843379/
>>
>> I am beginning to think I should give up on photography and just accept
>> the job offered by Flicker
>
> Try this for a sunrise:-
>
> http://img147.imageshack.us/my.php?image=s20070306082428aazn8.jpg
>

hmmm "flickr" rhymes with "arse licker"
the site where everybody will leave a nice comment for you, and expect the
same in return.
some people regard very ordinary photo's as "Remarkable" and "Gorgeous" and
"Fantastic"

--
[This comment is no longer available due to a copyright claim by Church of
Scientology International]
"I like your Christ. I do not like your Christians. They are so unlike your
Christ." Gandhi

== 3 of 4 ==
Date: Thurs, May 7 2009 4:55 am
From: M-M

In article <4a02bb57$1@news.x-privat.org>,
"Atheist Chaplain" <abused@cia.gov> wrote:

> very ordinary photo's

To be extraordinary you need something to be happening in the photo. You
can't just take a picture of an object and expect it to be a great
photo.

You need 3 things: foreground, background and something else added in. A
sunset doesn't cut it. It could be a great background though.

--
m-m
http://www.mhmyers.com

== 4 of 4 ==
Date: Thurs, May 7 2009 5:55 am
From: Chris Malcolm

Atheist Chaplain <abused@cia.gov> wrote:
> <snapper@mailinator.com> wrote in message
> news:12c5059l1sm0486sbted15kif2iipv7u6d@4ax.com...
>> On Wed, 6 May 2009 17:40:03 +0200 (CEST), Nomen Nescio
>> <nobody@dizum.com> wrote:
>>
>>> http://www.flickr.com/photos/colleenm/3304843379/
>>>
>>> I am beginning to think I should give up on photography and just accept
>>> the job offered by Flicker
>>
>> Try this for a sunrise:-
>>
>> http://img147.imageshack.us/my.php?image=s20070306082428aazn8.jpg
>>

> hmmm "flickr" rhymes with "arse licker"
> the site where everybody will leave a nice comment for you, and expect the
> same in return.
> some people regard very ordinary photo's as "Remarkable" and "Gorgeous" and
> "Fantastic"

Flickr as a site doesn't do that. It's the photo pools of certain
specific interest groups which do that. Not surprisingly some have
been set up to maximise the number of gorgeous comments you get to
every photo. Not surprisingly other groups with other purposes avoid
doing that. Not surprisingly some people subscribe to as many
congratulatory groups as they can find.

If that's your experience of Flickr one wonders what you're
doing hanging out in the kind of groups you're sneering at :-)

--
Chris Malcolm

==============================================================================
TOPIC: Reminder: send your puns by May 10th, 2009
http://groups.google.com/group/rec.photo.digital/t/a48b4b5b961ad293?hl=en
==============================================================================

== 1 of 1 ==
Date: Thurs, May 7 2009 3:14 am
From: "Atheist Chaplain"

"Bowser" <up@gone.now> wrote in message
news:49fd9a5c$0$8215$ec3e2dad@news.usenetmonster.com...
> Punography is due on May 10th, 2009. Shoot those visual puns while there's
> still time.
>
> http://www.pbase.com/shootin/gallery/punography
>
> BTW, I was passing by a church last week, and spotted two nuns and a
> priest
> on the steps. I asked them to jump off the bottom step so I could take a
> picture for the mandate. They refused. Shame. No sense of humah.
>
> "Leap of Faith"
>

Bugger, I have been stuck in the big smoke all week on business and
neglected to take a camera (It was supposed to be a day trip but turned into
3 nights and a couple of trips to buy new clothes)
I have a couple of ideas that I will try and get together over the weekend
(advantage of being in the antipodeans, were half a day ahead of the US)

--
[This comment is no longer available due to a copyright claim by Church of
Scientology International]
"I like your Christ. I do not like your Christians. They are so unlike your
Christ." Gandhi

==============================================================================
TOPIC: Telephoto Picture & Technical Analysis
http://groups.google.com/group/rec.photo.digital/t/9003759f40db60ae?hl=en
==============================================================================

== 1 of 6 ==
Date: Thurs, May 7 2009 4:10 am
From: Martin Brown <|||newspam|||@nezumi.demon.co.uk>

Hughes wrote:
> On May 7, 1:39 am, Martin Brown <|||newspam...@nezumi.demon.co.uk>
> wrote:
>> Hughes wrote:
>>> On May 6, 11:05 pm, Martin Brown <|||newspam...@nezumi.demon.co.uk>
>>> wrote:
>>>> Hughes wrote:
>>>>> thread is all about why the Rubinar/MTO can't produce
>>>>> picture like the following:
>>>>> http://www.flickr.com/photos/gps1/1356386350/sizes/l/
>>>> This looks to be an image with a wide angle or standard lens in very
>>>> clear mountain air.
>>>>> Instead, it produces so low contrast (image wide) picture
>>>>> like the following
>>>>> http://www.duliskovich.com/rubinar/Bridge%20%282341%20meters%29%20and...
>>>> My first instinct is that it is suffering from the haze and other muck
>>>> and rubbish floating in the air. Long lenses really need clean air to
>>>> get the best results and I think most of your lost contrast is down to
>>>> that. Good news is that histogram stretching will get a lot of it back.
>>> Why, have you remembered getting a picture in
>>> the MTO with a contrast like the first mountain
>>> picture? It seems that the dynamic range in all
>>> pictures with the Rubinar/MTO are degraded down
>>> to 5 bit from 12 bit.

>> And I expect you would have the same problem with long distance images
>> taken with any telephoto lens of 500mm or longer in less than ideal
>> atmospheric conditions. A faster lens would be easier to focus and might
>> help freeze the seeing but it cannot cut through the haze (IR filters
>> can help for aerial photography if you don't want a colour image).
>
> Do you use Aperture Priority mode or Manual? What's the
> shutter speed you usually use (for instance in the shot you
> shared below)?

EXIF says it was 1/750s at 400ASA equivalent. Lens claims to be 0mm f0.
Everything was manual and on a very chunky tripod. The exposure was
deliberately short to avoid wind vibration. I have put a slice of the
original image up at full sampled resolution - it is visibly soft.

http://www.nezumi.demon.co.uk/temp/slice.jpg

By eye I'd say roughly 2x oversampled looking at the edge transitions.
>
>> One snag of the MTO is that you need full aperture filters which makes
>> it expensive to get a Wratten 87A or equivalent.
>
> Is Wratten 87A supposed to block the heat wave in the infrared?
> It can see thru the haze?

Wratten 87A is a near infrared filter. It blocks all visible light.
Longer wavelengths scatter less than short wavelengths and so the longer
the wavelength you can use the better for hazy days.

>>>> It is also about one stop under exposed.
>>> Maybe because of the fast car running.
>> Not your shot then?
>
> No. I don't adapter yet and camara. Shot was
> taken by a professional photographer. See dozens of his shots
> and complains at:
>
> http://photography-on-the.net/forum/showthread.php?p=3619915
>
> After you read it later, hope you can comment on his comments.

At about 3" aperture and above time exposures on all but the very
brightest objects are compromised by atmospheric turbulence and the
point spread function remains stubbornly around 1" arc fwhm. There are
rare days of exceptional seeing. You can beat this seeing problem by
clever software analysing webcam image streams for the instants of high
contrast lucky seeing and then shifting stacking them. This is now
widely done by amateur planetary imagers with stunning results.

>>> quality?? I keep visualizing what 6MP and 10MP
>>> images would look in my MTO and Rubinar
>>> and their differences. Any projections?
>> No. I doubt you will see much difference beyond 6Mpixel with this class
>> of lens as the effective resolution is usually limited to back of the
>> envelope ~30-40 lpm in practice. It is more than adequately sampled by
>> the 6Mpixel sensor. But the newer model of camera may still have other
>> advantages.
>
> In the following site about Diffraction Limited Photography:
>
> http://www.cambridgeincolour.com/tutorials/diffraction-photography.htm
>
> It is said that the sharpest shots are taken when the airy disc is
> inside one pixel.. so they won't overlap. What do you think would

It would look very sharp but you would have aliasing problems with that
configuration. A minimum would be 1.5x oversampled for monochrome or
better 2x oversampled for a Bayer array colour sensor.

It is not for nothing that games rendering engines spend so much of
their time anti-aliassing the generated scenes.

> be the difference if I use a 13 micron (say I can find them) pixels
> to match the airy disc linear diameter of 13.42 micron (produced
> by the F/10 of both Rubinar and MTO) versus using say a 5.7 micron
> pixels or even the theoeretical nyquist compliant 2.8 micron with
> 5 pixels per airy disc. You can notice the unsharpness in the picture
> because there are 5 pixels per airy disc (you can even notice them
> at 2-3 pixels). Now if you downsize the picture to make it match one
> pixel to one airy disc. Would the downsizing produces blending and
> other interpolation problem that it would be worse than that taken
> with the 13 micron pixel with slight aliasing? I can't simulate the
> effect hence can't decide how each of them would behave and
> how they compare.

Downsizing to first order if you bin 3x3 or 2x2 blocks of pixels
together produces the same answer as a camera with 3x or 2x bigger
pixels. Binning pixels is sometimes used in astrocameras to help with
signal to noise - and a lot of faint fuzzies are pretty small.

You really need to decide what you want to photograph and then choose
the camera. If you want maximum possible field of view and maximum
sensitivity then choose a sensor with pixel size ~diameter of point
spread function. You will get some aliasing. If you want maximum detail
then you want to oversample by 1.5-2x compared to the theoretical
Nyquist criterion. If you want to do planetary imaging then a webcam is
a heck of a lot cheaper and will work better.
>
> In the pure concept of aliasing which can exist if nyquest sampling
> (sampling at twice the maximum signal) is not used , how can you
> the aliasing? For example, a 13 micron pixel is used to correspond
> to 13.42 micron airy disc size (or other combination like 5 micron
> pixel and airy disc for faster focal ratio lens). At 100% zoom, can
> you see the aliasing?? Also I guess the aliasing is purely stair-case
> pixelization and not the aliasing in the brick case like in:
>
> http://en.wikipedia.org/wiki/Aliasing

If there are spatial frequencies present in the image beyond what the
sensor can handle then they alias.
>
> ?? I was researching this last night until I got eye strain looking at
> all the websites. Can moire pattern in the entire image indeed be
> produced by inadequate sampling or is it only stair-step pixelization?

If you have someone wearing a check or herringbone jacket or shirt then
yes. You sometimes see it happen when newsmen have unfortunate choices
of shirt on.

> Now speaking of inadequate sampling, know what. With the
> 7.4 micron Canon 300D and Airy disc size of 13.42. The Canon
> pixel is not twice smaller than the airy disc size.. so sampling
> is just 1.7X and not 2X nyquist samping minimum to avoid
> Moire pattern.
>
> The above discussion assume the MTO/Rubinar has ideal
> airy disc size and spherical aberration well controlled by
> central obstruction. This assumption is so because
> I also own another 4" scope, a 1/16th wave TMB-Triplet
> APO, so I can't just get a digicam with say 7.4 micron
> pixels because it would produce poor sampling in the
> TMB which needs 2.2 micron pixel to satisfy nyquist
> criterion. Hence you can't say that since Rubinar/MTO
> has very big airy disc, even if one pixel is used to match
> its calculated value, the actual airy disc would be twice
> bigger. Let's just assume it's same calculated size as
> 13.42 micron for sake of theoretical discussion. So
> would an airy disc with 5 pixels inside it downsampled
> to an airy disc with one pixel produce interpolation
> artifact worse than the aliasing produced by pure
> one airy disc, one pixel sampling?? Hope you can
> elaborate on this as it can make me decide what
> digicam to get.

We are going back over the same ground again and again. You don't seem
to be gaining any understanding of the issues at all. You have got
yourself confused and have stopped listening to sensible advice.

Any of the astrophotography FAQs will cover the tradeoffs inherent in
choosing a camera. I would not choose my main digicam on the basis of
astronomical use. I have a dedicated cooled CCD kit for that.

I have a feeling that whatever you buy you will be disappointed. There
is a steep learning curve in getting the best images out of telescopes
and long focal length lenses. On the plus side with digital you can
afford to experiment without running up large processing bills.

Regards,
Martin Brown

== 2 of 6 ==
Date: Thurs, May 7 2009 5:35 am
From: Hughes

On May 7, 7:10 pm, Martin Brown <|||newspam...@nezumi.demon.co.uk>
> > Do you use Aperture Priority mode or Manual? What's the
> > shutter speed you usually use (for instance in the shot you
> > shared below)?
>
> EXIF says it was 1/750s at 400ASA equivalent. Lens claims to be 0mm f0.
> Everything was manual and on a very chunky tripod. The exposure was
> deliberately short to avoid wind vibration. I have put a slice of the
> original image up at full sampled resolution - it is visibly soft.
>
> http://www.nezumi.demon.co.uk/temp/slice.jpg

Didn't you shoot it at RAW too? In the following site

http://www.cambridgeincolour.com/tutorials/RAW-file-format.htm

you can see that jpeg files can see less of the
bar lines in the resolution chart in comparison to
RAW. So some softening of your picture is caused
by jpeg compression itself.

>
> By eye I'd say roughly 2x oversampled looking at the edge transitions.

How can it be oversampled.
Based on your camera setup:

Pentax K100D 6MP
sensor size: 23.5 x 15.7 mm
Megapixels: 3,008 x 2,000
pixel pitch: 7.8 micron
Pixel scale = 206265 x 0.0078/1000= 1.6 arcsec/pixel
Dawes' Limit = 116/100mm = 1.16 arcsecond
Airy disc linear size of MTO 1000 f/10: 13.42 micron

Your pixel scale of 1.6 arcsec/pixel is bigger
than Dawes' Limit, unless you meant to say
that because of central obstruction and some
spherical aberrations, the diffraction rings of
the airy disc is brightened and the airy disc
has actual size twice larger? How can you
tell if it's 2X oversample from the picture alone??

>
>
>
> >> One snag of the MTO is that you need full aperture filters which makes
> >> it expensive to get a Wratten 87A or equivalent.
>
> > Is Wratten 87A supposed to block the heat wave in the infrared?
> > It can see thru the haze?
>
> Wratten 87A is a near infrared filter. It blocks all visible light.
> Longer wavelengths scatter less than short wavelengths and so the longer
> the wavelength you can use the better for hazy days.

Gee, it it blocks all visible light. What's the use of
using it in photography when all visible would be
block.

>
> >>>> It is also about one stop under exposed.
> >>> Maybe because of the fast car running.
> >> Not your shot then?
>
> > No. I don't adapter yet and camara. Shot was
> > taken by a professional photographer. See dozens of his shots
> > and complains at:
>
> >http://photography-on-the.net/forum/showthread.php?p=3619915
>
> > After you read it later, hope you can comment on his comments.
>
> At about 3" aperture and above time exposures on all but the very
> brightest objects are compromised by atmospheric turbulence and the
> point spread function remains stubbornly around 1" arc fwhm. There are
> rare days of exceptional seeing. You can beat this seeing problem by
> clever software analysing webcam image streams for the instants of high
> contrast lucky seeing and then shifting stacking them. This is now
> widely done by amateur planetary imagers with stunning results.

I was asking terrestrial photography and you are replying
about how aperture beyond 3" has difficulty with
atmospheric seeing.. unless.. you meant to say this
also applies at daytime terrestrially? Stacking images
taken of mountains also work?

>
> >>> quality?? I keep visualizing what 6MP and 10MP
> >>> images would look in my MTO and Rubinar
> >>> and their differences. Any projections?
> >> No. I doubt you will see much difference beyond 6Mpixel with this class
> >> of lens as the effective resolution is usually limited to back of the
> >> envelope ~30-40 lpm in practice. It is more than adequately sampled by
> >> the 6Mpixel sensor. But the newer model of camera may still have other
> >> advantages.
>
> > In the following site about Diffraction Limited Photography:
>
> >http://www.cambridgeincolour.com/tutorials/diffraction-photography.htm
>
> > It is said that the sharpest shots are taken when the airy disc is
> > inside one pixel.. so they won't overlap. What do you think would
>
> It would look very sharp but you would have aliasing problems with that
> configuration. A minimum would be 1.5x oversampled for monochrome or
> better 2x oversampled for a Bayer array colour sensor.

By aliasing you meant there is stair-stepping in the pixels or
would moire pattern image wide also be produced? Also
note that the concept of Nyquist sampling and aliasing works
in audio where 44Khz sampling is used for 22Khz signals.
But how does it translate to pixels and pictures. Even the
author of this website asked:

http://www.stanmooreastro.com/pixel_size.htm

"There is a long-standing controversy in amateur circles
as to the minimum sample that preserves resolution.
The Nyquist criterion of 2 is often cited and applied
as critical sample = 2*FWHM. But that Nyquist criterion
is specific to the minimum sample necessary to capture
and reconstruct an audio sine wave. It is not obvious
how this criterion can be applied to a 2 dimensional
near-Gaussian PSF and I have not seen any satisfactory
treatment of such."
---

This is also why I wrote this thread and inquiring, because
I can't seem to lock on this whole nyquist criterion thing
as it applies on pictures. Even the author above is
confused, maybe you can address it?

>
> It is not for nothing that games rendering engines spend so much of
> their time anti-aliassing the generated scenes.
>
> > be the difference if I use a 13 micron (say I can find them) pixels
> > to match the airy disc linear diameter of 13.42 micron (produced
> > by the F/10 of both Rubinar and MTO) versus using say a 5.7 micron
> > pixels or even the theoeretical nyquist compliant 2.8 micron with
> > 5 pixels per airy disc. You can notice the unsharpness in the picture
> > because there are 5 pixels per airy disc (you can even notice them
> > at 2-3 pixels). Now if you downsize the picture to make it match one
> > pixel to one airy disc. Would the downsizing produces blending and
> > other interpolation problem that it would be worse than that taken
> > with the 13 micron pixel with slight aliasing? I can't simulate the
> > effect hence can't decide how each of them would behave and
> > how they compare.
>
> Downsizing to first order if you bin 3x3 or 2x2 blocks of pixels
> together produces the same answer as a camera with 3x or 2x bigger
> pixels. Binning pixels is sometimes used in astrocameras to help with
> signal to noise - and a lot of faint fuzzies are pretty small.

But downsizing bigger megapixels to smaller ones can produce
blending if proportionality is not observed.

>
> You really need to decide what you want to photograph and then choose
> the camera. If you want maximum possible field of view and maximum
> sensitivity then choose a sensor with pixel size ~diameter of point
> spread function. You will get some aliasing.

By "diameter of point spread function", you meant the FWHM
(http://en.wikipedia.org/wiki/FWHM), but note that if there
is central obstruction and significant spherical aberrations,
the diffraction rings are bigger and wider, therefore won't
it be better to map the pixel to the outer diffraction edge of
the airy disc rather than its inner FWHM if one wants to get
as you mentioned maximum possible field of view and maximum
sensitivity"??

>If you want maximum detail
> then you want to oversample by 1.5-2x compared to the theoretical
> Nyquist criterion. If you want to do planetary imaging then a webcam is
> a heck of a lot cheaper and will work better.

So you have same sampling criteria as the author of the above
site when he said to sample at 3.33 the FWHM. Notice
how close is the angular diameter of the FWHM and
the Dawes' Limit resolving power, I was solving for it
and noticed it. So instead of 2X sampling of FWHM, one
must do 3.33 sampling of the FWHM ignoring atmospheric
seeing or treating the FWHM of seeing itself which amounts
to 3 arcsec.

Btw.. All Canon APS-C DSLR has same average sensor
size of 22.5 x 15mm. Hence you will get the same field of
view in all of them, what matters is only the resolution or
megapixels if you map one pixel to the point spread
function or the FWHM.
.
>
> We are going back over the same ground again and again. You don't seem
> to be gaining any understanding of the issues at all. You have got
> yourself confused and have stopped listening to sensible advice.

I'm gaining understanding of it all already. In fact, guess what,
I bought the Rubinar and MTO just to understand optics and
nothing more.

>
> Any of the astrophotography FAQs will cover the tradeoffs inherent in
> choosing a camera. I would not choose my main digicam on the basis of
> astronomical use. I have a dedicated cooled CCD kit for that.
>
> I have a feeling that whatever you buy you will be disappointed. There
> is a steep learning curve in getting the best images out of telescopes
> and long focal length lenses. On the plus side with digital you can
> afford to experiment without running up large processing bills.
>

No. I won't buy anything anymore. I'd just go to my friend house
who own a Canon 350D when I received my M42-EOS adapter
to take picture of the resolution chart and trees and do
optical analysis. That's all. Then after that. I'd sell the Rubinar
and MTO and leaving behind the world of telescopes and
telephotos with crucial wisdom gained.

Many thanks.

Hughes

> Regards,
> Martin Brown- Hide quoted text -
>
> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -

== 3 of 6 ==
Date: Thurs, May 7 2009 6:28 am
From: Chris Malcolm

In rec.photo.digital Hughes <eugenhughes@gmail.com> wrote:
> On May 6, 8:39?am, Chris Malcolm <c...@holyrood.ed.ac.uk> wrote:
>> In rec.photo.digital Hughes <eugenhug...@gmail.com> wrote:
>> > On May 6, 12:03?am, Chris Malcolm <c...@holyrood.ed.ac.uk> wrote:

>> >> Note that the front aperture of a catadioptric is not necessarily the
>> >> effective diameter of the collector lens (primary mirror), even if
>> >> it's made of glass. That mirror sits at the back of the lens body, and
>> >> the aperture at the front is in effect the end of a lens hood which
>> >> supports the secondary mirror out in front of it. The end of a lens
>> >> hood must be wider than the collector lens it's shading, or else it is
>> >> in effect a fixed aperture stop down which must be taken into account.
>>
>> >> I've already explained in considerable detail the different way in
>> >> which the aperture of the Sony catadioptric lens is specified, and
>> >> why.

>> > There is a way to settle it by empirical calculations.
>> > You wrote this a few messages back when you
>> > mention the entry pupil to be 71mm:
>> > "It's a catadioptric lens with a hole in the middle, so
>> > although its light gathering aperture is equivalent
>> > to a standard f8 lens, the apparent width of the
>> > exterior glass looks to be about 80mm, but
>> > someone who has measured the entry pupil
>> > reports it as 71mm. The diameter of the
>> > secondary mirror is 32.5mm."
>> > -----
>> > Ok. Now look at the following site with the ray trace
>> > of the light beam entering the Sony 500 reflex lens
>> > and what happens inside:
>> >http://newcamerareview.com/sony_500mm_f_8_reflex_lens_reviewid208.html
>> > You will see the 71mm parallel rays entering the
>> > objective converging as it reaches the primary mirror.
>> > Hence the 71mm can become 62.5mm as it strikes
>> > the primary mirror, hence supporting the formula
>> > Aperture = Focal length / focal ratio
>> > ? ? ? ? ? ? ? ?= 500mm/8
>> > ? ? ? ? ? ? ? ?= 62.5mm
>>
>> Interesting diagram! I hadn't seen that before. I thought it was just
>> flat glass in front of the mirror, but it seems it is a lens. Which
>> means that the collector isn't the primary mirror, but that lens in
>> front of it, so for your formula it's the size of that lens which
>> matters. ? ? ? ?

> When you use a ruler to measure the clear glass
> miniscus corrector or objective at the front, what do
> you actually get, 80mm or 71mm?

I'm beginning to wonder why I bother writing careful replies to you. I
have already explained that it measures 80mm, and where that other
71mm figure came from.

> If 80mm.. then
> shouldn't the entry pupil be 80mm too?

I can't understand how anyone who had actually been reading this
thread could ask that question.

> Let's assume
> it's 71mm and you said the collector is the corrector.
> then

> Focal ratio = 500mm/71= 7 or F/7

> So what you are saying basically is that it is an F/7 lens,
> but because there is central obstruction which blocks
> some light, Sony decided to make it F/8 so the
> exposure would be equivalent to a system without
> obstruction?

As usual you're making a lot of assumptions. As I have explained
several times now I'm suggesting that Sony call it an f8 because in
terms of light gathering power it's like a conventional f8 lens, and
this number is not just part of the paper specification of the lens,
but reported to the camera's electronics for use in various auto
functions related to exposure.

I notice in this long thread that you often ask questions which have
been answered in quite some detail before, sometimes more than once.
If you found something wrong with those previous explanations it would
help if you would indicate what the problems were.

--
Chris Malcolm

== 4 of 6 ==
Date: Thurs, May 7 2009 6:44 am
From: Hughes

On May 7, 9:28 pm, Chris Malcolm <c...@holyrood.ed.ac.uk> wrote:
> In rec.photo.digital Hughes <eugenhug...@gmail.com> wrote:
>
>
>
>
>
> > On May 6, 8:39?am, Chris Malcolm <c...@holyrood.ed.ac.uk> wrote:
> >> In rec.photo.digital Hughes <eugenhug...@gmail.com> wrote:
> >> > On May 6, 12:03?am, Chris Malcolm <c...@holyrood.ed.ac.uk> wrote:
> >> >> Note that the front aperture of a catadioptric is not necessarily the
> >> >> effective diameter of the collector lens (primary mirror), even if
> >> >> it's made of glass. That mirror sits at the back of the lens body, and
> >> >> the aperture at the front is in effect the end of a lens hood which
> >> >> supports the secondary mirror out in front of it. The end of a lens
> >> >> hood must be wider than the collector lens it's shading, or else it is
> >> >> in effect a fixed aperture stop down which must be taken into account.
>
> >> >> I've already explained in considerable detail the different way in
> >> >> which the aperture of the Sony catadioptric lens is specified, and
> >> >> why.
> >> > There is a way to settle it by empirical calculations.
> >> > You wrote this a few messages back when you
> >> > mention the entry pupil to be 71mm:
> >> > "It's a catadioptric lens with a hole in the middle, so
> >> > although its light gathering aperture is equivalent
> >> > to a standard f8 lens, the apparent width of the
> >> > exterior glass looks to be about 80mm, but
> >> > someone who has measured the entry pupil
> >> > reports it as 71mm. The diameter of the
> >> > secondary mirror is 32.5mm."
> >> > -----
> >> > Ok. Now look at the following site with the ray trace
> >> > of the light beam entering the Sony 500 reflex lens
> >> > and what happens inside:
> >> >http://newcamerareview.com/sony_500mm_f_8_reflex_lens_reviewid208.html
> >> > You will see the 71mm parallel rays entering the
> >> > objective converging as it reaches the primary mirror.
> >> > Hence the 71mm can become 62.5mm as it strikes
> >> > the primary mirror, hence supporting the formula
> >> > Aperture = Focal length / focal ratio
> >> > ? ? ? ? ? ? ? ?= 500mm/8
> >> > ? ? ? ? ? ? ? ?= 62.5mm
>
> >> Interesting diagram! I hadn't seen that before. I thought it was just
> >> flat glass in front of the mirror, but it seems it is a lens. Which
> >> means that the collector isn't the primary mirror, but that lens in
> >> front of it, so for your formula it's the size of that lens which
> >> matters. ? ? ? ?
> > When you use a ruler to measure the clear glass
> > miniscus corrector or objective at the front, what do
> > you actually get, 80mm or 71mm?
>
> I'm beginning to wonder why I bother writing careful replies to you. I
> have already explained that it measures 80mm, and where that other
> 71mm figure came from.
>
> > If 80mm.. then
> > shouldn't the entry pupil be 80mm too?
>
> I can't understand how anyone who had actually been reading this
> thread could ask that question.

Well. It's because if the clear aperture size is 80mm, the entry
pupil should be 80mm and not 71mm so I thought if
the 80mm is from lens cell to lens cell. If it's 80mm
clear aperture, entry pupil should be 80mm too.
>
> > Let's assume
> > it's 71mm and you said the collector is the corrector.
> > then
> > Focal ratio = 500mm/71= 7 or F/7
> > So what you are saying basically is that it is an F/7 lens,
> > but because there is central obstruction which blocks
> > some light, Sony decided to make it F/8 so the
> > exposure would be equivalent to a system without
> > obstruction?
>
> As usual you're making a lot of assumptions. As I have explained
> several times now I'm suggesting that Sony call it an f8 because in
> terms of light gathering power it's like a conventional f8 lens, and
> this number is not just part of the paper specification of the lens,
> but reported to the camera's electronics for use in various auto
> functions related to exposure.
>
> I notice in this long thread that you often ask questions which have
> been answered in quite some detail before, sometimes more than once.
> If you found something wrong with those previous explanations it would
> help if you would indicate what the problems were.

Just clarifying because I've never heard of an f/7 system
being reported as f/8 because there central obstruction,
it never happens in the world of Celestron, Meade,
Questar, Orion, etc. It's the weird thing I've heard unless
perhaps you are somewhat wrong in that analysis. But
of course you could be right but the reviewers never
mention it.

Hughes

>
> --
> Chris Malcolm- Hide quoted text -
>
> - Show quoted text -

== 5 of 6 ==
Date: Thurs, May 7 2009 6:56 am
From: Chris Malcolm

In rec.photo.digital Hughes <eugenehughesx@yahoo.com> wrote:
> On May 7, 7:10?pm, Martin Brown <|||newspam...@nezumi.demon.co.uk>
>> > Do you use Aperture Priority mode or Manual? What's the
>> > shutter speed you usually use (for instance in the shot you
>> > shared below)?
>>
>> EXIF says it was 1/750s at 400ASA equivalent. Lens claims to be 0mm f0.
>> Everything was manual and on a very chunky tripod. The exposure was
>> deliberately short to avoid wind vibration. I have put a slice of the
>> original image up at full sampled resolution - it is visibly soft.
>>
>> http://www.nezumi.demon.co.uk/temp/slice.jpg

> Didn't you shoot it at RAW too? In the following site

> http://www.cambridgeincolour.com/tutorials/RAW-file-format.htm

> you can see that jpeg files can see less of the
> bar lines in the resolution chart in comparison to
> RAW. So some softening of your picture is caused
> by jpeg compression itself.

You can't compare a RAW image with a JPEG image because a RAW image is
not in a suitable form for viewing. What people mean by comparing a
RAW image to a JPEG is comparing an ex-camera JPEG with a less
compressed JPEG produced by a more powerful and sophisticated
ex-camera RAW conversion program. How much difference in detail
resolution there is depends on the quality of the in-camera
conversion. Some cameras do good enough conversions that no difference
is visible. In others the difference is quite marked.

>> >> One snag of the MTO is that you need full aperture filters which makes
>> >> it expensive to get a Wratten 87A or equivalent.
>>
>> > Is Wratten 87A supposed to block the heat wave in the infrared?
>> > It can see thru the haze?
>>
>> Wratten 87A is a near infrared filter. It blocks all visible light.
>> Longer wavelengths scatter less than short wavelengths and so the longer
>> the wavelength you can use the better for hazy days.

> Gee, it it blocks all visible light. What's the use of
> using it in photography when all visible would be
> block.

Because you're not putting it over your spectacles, you're putting it
in front of a camera sensor which responds to a wider range of
frequencies. Have you never heard of infrared photography?

>> At about 3" aperture and above time exposures on all but the very
>> brightest objects are compromised by atmospheric turbulence and the
>> point spread function remains stubbornly around 1" arc fwhm. There are
>> rare days of exceptional seeing. You can beat this seeing problem by
>> clever software analysing webcam image streams for the instants of high
>> contrast lucky seeing and then shifting stacking them. This is now
>> widely done by amateur planetary imagers with stunning results.

> I was asking terrestrial photography and you are replying
> about how aperture beyond 3" has difficulty with
> atmospheric seeing.. unless.. you meant to say this
> also applies at daytime terrestrially?

Have you already forgotten that I explained that with a 500mm lens I
have this kind of problem quite seriously with terrestial images past
a mile or so in distance?

--
Chris Malcolm

== 6 of 6 ==
Date: Thurs, May 7 2009 7:13 am
From: Hughes

On May 7, 9:56 pm, Chris Malcolm <c...@holyrood.ed.ac.uk> wrote:
> In rec.photo.digital Hughes <eugenehugh...@yahoo.com> wrote:
>
>
>
>
>
> > On May 7, 7:10?pm, Martin Brown <|||newspam...@nezumi.demon.co.uk>
> >> > Do you use Aperture Priority mode or Manual? What's the
> >> > shutter speed you usually use (for instance in the shot you
> >> > shared below)?
>
> >> EXIF says it was 1/750s at 400ASA equivalent. Lens claims to be 0mm f0.
> >> Everything was manual and on a very chunky tripod. The exposure was
> >> deliberately short to avoid wind vibration. I have put a slice of the
> >> original image up at full sampled resolution - it is visibly soft.
>
> >>http://www.nezumi.demon.co.uk/temp/slice.jpg
> > Didn't you shoot it at RAW too? In the following site
> >http://www.cambridgeincolour.com/tutorials/RAW-file-format.htm
> > you can see that jpeg files can see less of the
> > bar lines in the resolution chart in comparison to
> > RAW. So some softening of your picture is caused
> > by jpeg compression itself.
>
> You can't compare a RAW image with a JPEG image because a RAW image is
> not in a suitable form for viewing. What people mean by comparing a
> RAW image to a JPEG is comparing an ex-camera JPEG with a less
> compressed JPEG produced by a more powerful and sophisticated
> ex-camera RAW conversion program. How much difference in detail
> resolution there is depends on the quality of the in-camera
> conversion. Some cameras do good enough conversions that no difference
> is visible. In others the difference is quite marked.

Well. They can be compared. Here's how. When you view a RAW.
Debayerazation or interpolation of colors is done so you can
view it, you can then save it at TIFF. Anytime you do JPEG.
The compression can kill the details by producing 8x8 grid
pattern that removes many details. Now comparing TIFF to
JPEG, the TIFF would show more details in the resolution
chart.

>
> >> >> One snag of the MTO is that you need full aperture filters which makes
> >> >> it expensive to get a Wratten 87A or equivalent.
>
> >> > Is Wratten 87A supposed to block the heat wave in the infrared?
> >> > It can see thru the haze?
>
> >> Wratten 87A is a near infrared filter. It blocks all visible light.
> >> Longer wavelengths scatter less than short wavelengths and so the longer
> >> the wavelength you can use the better for hazy days.
> > Gee, it it blocks all visible light. What's the use of
> > using it in photography when all visible would be
> > block.
>
> Because you're not putting it over your spectacles, you're putting it
> in front of a camera sensor which responds to a wider range of
> frequencies. Have you never heard of infrared photography?

I have heard of IR photography because I have some IR
filters left in the days of Sony 717. But when you do
IR photography, you can't view the visible if you use
strong IR filter. What Martin seems to be saying is that
to remove the haze in the atmosphere and see things
clearly, put IR filter to filter out the visible. Then what's
the use of seeing things just IR and no visible. I thought
he was saying that there is a filter to cut haze and see
visible better.

>
> >> At about 3" aperture and above time exposures on all but the very
> >> brightest objects are compromised by atmospheric turbulence and the
> >> point spread function remains stubbornly around 1" arc fwhm. There are
> >> rare days of exceptional seeing. You can beat this seeing problem by
> >> clever software analysing webcam image streams for the instants of high
> >> contrast lucky seeing and then shifting stacking them. This is now
> >> widely done by amateur planetary imagers with stunning results.
> > I was asking terrestrial photography and you are replying
> > about how aperture beyond 3" has difficulty with
> > atmospheric seeing.. unless.. you meant to say this
> > also applies at daytime terrestrially?
>
> Have you already forgotten that I explained that with a 500mm lens I
> have this kind of problem quite seriously with terrestial images past
> a mile or so in distance?

Well. I was asking terrestrially and he was answering astronomically.
Anyway, here's a question that is not yet answered (even by you)
and that's why I keep writing.

http://www.cambridgeincolour.com/tutorials/diffraction-photography.htm

In the above site, It seems to be suggested that in
terrestrial photography, airy disc size must be smaller than
pixel size for diffraction limited photography, I was confirming
if it is true with Mr. Brown, and he replied in terms of
astronomical where there seems to be other laws.

It's like this. In normal photography with Canon EOS
with stock lens. The airy disc is always smaller than
the pixel. This is because the normal Canon EOS
DSLR has say 15 arcsecond per pixel coverage
for the say 300D. Now why can't we make the rule
that airy disc size must not be larger than pixel as
emphasized in the above site. Mr. Peterson and
others seem not to agree with terrestrial photography
experts.

Anyway, I wonder if aliasing can be seen in
normal terrestrial photography using 6-15
Megapixels. If they can't be seen. Then what's
the problem of mapping airy disc size to pixel
size in the Rubinar when the airy disc size is even
much smaller in normal stock lens photography.
???

Hope you get my point and Mr. Brown can address
this and not frame it astronomically but terrestrially.

When answered, then I got what I seek and I'm outta
here.

Hughes

>
> --
> Chris Malcolm- Hide quoted text -
>
> - Show quoted text -

==============================================================================
TOPIC: Fuji E550: camera settings & config lost when changing batteries
http://groups.google.com/group/rec.photo.digital/t/e44c3acae01af381?hl=en
==============================================================================

== 1 of 1 ==
Date: Thurs, May 7 2009 4:36 am
From: "Al, Cambridge, UK"

On May 7, 1:33 am, "JohnV@nn" <jmvan...@gmail.com> wrote:
> Apparently there's a (button-cell?) battery in there that backs up the
> camera config when you have the batteries out, but that appears to
> have gone dead in my E550. Everything is reset to factory defaults
> when I change the main batteries. Oddly, the manual makes no mention
> of any backup battery for the settings. Is there a button cell
> battery in there somewhere that is replaceable?

I have the E900, which I believe is similar.
I normally swap the batteries for a spare set when charging, but on
one occasion when I removed the batteries for charging overnight I
found that the camera had reset itself - the camera appears to have a
capacitor to maintain settings while batteries are removed, but that
only holds up for a few hours.

However if you find that settings are lost as soon as you remove the
batteries, that's probably a fault.

Brilliant cameras though, wish they still did something similar.
Al

==============================================================================
TOPIC: Jpeg file size and picture quality
http://groups.google.com/group/rec.photo.digital/t/5213471eccf5c624?hl=en
==============================================================================

== 1 of 2 ==
Date: Thurs, May 7 2009 5:17 am
From: curious guy

I wanted to email someone a picture that was 467,007 bytes. (The
picture was from a newsgroup. I did not take it.) I thought that was
too big so I experimented with resizing it with PhotoImpact 4.2. I
discovered that if I just loaded it and re-saved it without reducing
its dimensions, it went from 467,007 bytes to 37,341 bytes. I have
PhotoImpact set to use "Best" generation quality.

When I look at the pictures, I can not see any difference until I zoom
way in. Why is there such a huge difference in file sizes
(12.50654776 times)?

If there is another newsgroup where this question would be more
appropriate, please let me know.

== 2 of 2 ==
Date: Thurs, May 7 2009 5:42 am
From: Martin Brown <|||newspam|||@nezumi.demon.co.uk>

curious guy wrote:
> I wanted to email someone a picture that was 467,007 bytes. (The
> picture was from a newsgroup. I did not take it.) I thought that was
> too big so I experimented with resizing it with PhotoImpact 4.2. I
> discovered that if I just loaded it and re-saved it without reducing
> its dimensions, it went from 467,007 bytes to 37,341 bytes. I have
> PhotoImpact set to use "Best" generation quality.

It is a reasonable question although you might want to look in the
archives it has been done to death several times before.

The short answer is that a JPEG encoded image uses lossy compression
designed so as not to be obvious to the human viewer on photographic
source material. And it is very good at what it does. PhotoImpacts
"Best" setting doesn't sound very good if the original image was also a
JPEG file but would be reasonable if it were a BMP.

There is a certain amount of grade inflation in the names given to JPEG
encoding settings. No software labels them "rubbish", "poor" or "barely
adequate" - the marketting men prefer "normal", "good", "very good" or
numbers.

And a few cameras like Nikon and Canon in their maximum quality setting
save with a quantisation matrix that wastes space without storing much
more information. You can generally get these files smaller without any
perceptible visual change in a first generation JPEG.
>
> When I look at the pictures, I can not see any difference until I zoom
> way in. Why is there such a huge difference in file sizes
> (12.50654776 times)?
>
> If there is another newsgroup where this question would be more
> appropriate, please let me know.

If you put the two files up somewhere it would be easy enough to see
what the actual quantisation matrices used by PhotoImpact and the
original source file are. The IJG scale of 0..100 is commonly used

Regards,
Martin Brown

==============================================================================
TOPIC: Photographic rights
http://groups.google.com/group/rec.photo.digital/t/95ce520de64e5844?hl=en
==============================================================================

== 1 of 1 ==
Date: Thurs, May 7 2009 5:24 am
From: "whisky-dave"

"Eric Miller" <miller_nospam_eric@bellsouth.net> wrote in message
news:tnkMl.38219$qa.19687@bignews4.bellsouth.net...
>
> "whisky-dave" <whisky-dave@final.front.ear> wrote in message
> news:gtsa2d$ona$1@qmul...
>>
>> "Don Stauffer" <stauffer@usfamily.net> wrote in message
>> news:4a01a36e$0$48219$815e3792@news.qwest.net...
>>
>>>
>>> We have to let lawyers and judges make a living, right?
>>>
>>> Seriously, laws cannot be written to cover EVERY situation. That is
>>> what courts are for. In the above situation, I can see such a case going
>>> to court and letting the judge or jury decide. The best way to avoid
>>> court is to get any agreement in writing. The answer lies with the best
>>> lawywer :-)
>>
>> It's a sad situation though isn;t it, in that being in the right or the
>> wrong
>> depends on how good your lawyer is, which is probably linked to how much
>> he charges.
>> It seems that basically a laywer is employed to lie on your behalf, the
>> more you can afford
>> the better the lie he'll construct.
>>
>>
>
> That's a fairly simplistic description of something that is almost never
> so simply stated. Given the limited facts supplied by the OP it is fairly
> easy to see how there may be a misunderstanding concerning the things that
> were not contemplated by the photographer or the model at the time of the
> gift.

But that shouldn't matter, but that's the problem with the law isn;t it.
If we';re worried by what the term gift means then you seem to be impling
that the word gift can change depending on your lawyers skill.

> If the photograph later becomes valuable (e.g., the later actress dies
> tragically and these are the only semi-nude images of her) and her heirs
> publish the image after the photographer has signed a contract to sell
> prints (because he duplicated the negative for the model to make her own
> prints but did not anticipate that she might seek to publish them). Or
> maybe the photographer becomes famous and the negative represents one of a
> few examples of his early work that the model now wants to publish for
> profit. In such situations, it is easy to see how each party might have a
> different understanding of what rights,

But those rightsd are writern in law surelty they don;t change depending on
the laywer you employ or the salery he's paid.

>if any, existed and may have been transferred when the print and negative
>were handed to the model. In fact, if nothing specific was stated at the
>time of the gift, they might each legitimately view each others intent very
>differently.

But the law should be the law.

>
> In neither case would the lawyer be paid to lie: only to advocate his
> client's version of the facts that would underlie any future verdict.

Did he jump or was he pushed shouldn't be decided on the size of the laywers
pay packet.

==============================================================================
TOPIC: Tripod recommendations
http://groups.google.com/group/rec.photo.digital/t/e59e681e1ff2393a?hl=en
==============================================================================

== 1 of 5 ==
Date: Thurs, May 7 2009 5:56 am
From: "whisky-dave"

A friend has asked me if I know anything about tripods, so I said they have
3 legs
and the heavy and more difficult to move they are the better they'll keep
the camera steady.

So I wasn;t much help :-)

This tripod will mostly be used with a meduim format film camera probably
for
long expossures in the region of seconds for some college project.

It will need to be resonably portable for her to carry and she'll be using
public
transport mostly. Price range, well got to be under £100 probably nearer
£50.
I suggested she hired one when needed, but she didn;t seem interested.

Anyone have any thoughts or links that might be useful to her.
cheers

== 2 of 5 ==
Date: Thurs, May 7 2009 6:15 am
From: floyd@apaflo.com (Floyd L. Davidson)

"whisky-dave" <whisky-dave@final.front.ear> wrote:
> A friend has asked me if I know anything about tripods, so I said they have
>3 legs
>and the heavy and more difficult to move they are the better they'll keep
>the camera steady.
>
>So I wasn;t much help :-)
>
>This tripod will mostly be used with a meduim format film camera probably
>for
>long expossures in the region of seconds for some college project.
>
>It will need to be resonably portable for her to carry and she'll be using
>public
>transport mostly. Price range, well got to be under £100 probably nearer
>£50.
>I suggested she hired one when needed, but she didn;t seem interested.
>
>Anyone have any thoughts or links that might be useful to her.
>cheers

A tripod that costs £50 is quite useful. For holding
lights, backgrounds, or whatever. Don't put your camera
on one though...

--
Floyd L. Davidson <http://www.apaflo.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@apaflo.com

== 3 of 5 ==
Date: Thurs, May 7 2009 6:38 am
From: SMS

whisky-dave wrote:

> Anyone have any thoughts or links that might be useful to her.
> cheers

I'd look for a used Manfrotto 3001 or 3021 on craigslist.org (easy to
find on the craigslist in my area as people go to lighter weigh tripods).

== 4 of 5 ==
Date: Thurs, May 7 2009 6:41 am
From: Grimly Curmudgeon

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "whisky-dave"
<whisky-dave@final.front.ear> saying something like:

>
>It will need to be resonably portable for her to carry and she'll be using
>public
>transport mostly. Price range, well got to be under £100 probably nearer
>£50.
>I suggested she hired one when needed, but she didn;t seem interested.
>
>Anyone have any thoughts or links that might be useful to her.

Cheapy tripods from www.7dayshop.com aren't bad for the money,
especially if it's for short term use and she'd not be bothered if it
got stolen or damaged.

== 5 of 5 ==
Date: Thurs, May 7 2009 6:41 am
From: Grimly Curmudgeon

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember floyd@apaflo.com (Floyd L.
Davidson) saying something like:

>A tripod that costs £50 is quite useful. For holding
>lights, backgrounds, or whatever. Don't put your camera
>on one though...

Shite.

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