Photoshop How To Use: rec.photo.digital - 25 new messages in 8 topics

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TOPIC: Haifa, Kishon - new slide video!
http://groups.google.com/group/rec.photo.digital/t/fd46785c98494d62?hl=en
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== 1 of 1 ==
Date: Wed, Apr 22 2009 10:42 pm
From: Alexander Blokhin

http://localcraft.blogspot.com/

Please see!

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TOPIC: DLSR and Pixels
http://groups.google.com/group/rec.photo.digital/t/4e110bd229839ce7?hl=en
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== 1 of 3 ==
Date: Thurs, Apr 23 2009 12:15 am
From: Eugene

On Apr 23, 10:30 am, Derge <bde...@gmail.com> wrote:
> On Apr 22, 8:18 pm, Eugene <eugenhug...@gmail.com> wrote:
>
> > DLSR is supposed to be good because the pixel
> > is bigger. In the Canon 300D. The pixel size is
> > 7.4 micron, 6+ megapixels. Now with the Canon 1000D,
> > pixel size is 5.7 micron, 10+megapixel. Both has
> > the same CCD size of 22.5 x 15mm. Notice the pixel
> > size has gone smaller. Wouldn't this defeat the purpose
> > of DSLR (Bigger Pixel Rocks)? Has anyone compared
> > the quality of the 300D vs 1000D? Which is cleaner?
> > Using the same 22.5 x 15mm grid, how small can
> > the pixel get (or how large can the megapixels be,
> > as they are inversely proportional) before noise would become bad
> > enough that it won't be far from
> > point&shoot CCDs?
>
> > E
>
> Well, yes and no. The point of DSLRs isn't that they have big pixels.
> The point is that they have big sensors.
>

What? But pixels are sensors. What you talking about?

> The notion of "pixel level" noise is a bit of a red herring, since
> ultimately we, as human beings, need to view an image taken with any
> camera at fixed dimensions, whether in print or on the web. The camera
> usually doesn't determine what those dimensions are: We do! If you're
> sending snapshots to your grandmother, for instance, they're only
> going to be 800x600 JPEGs, no matter what camera took them. A
> comparison at that size would give you similar pictures. If anything,
> the images from the EOS 1000D would be *less* noisy *because* it has
> smaller pixels, which means lower read noise per unit area.

Or you mean bigger pixels? How can smaller pixels be less noisy?

>
> You obviously understand the relationship between pixel size and
> noise. The other edge of the sword is this: Anything "lost" by using
> smaller pixels can be reclaimed by resizing the larger image in
> Photoshop. This only works in one direction, obviously. Smaller pixels
> give us a choice.

== 2 of 3 ==
Date: Thurs, Apr 23 2009 12:46 am
From: "David J Taylor"

Eugene wrote:
[]
> Or you mean bigger pixels? How can smaller pixels be less noisy?
>
> E

If you are viewing the complete image, is it better that it be made up of
5MP or 10MP, given that each of the 10MP pixels will be smaller, slightly
noisier, but that the 10MP image will be a little sharper?

Perhaps the optimum varies for different images, and some shots will
benefit more from the greater sharpness, and others from the lower noise?

Also, bear in mind that a more recent camera may have slight improvements,
resutling in a better signal-to-noise ratio for each pixel.

There isn't a single answer, you see.

David

== 3 of 3 ==
Date: Thurs, Apr 23 2009 1:58 am
From: Doug Jewell

Eugene wrote:
>
> DLSR is supposed to be good because the pixel
> is bigger. In the Canon 300D. The pixel size is
> 7.4 micron, 6+ megapixels. Now with the Canon 1000D,
> pixel size is 5.7 micron, 10+megapixel. Both has
> the same CCD size of 22.5 x 15mm. Notice the pixel
> size has gone smaller. Wouldn't this defeat the purpose
> of DSLR (Bigger Pixel Rocks)? Has anyone compared
> the quality of the 300D vs 1000D? Which is cleaner?
All else being equal, bigger pixel size would be lower
noise. But like many things, all else isn't equal. Modern
cameras have improved sensor design, including less sensor
area dedicated to support electronics, so the actual
sensitive area hasn't shrunk by the same proportion that the
MP increase would indicate. Additionally support circuitry
has improved, post-processing (both in and out of camera)
has improved, so once again the performance doesn't scale
linearly with MP. While I haven't done a direct comparison,
and I have a 450D not a 1000D, the "vibe" I get from my 12MP
450D is that it is only slightly noisier than the older
lower MP cameras. In some cases maybe less noisy. The
increase in noise is also offset by a dramatic increase in
resolution. I'm confident that a 450D image downsampled to
6MP would be significantly better than a 300D image.
> Using the same 22.5 x 15mm grid, how small can
> the pixel get (or how large can the megapixels be,
> as they are inversely proportional) before noise would become bad
> enough that it won't be far from
> point&shoot CCDs?
Put it this way. The 12MP P&S digital cameras (eg SX200IS)
have a pixel density of 43MP/cm^2. the 22.3x14.9mm sensor
used in the cropped canon cameras has an area of 3.3227cm^2,
so for the same pixel density an SLR could have a 142MP
sensor. ie, a 142MP 1.6x crop DSLR would deliver similar
noise levels to a 12MP P&S.
The current 10-15MP cameras are obviously a long long way
short of the pixel densities in P&S cameras, and despite
concern that the higher pixel counts are increasing noise,
they are still significantly better than P&S.
>
> E

==============================================================================
TOPIC: Are todays LCD screen any good in bright weather
http://groups.google.com/group/rec.photo.digital/t/d70e4ce3863b627f?hl=en
==============================================================================

== 1 of 3 ==
Date: Thurs, Apr 23 2009 12:39 am
From: "David J Taylor"

Charles wrote:
[]
> LCDs are terrible in outside bright light.

You haven't seen a transreflective LCD, have you?

David

== 2 of 3 ==
Date: Thurs, Apr 23 2009 4:17 am
From: "J. Clarke"

Ken wrote:
> "Jürgen Exner" <jurgenex@hotmail.com> wrote in message
> news:nakuu4h146rklkd5eu4odv82aorsc8v3kh@4ax.com...
>> "Ken" <none@none.co.uk> wrote:
>>> I have an older Nikon 7900 with 2" screen and even in normal light
>>> sometimes
>>> have to take a guess when outside that I have got the subject in
>>> frame. I was thinking of getting a modern digi camera with 2.5 or
>>> bigger LCD screen but only if I feel convinced they are better to
>>> use outside. Whats the point
>>> in having to guess the shot???
>>
>> That's what a viewfinder is for. They are becoming a rare breed, but
>> you can still find them.
>>
>> jue
>
> Sone of the Canons have them but not a wide angle lens I need. My
> Nikon 7900 has a viewfinder but with only a 75% of what you see is
> what you get. So I end up using it and cropping in the software to
> get what I need for my idea of the right composition.

How wide do you need to go? The 7900 has 38mm equivalent. A Canon G10 goes
to 28mm equivalent, which is a great deal wider, but still has the 77% or so
optical finder. You might want to look into something like an SX10IS, which
has an eye-level LCD that works fine in sunlight and a lens that goes to
28mm equivalent.

Alternatively, just get yourself a DSLR and whatever wide angle you need and
be done with it.

== 3 of 3 ==
Date: Thurs, Apr 23 2009 6:20 am
From: Chris Malcolm

Ken <none@none.co.uk> wrote:
> I have an older Nikon 7900 with 2" screen and even in normal light sometimes
> have to take a guess when outside that I have got the subject in frame. I
> was thinking of getting a modern digi camera with 2.5 or bigger LCD screen
> but only if I feel convinced they are better to use outside. Whats the point
> in having to guess the shot???

> Anyone with a modern camera with the LCD that will work in brighter
> conditions?

I haven't, but my camera also has a live view video output, so with a
piece of wire and a portable LCD monitor which is easily viewable in
bright sunlight (and devours batteries :-) I can use live view in the
sun.

But I mostly use it as a way of seeing the live view when I'm several
feet away from the camera. For simple holiday snaphot portability a
small folding black umbrella keeps both rain and sun off the camera.

--
Chris Malcolm

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TOPIC: Great forum!
http://groups.google.com/group/rec.photo.digital/t/ac2220a39a1c052b?hl=en
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== 1 of 2 ==
Date: Thurs, Apr 23 2009 12:49 am
From: Bob Larter

Focus wrote:
> http://atlantic-diesel.com
>
> International forum with very much possibilities.
>
> Check it out. Free and no advertisements.

Is there some particular reason you felt it necessary to spam that URL
to *11* different groups?

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------

== 2 of 2 ==
Date: Thurs, Apr 23 2009 6:26 am
From: "Atheist Chaplain"

"^Tems^" <stevebrooks13@live.com> wrote in message
news:759sb1F17bdj8U1@mid.individual.net...
> Focus wrote:
>> http://atlantic-diesel.com
>>
>> International forum with very much possibilities.
>>
>> Check it out. Free and no advertisements.
>>
>>
>
> A great forum with 7 posts with all but one of these made my Paul Bertram
>
> Yep, a great forum
>
>
>
>

well of course he wants his own forum, then he can just delete any
dissenting opinions, after all he is regularly getting his arse handed to
him in a hand basket on Usenet :-)

--
[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: Canon DSLR Live View
http://groups.google.com/group/rec.photo.digital/t/21ca0cd9457ba13c?hl=en
==============================================================================

== 1 of 6 ==
Date: Thurs, Apr 23 2009 1:31 am
From: Doug Jewell

Shawn Hirn wrote:
> In article
> <49ef8c0a$0$12595$5a62ac22@per-qv1-newsreader-01.iinet.net.au>,
> Doug Jewell <ask@and.maybe.ill.tell.you> wrote:
>
>> Yes. Slightly more useful than a gimmick, but only slightly.
>> Out of about 10,000 shots I've made with my 450D, I'd say
>> I've used liveview for no more than 20. A couple of "over
>> the crowd" shots at a local parade, and a few macro shots.
>
> To each his own. I use my 450D in liveview mode a lot. I am very happy
> with it.
The slow focussing, lag, and extra battery drain don't
exactly thrill me. If I wanted those features I use my P&S.
For what I do most (candid portraits), live-view is
completely hopeless.

== 2 of 6 ==
Date: Thurs, Apr 23 2009 1:36 am
From: Doug Jewell

Eugene wrote:
> On Apr 23, 5:28 am, Doug Jewell <a...@and.maybe.ill.tell.you> wrote:
>> Eugene wrote:
>>> Hi,
>>> Canon Live View in the 1000D/XS for example
>>> can give live view in the LCD rather than
>>> optical viewfinder. How come previous Digital
>>> SLR didn't make this feature available?
>> To provide live-view requires additional circuitry on the
>> sensor chip to do continuous live read-out. This additional
>> circuitry adds to the chip cost & complexity, and also
>> degrades still image quality slightly - the presence of the
>> live read-out circuitry means less area available for light
>> gathering.
>> Earlier DSLRs, I guess the manufacturers decided that people
>> wouldn't want live-view on a DSLR and would prefer the
>> better image quality. As chip technology has progressed,
>> they can now do live-view and maintain image quality. And
>> since there is now demand in DSLR for the feature (because
>> of the P&S brigade upgrading to DSLR), they are starting to
>> put it in most models now.
>>
>>> Also anyone owns any one of these Canon Live View DSLR?
>> Yes. Slightly more useful than a gimmick, but only slightly.
>> Out of about 10,000 shots I've made with my 450D, I'd say
>> I've used liveview for no more than 20. A couple of "over
>> the crowd" shots at a local parade, and a few macro shots.
>>
>>> I'd use a 1000mm f/10 Russian Telephoto on
>>> it. Can the contrast autofocus work? The
>>> telephoto is manual and have to turn it
>>> manually. So I guess that I can see the view
>>> direclty in the LCD to see the best focus?
>>> What then is the function of Contrast or
>>> AF autofocus in this case?
>> If your lens is only manual, then guess what? Surprise
>> surprise, autofocus won't work. No, not even contrast detect
>
> Autofocus may not work but if you turn the lens manually,
> focus confirmation can light up if the correct focus is
> achieved. So it is like Autofocus except you turn the
> lens manually.This is why some adapter for non-canon
> manual lens uses chip to activate the Canon confirm
> confirmation like:
>
> http://www.rugift.com/photocameras/canon-eos-adapter-focus-confirm.htm
On the 450D focus-confirm doesn't work in live-view mode. I
would be very surprised if it does in the 1000D since it is
a lower spec camera released at approximately the same time.
The closest thing you have to focus-confirm is your
assesment of the image you see at 10x magnification.
Focus-confirm is an indicator in the viewfinder, and as far
as I know it only works with F5.6 or faster lenses.
>
> What do you say?
>
> E
>
>
>
>> autofocus. What you can do in live-view mode is magnify the
>> image x5 or x10 (on the 450D you can, I assume the 1000
>> would be the same) so you can preview the manual focus. Will
>> probably be a bit grainy with an F10 lens though.
>>
>>
>>
>>
>>
>>> Thanks.
>>> E.- Hide quoted text -
>> - Show quoted text -
>

== 3 of 6 ==
Date: Thurs, Apr 23 2009 1:56 am
From: Robert Spanjaard

On Wed, 22 Apr 2009 18:21:41 -0400, Charles wrote:

>>> I have live view and frankly, don't know what all of the fuss is
>>> about. It has very little usefulness.
>>>
>>> So you're out with your 1000mm lens. Good. And it's on a tripod,
>>> because it is, after all, a 1000 mm lens. So what real advantage does
>>> live view have -- esp. in daylight where you can't see it as well. It
>>> really isn't too difficult to look through the viewfinder and get a
>>> much better view of the picture.
>>
>> macro is one scenario where live view is fantastic.
>
> To be sure ... it can save the day with some macro shots!

I prefer an anglefinder attached to the optical viewfinder.

What I do like about Live View (on my Powershot S80), is some extra info
like the live histogram.

--
Regards, Robert http://www.arumes.com

== 4 of 6 ==
Date: Thurs, Apr 23 2009 3:09 am
From: Bigguy

Pat wrote:
> On Apr 22, 7:04 am, Eugene <eugenhug...@gmail.com> wrote:
>> Hi,
>>
>> Canon Live View in the 1000D/XS for example
>> can give live view in the LCD rather than
>> optical viewfinder. How come previous Digital
>> SLR didn't make this feature available?
>>
>> Also anyone owns any one of these Canon Live View DSLR?
>>
>> I'd use a 1000mm f/10 Russian Telephoto on
>> it. Can the contrast autofocus work? The
>> telephoto is manual and have to turn it
>> manually. So I guess that I can see the view
>> direclty in the LCD to see the best focus?
>> What then is the function of Contrast or
>> AF autofocus in this case?
>>
>> Thanks.
>>
>> E.
>
> I have live view and frankly, don't know what all of the fuss is
> about. It has very little usefulness.
>
It's pretty much essential when doing astro' photography... true - we
did 'manage' without, before, but LV is really useful and prevents neck
and back strain too.

Guy

== 5 of 6 ==
Date: Thurs, Apr 23 2009 6:04 am
From: Chris Malcolm

Doug Jewell <ask@and.maybe.ill.tell.you> wrote:
> Shawn Hirn wrote:
>> In article
>> <49ef8c0a$0$12595$5a62ac22@per-qv1-newsreader-01.iinet.net.au>,
>> Doug Jewell <ask@and.maybe.ill.tell.you> wrote:
>>
>>> Yes. Slightly more useful than a gimmick, but only slightly.
>>> Out of about 10,000 shots I've made with my 450D, I'd say
>>> I've used liveview for no more than 20. A couple of "over
>>> the crowd" shots at a local parade, and a few macro shots.
>>
>> To each his own. I use my 450D in liveview mode a lot. I am very happy
>> with it.

> The slow focussing, lag, and extra battery drain don't
> exactly thrill me. If I wanted those features I use my P&S.
> For what I do most (candid portraits), live-view is
> completely hopeless.

The slow focussing and lag are a feature of Canon's specific current
implementation of live view. There are other way of doing it without
those problems, one of which is used in the Sony Alpha live view
models which use fast phase detection AF in live view, no difference
in speed when using live view.

--
Chris Malcolm

== 6 of 6 ==
Date: Thurs, Apr 23 2009 6:11 am
From: Chris Malcolm

Mr. Strat <rag@nospam.techline.com> wrote:
> In article
> <6c6c28aa-a852-4739-a050-2b5d2daa24c7@z16g2000prd.googlegroups.com>,
> Eugene <eugenhughes@gmail.com> wrote:

>> Canon Live View in the 1000D/XS for example
>> can give live view in the LCD rather than
>> optical viewfinder. How come previous Digital
>> SLR didn't make this feature available?

> Because it's a feature for morons. But if you like wasting your battery
> and looking at a little TV screen, be my guest. One viewfinder is
> plenty.

I'm not much interested in simple back panel live view, because if you
can see the panel you can simply move the camera closer to your eye
and see through the viewfinder. But I've unexpectedly found flippable
LCD live view so extremely useful that I will now not buy a DSLR
without it. I now routinely take many photographs from camera
positions where it would either be rather difficult or impossible to
get my eye behind the viewfinder.

--
Chris Malcolm

==============================================================================
TOPIC: Matching Pixel Size and Telephoto
http://groups.google.com/group/rec.photo.digital/t/75c4b5506848d404?hl=en
==============================================================================

== 1 of 7 ==
Date: Thurs, Apr 23 2009 2:09 am
From: Hughes

Hi,

My experience is mostly on astronomical telescopes
and I now want to view terrestrial daytime subject
like sceneries or trees/nature.

I have a 4" 1000mm F/10 Telephoto. I want to get
a digicam that can produce the optimum image
quality. In Astrophography, what we do is get
the resolving power of the scope and get a CCD
with pixel scale that is at least 1/2 of it.
Calculating:

Resolving power of 4" telephoto is 1.16 arcsec
Airy disc linear size of F/10 is 13 micron
that subtends 2.68 arcseconds of the target

Questions.

What do you do in terrestrial photography? Do you
also get pixel scale that is 1/2 the resolving
power of the telephoto? Or do you just match
the pixel size to the airy disc size (in my
case, 13 micron which is the linear diameter
of the airy disc)??

In angular term, one gets the pixel scale
which is 206265 x pixel size/focal length
or 2.68 arcsec/pixel. But since the resolving power
of the telephoto 4" aperture is 1.16 arcsecond...
then 2.68 arcsec/pixel is undersampled. For optimum
sampling, the pixel scale should be at least 0.58
arcsec/pixel or half of the resolving power, at
least in astrophotography. How about in terrestrial
daytime photography? What's the pixel scale?

Hughes

== 2 of 7 ==
Date: Thurs, Apr 23 2009 2:56 am
From: Me

Hughes wrote:
> Hi,
>
> My experience is mostly on astronomical telescopes
> and I now want to view terrestrial daytime subject
> like sceneries or trees/nature.
>
> I have a 4" 1000mm F/10 Telephoto. I want to get
> a digicam that can produce the optimum image
> quality. In Astrophography, what we do is get
> the resolving power of the scope and get a CCD
> with pixel scale that is at least 1/2 of it.
> Calculating:
>
> Resolving power of 4" telephoto is 1.16 arcsec
> Airy disc linear size of F/10 is 13 micron
> that subtends 2.68 arcseconds of the target
>
> Questions.
>
> What do you do in terrestrial photography? Do you
> also get pixel scale that is 1/2 the resolving
> power of the telephoto? Or do you just match
> the pixel size to the airy disc size (in my
> case, 13 micron which is the linear diameter
> of the airy disc)??
>
We have variable apertures, and we tend to buy cameras with the pixel
pitch that the manufacturers happen to churn out. I never heard of
anyone checking available lens resolution figures before buying more
megapixels in the latest camera body - but you do hear the occasional
whine that existing lenses can't match sensor resolution, which is
probably true in some cases.
At normal working apertures with dslrs, sensel size is still well below
double (average wavelength) airy disk size. That's around f11 for APS-c
dslrs with 12mp (or >24mp with 35mm sensor format dslrs with 24mp).
There's generally a small but gradual fall-off in resolution from the
point where average wavelength airy disk is already about sensel size,
but a more prominent resolution loss once 2x sensel size is reached and
exceeded (possibly due to RGBG bayer filter interpolation and
demosaicing methods), hence the notion that many lenses are sharpest at
say f5.6 or f8 though resolution is reduced by inevitable diffraction at
smaller apertures, not by some optical design "fault".
At present pixel densities and with current formats, most reasonable
quality optics can at least resolve (in the centre of the frame) close
to and around theoretical limits at current pixel densities, exceptions
being typical inexpensive long zoom lenses at maximum zoom, and wide
angle lenses - some of which aren't very good toward the edges of the
frame, even stopped down to just below the point where diffraction
really robs resolution. In practice, technique (focus and elimination
of camera shake) are more significant as expectation of final resolution
has increased with higher pixel density cameras.
Small sensor high megapixel "Point and Shoot" cameras are already at or
well beyond the "diffraction limit" at normal working apertures -
particularly at the long end of the zoom range. But the manufacturers
keep churning out models with more and more pixels - because that's
apparently what many people want.

So at f10 (maximum fixed aperture), arguably there wouldn't be much
point going above about 25 megapixels on a 36x24mm sensor for "normal"
photography. But if there are lenses good enough at wider apertures
than f10 (and there most probably are, and will be in future), then
there may be a point in the "megapixel race" going well beyond 50
megapixels for that format.

== 3 of 7 ==
Date: Thurs, Apr 23 2009 3:57 am
From: "N"

"Hughes" <eugenhughes@gmail.com> wrote in message
news:73e6a9a3-3c81-4758-b9da-ebfde76e42c3@c18g2000prh.googlegroups.com...
> Hi,
>
> My experience is mostly on astronomical telescopes
> and I now want to view terrestrial daytime subject
> like sceneries or trees/nature.
>
> I have a 4" 1000mm F/10 Telephoto. I want to get
> a digicam that can produce the optimum image
> quality. In Astrophography, what we do is get
> the resolving power of the scope and get a CCD
> with pixel scale that is at least 1/2 of it.
> Calculating:
>
> Resolving power of 4" telephoto is 1.16 arcsec
> Airy disc linear size of F/10 is 13 micron
> that subtends 2.68 arcseconds of the target
>
> Questions.
>
> What do you do in terrestrial photography? Do you
> also get pixel scale that is 1/2 the resolving
> power of the telephoto? Or do you just match
> the pixel size to the airy disc size (in my
> case, 13 micron which is the linear diameter
> of the airy disc)??
>
> In angular term, one gets the pixel scale
> which is 206265 x pixel size/focal length
> or 2.68 arcsec/pixel. But since the resolving power
> of the telephoto 4" aperture is 1.16 arcsecond...
> then 2.68 arcsec/pixel is undersampled. For optimum
> sampling, the pixel scale should be at least 0.58
> arcsec/pixel or half of the resolving power, at
> least in astrophotography. How about in terrestrial
> daytime photography? What's the pixel scale?
>
>
> Hughes

I tend to consider the subject matter, composition, lighting and then what I
might do with the resulting picture. I might print it, frame it and hang it
on the wall or give it to someone to keep or just keep it on file.

Until you get a camera and take pictures all the theory in the world is
worth nothing.

== 4 of 7 ==
Date: Thurs, Apr 23 2009 4:03 am
From: Hughes

On Apr 23, 5:56 pm, Me <u...@domain.invalid> wrote:
> Hughes wrote:
> > Hi,
>
> > My experience is mostly on astronomical telescopes
> > and I now want to view terrestrial daytime subject
> > like sceneries or trees/nature.
>
> > I have a 4" 1000mm F/10 Telephoto. I want to get
> > a digicam that can produce the optimum image
> > quality. In Astrophography, what we do is get
> > the resolving power of the scope and get a CCD
> > with pixel scale that is at least 1/2 of it.
> > Calculating:
>
> > Resolving power of 4" telephoto is 1.16 arcsec
> > Airy disc linear size of F/10 is 13 micron
> > that subtends 2.68 arcseconds of the target
>
> > Questions.
>
> > What do you do in terrestrial photography? Do you
> > also get pixel scale that is 1/2 the resolving
> > power of the telephoto? Or do you just match
> > the pixel size to the airy disc size (in my
> > case, 13 micron which is the linear diameter
> > of the airy disc)??
>
> >
> We have variable apertures, and we tend to buy cameras with the pixel
> pitch that the manufacturers happen to churn out. I never heard of
> anyone checking available lens resolution figures before buying more
> megapixels in the latest camera body - but you do hear the occasional
> whine that existing lenses can't match sensor resolution, which is
> probably true in some cases.
> At normal working apertures with dslrs, sensel size is still well below
> double (average wavelength) airy disk size. That's around f11 for APS-c
> dslrs with 12mp (or >24mp with 35mm sensor format dslrs with 24mp).
> There's generally a small but gradual fall-off in resolution from the
> point where average wavelength airy disk is already about sensel size,
> but a more prominent resolution loss once 2x sensel size is reached and
> exceeded (possibly due to RGBG bayer filter interpolation and
> demosaicing methods), hence the notion that many lenses are sharpest at
> say f5.6 or f8 though resolution is reduced by inevitable diffraction at
> smaller apertures, not by some optical design "fault".
> At present pixel densities and with current formats, most reasonable
> quality optics can at least resolve (in the centre of the frame) close
> to and around theoretical limits at current pixel densities, exceptions
> being typical inexpensive long zoom lenses at maximum zoom, and wide
> angle lenses - some of which aren't very good toward the edges of the
> frame, even stopped down to just below the point where diffraction
> really robs resolution. In practice, technique (focus and elimination
> of camera shake) are more significant as expectation of final resolution
> has increased with higher pixel density cameras.
> Small sensor high megapixel "Point and Shoot" cameras are already at or
> well beyond the "diffraction limit" at normal working apertures -
> particularly at the long end of the zoom range. But the manufacturers
> keep churning out models with more and more pixels - because that's
> apparently what many people want.
>
> So at f10 (maximum fixed aperture), arguably there wouldn't be much
> point going above about 25 megapixels on a 36x24mm sensor for "normal"
> photography. But if there are lenses good enough at wider apertures
> than f10 (and there most probably are, and will be in future), then
> there may be a point in the "megapixel race" going well beyond 50
> megapixels for that format.- Hide quoted text -
>
> - Show quoted text -

I plan to buy a Canon 1000D. Calculating the pixel
scale of the 1000mm telephoto f/10:

pixel scale = 206265 x 5.7 micron/1000
pixel scale = 1.175 arcsec/pixel
resolving power of telephoto is 1.16 arcsec
airy disc subtended is 2.68 arcsec

In terrestrial photography, do you admit that we
shouldn't aim to match the resolving power of
the telephoto but the airy disc size itself or
its average diffraction rings. If so, then the 1000D
is oversampling already?

If I get a used Canon 300D, the pixel scale is
206265 x 0.0074/1000= 1.5 arcsec/pixel, which is
about optimally sampled?

But here's a complication. My telephoto is a mirror
or mak, central light of airy disc is pumped to the
diffraction rings. Add to it is possible wavefront
error of 1/3 wave, then my airy disc is twice the
size so it's about 26 micron or subtending 5.3
arcsecond. So I think I must get a camera
with pixel size of at least 11 micron? Resolution
there can be lower than 5 megapixel (this
means if my telephoto, increasing the megapixel
wouldn't produce better image, but just magnifying
all the defects).

I'm calculating what is the theoretical pixel pitch
I should get for my 1000mm f/10 fixed aperture telephoto where
decreasing its size wouldn't
produce improvement in quality. Note this is for
theoretical exploration and to better understand
the optical concept of telephoto and sensor sizes
and their optimum matching depending on target
structures.

Hughes

== 5 of 7 ==
Date: Thurs, Apr 23 2009 4:27 am
From: Me

Hughes wrote:
> On Apr 23, 5:56 pm, Me <u...@domain.invalid> wrote:
>> Hughes wrote:
>>> Hi,
>>> My experience is mostly on astronomical telescopes
>>> and I now want to view terrestrial daytime subject
>>> like sceneries or trees/nature.
>>> I have a 4" 1000mm F/10 Telephoto. I want to get
>>> a digicam that can produce the optimum image
>>> quality. In Astrophography, what we do is get
>>> the resolving power of the scope and get a CCD
>>> with pixel scale that is at least 1/2 of it.
>>> Calculating:
>>> Resolving power of 4" telephoto is 1.16 arcsec
>>> Airy disc linear size of F/10 is 13 micron
>>> that subtends 2.68 arcseconds of the target
>>> Questions.
>>> What do you do in terrestrial photography? Do you
>>> also get pixel scale that is 1/2 the resolving
>>> power of the telephoto? Or do you just match
>>> the pixel size to the airy disc size (in my
>>> case, 13 micron which is the linear diameter
>>> of the airy disc)??
>> >
>> We have variable apertures, and we tend to buy cameras with the pixel
>> pitch that the manufacturers happen to churn out. I never heard of
>> anyone checking available lens resolution figures before buying more
>> megapixels in the latest camera body - but you do hear the occasional
>> whine that existing lenses can't match sensor resolution, which is
>> probably true in some cases.
>> At normal working apertures with dslrs, sensel size is still well below
>> double (average wavelength) airy disk size. That's around f11 for APS-c
>> dslrs with 12mp (or >24mp with 35mm sensor format dslrs with 24mp).
>> There's generally a small but gradual fall-off in resolution from the
>> point where average wavelength airy disk is already about sensel size,
>> but a more prominent resolution loss once 2x sensel size is reached and
>> exceeded (possibly due to RGBG bayer filter interpolation and
>> demosaicing methods), hence the notion that many lenses are sharpest at
>> say f5.6 or f8 though resolution is reduced by inevitable diffraction at
>> smaller apertures, not by some optical design "fault".
>> At present pixel densities and with current formats, most reasonable
>> quality optics can at least resolve (in the centre of the frame) close
>> to and around theoretical limits at current pixel densities, exceptions
>> being typical inexpensive long zoom lenses at maximum zoom, and wide
>> angle lenses - some of which aren't very good toward the edges of the
>> frame, even stopped down to just below the point where diffraction
>> really robs resolution. In practice, technique (focus and elimination
>> of camera shake) are more significant as expectation of final resolution
>> has increased with higher pixel density cameras.
>> Small sensor high megapixel "Point and Shoot" cameras are already at or
>> well beyond the "diffraction limit" at normal working apertures -
>> particularly at the long end of the zoom range. But the manufacturers
>> keep churning out models with more and more pixels - because that's
>> apparently what many people want.
>>
>> So at f10 (maximum fixed aperture), arguably there wouldn't be much
>> point going above about 25 megapixels on a 36x24mm sensor for "normal"
>> photography. But if there are lenses good enough at wider apertures
>> than f10 (and there most probably are, and will be in future), then
>> there may be a point in the "megapixel race" going well beyond 50
>> megapixels for that format.- Hide quoted text -
>>
>> - Show quoted text -
>
> I plan to buy a Canon 1000D. Calculating the pixel
> scale of the 1000mm telephoto f/10:
>
> pixel scale = 206265 x 5.7 micron/1000
> pixel scale = 1.175 arcsec/pixel
> resolving power of telephoto is 1.16 arcsec
> airy disc subtended is 2.68 arcsec
>
> In terrestrial photography, do you admit that we
> shouldn't aim to match the resolving power of
> the telephoto but the airy disc size itself or
> its average diffraction rings. If so, then the 1000D
> is oversampling already?
>
> If I get a used Canon 300D, the pixel scale is
> 206265 x 0.0074/1000= 1.5 arcsec/pixel, which is
> about optimally sampled?
>
> But here's a complication. My telephoto is a mirror
> or mak, central light of airy disc is pumped to the
> diffraction rings. Add to it is possible wavefront
> error of 1/3 wave, then my airy disc is twice the
> size so it's about 26 micron or subtending 5.3
> arcsecond. So I think I must get a camera
> with pixel size of at least 11 micron? Resolution
> there can be lower than 5 megapixel (this
> means if my telephoto, increasing the megapixel
> wouldn't produce better image, but just magnifying
> all the defects).
>
> I'm calculating what is the theoretical pixel pitch
> I should get for my 1000mm f/10 fixed aperture telephoto where
> decreasing its size wouldn't
> produce improvement in quality. Note this is for
> theoretical exploration and to better understand
> the optical concept of telephoto and sensor sizes
> and their optimum matching depending on target
> structures.
>
> Hughes
>
I'd say forget the "waste" of oversampling.
I'd expect a newer Canon dslr sensor to have lower read noise and higher
quantum efficiency than an older Canon DSLR. I'd also expect a higher
end Canon dslr (ie 40d or 50d) to have lower read noise than a digital
rebel model with the same pixel count and density, as that's the way it
seems to have worked in the past when raw data has been analysed. Canon
seem to cheapen out the sensors and support electronics on the lower
models - for normal photography there's actually not a lot of
difference, but there might be for you.
It might be ideal if Canon made a new 6 megapixel APS-c sensor dslr, but
they haven't done so for years now, and sensor technology has moved on
quite a lot over that time - since the 300d. Some terrestrial
photographers would be happy if they did make some lower pixel count
models, but that opens up an argument that's a can of worms.
But I suggest you ask further questions on specific astrophotography
sites. Sorry I can't offer links, but I've seen sites where dslr
performance for astrophotography is tested very thoroughly by
enthusiasts who are very quick to check out new models as soon as they
can get their hands on them.

== 6 of 7 ==
Date: Thurs, Apr 23 2009 5:02 am
From: Hughes

On Apr 23, 7:27 pm, Me <u...@domain.invalid> wrote:
> Hughes wrote:
> > On Apr 23, 5:56 pm, Me <u...@domain.invalid> wrote:
> >> Hughes wrote:
> >>> Hi,
> >>> My experience is mostly on astronomical telescopes
> >>> and I now want to view terrestrial daytime subject
> >>> like sceneries or trees/nature.
> >>> I have a 4" 1000mm F/10 Telephoto. I want to get
> >>> a digicam that can produce the optimum image
> >>> quality. In Astrophography, what we do is get
> >>> the resolving power of the scope and get a CCD
> >>> with pixel scale that is at least 1/2 of it.
> >>> Calculating:
> >>> Resolving power of 4" telephoto is 1.16 arcsec
> >>> Airy disc linear size of F/10 is 13 micron
> >>> that subtends 2.68 arcseconds of the target
> >>> Questions.
> >>> What do you do in terrestrial photography? Do you
> >>> also get pixel scale that is 1/2 the resolving
> >>> power of the telephoto? Or do you just match
> >>> the pixel size to the airy disc size (in my
> >>> case, 13 micron which is the linear diameter
> >>> of the airy disc)??
>
> >> We have variable apertures, and we tend to buy cameras with the pixel
> >> pitch that the manufacturers happen to churn out. I never heard of
> >> anyone checking available lens resolution figures before buying more
> >> megapixels in the latest camera body - but you do hear the occasional
> >> whine that existing lenses can't match sensor resolution, which is
> >> probably true in some cases.
> >> At normal working apertures with dslrs, sensel size is still well below
> >> double (average wavelength) airy disk size. That's around f11 for APS-c
> >> dslrs with 12mp (or >24mp with 35mm sensor format dslrs with 24mp).
> >> There's generally a small but gradual fall-off in resolution from the
> >> point where average wavelength airy disk is already about sensel size,
> >> but a more prominent resolution loss once 2x sensel size is reached and
> >> exceeded (possibly due to RGBG bayer filter interpolation and
> >> demosaicing methods), hence the notion that many lenses are sharpest at
> >> say f5.6 or f8 though resolution is reduced by inevitable diffraction at
> >> smaller apertures, not by some optical design "fault".
> >> At present pixel densities and with current formats, most reasonable
> >> quality optics can at least resolve (in the centre of the frame) close
> >> to and around theoretical limits at current pixel densities, exceptions
> >> being typical inexpensive long zoom lenses at maximum zoom, and wide
> >> angle lenses - some of which aren't very good toward the edges of the
> >> frame, even stopped down to just below the point where diffraction
> >> really robs resolution. In practice, technique (focus and elimination
> >> of camera shake) are more significant as expectation of final resolution
> >> has increased with higher pixel density cameras.
> >> Small sensor high megapixel "Point and Shoot" cameras are already at or
> >> well beyond the "diffraction limit" at normal working apertures -
> >> particularly at the long end of the zoom range. But the manufacturers
> >> keep churning out models with more and more pixels - because that's
> >> apparently what many people want.
>
> >> So at f10 (maximum fixed aperture), arguably there wouldn't be much
> >> point going above about 25 megapixels on a 36x24mm sensor for "normal"
> >> photography. But if there are lenses good enough at wider apertures
> >> than f10 (and there most probably are, and will be in future), then
> >> there may be a point in the "megapixel race" going well beyond 50
> >> megapixels for that format.- Hide quoted text -
>
> >> - Show quoted text -
>
> > I plan to buy a Canon 1000D. Calculating the pixel
> > scale of the 1000mm telephoto f/10:
>
> > pixel scale = 206265 x 5.7 micron/1000
> > pixel scale = 1.175 arcsec/pixel
> > resolving power of telephoto is 1.16 arcsec
> > airy disc subtended is 2.68 arcsec
>
> > In terrestrial photography, do you admit that we
> > shouldn't aim to match the resolving power of
> > the telephoto but the airy disc size itself or
> > its average diffraction rings. If so, then the 1000D
> > is oversampling already?
>
> > If I get a used Canon 300D, the pixel scale is
> > 206265 x 0.0074/1000= 1.5 arcsec/pixel, which is
> > about optimally sampled?
>
> > But here's a complication. My telephoto is a mirror
> > or mak, central light of airy disc is pumped to the
> > diffraction rings. Add to it is possible wavefront
> > error of 1/3 wave, then my airy disc is twice the
> > size so it's about 26 micron or subtending 5.3
> > arcsecond. So I think I must get a camera
> > with pixel size of at least 11 micron? Resolution
> > there can be lower than 5 megapixel (this
> > means if my telephoto, increasing the megapixel
> > wouldn't produce better image, but just magnifying
> > all the defects).
>
> > I'm calculating what is the theoretical pixel pitch
> > I should get for my 1000mm f/10 fixed aperture telephoto where
> > decreasing its size wouldn't
> > produce improvement in quality. Note this is for
> > theoretical exploration and to better understand
> > the optical concept of telephoto and sensor sizes
> > and their optimum matching depending on target
> > structures.
>
> > Hughes
>
> I'd say forget the "waste" of oversampling.
> I'd expect a newer Canon dslr sensor to have lower read noise and higher
> quantum efficiency than an older Canon DSLR. I'd also expect a higher
> end Canon dslr (ie 40d or 50d) to have lower read noise than a digital
> rebel model with the same pixel count and density, as that's the way it
> seems to have worked in the past when raw data has been analysed. Canon
> seem to cheapen out the sensors and support electronics on the lower
> models - for normal photography there's actually not a lot of
> difference, but there might be for you.
> It might be ideal if Canon made a new 6 megapixel APS-c sensor dslr, but
> they haven't done so for years now, and sensor technology has moved on
> quite a lot over that time - since the 300d. Some terrestrial
> photographers would be happy if they did make some lower pixel count
> models, but that opens up an argument that's a can of worms.
> But I suggest you ask further questions on specific astrophotography
> sites. Sorry I can't offer links, but I've seen sites where dslr
> performance for astrophotography is tested very thoroughly by
> enthusiasts who are very quick to check out new models as soon as they
> can get their hands on them.- Hide quoted text -
>
> - Show quoted text -

I won't be using it on astrophotography. I'd use it only
terrestrially to image flowers, bees, trees, etc.
So astrophotographers can't answer my questions
because their only concern are the stars and
nothing more. My main question is simply this.
First resolving power is not the same as airy
disc size. Resolving power is smaller. For example,
in my 4" aperture f/10 telephoto. Resolving power
is 1.16 arcsecond while the airy disc is 2.68
arcsecond. Now should my pixel be based
on resolving power or airy disc size?
What's the norm or rule-of-thumb in photography?
Should it be 1/2 the size of the resolving power
or 1/2 the size of the airy disc?? This is simply what
I wanted to know. Astrophotographers mostly haven't viewed
terrestrially so can't answer the question. Now
you photographers and optical specialists might. Thanks.

Hughes

== 7 of 7 ==
Date: Thurs, Apr 23 2009 6:18 am
From: Me

Hughes wrote:
> On Apr 23, 7:27 pm, Me <u...@domain.invalid> wrote:
>> Hughes wrote:
>>> On Apr 23, 5:56 pm, Me <u...@domain.invalid> wrote:
>>>> Hughes wrote:
>>>>> Hi,
>>>>> My experience is mostly on astronomical telescopes
>>>>> and I now want to view terrestrial daytime subject
>>>>> like sceneries or trees/nature.
>>>>> I have a 4" 1000mm F/10 Telephoto. I want to get
>>>>> a digicam that can produce the optimum image
>>>>> quality. In Astrophography, what we do is get
>>>>> the resolving power of the scope and get a CCD
>>>>> with pixel scale that is at least 1/2 of it.
>>>>> Calculating:
>>>>> Resolving power of 4" telephoto is 1.16 arcsec
>>>>> Airy disc linear size of F/10 is 13 micron
>>>>> that subtends 2.68 arcseconds of the target
>>>>> Questions.
>>>>> What do you do in terrestrial photography? Do you
>>>>> also get pixel scale that is 1/2 the resolving
>>>>> power of the telephoto? Or do you just match
>>>>> the pixel size to the airy disc size (in my
>>>>> case, 13 micron which is the linear diameter
>>>>> of the airy disc)??
>>>> We have variable apertures, and we tend to buy cameras with the pixel
>>>> pitch that the manufacturers happen to churn out. I never heard of
>>>> anyone checking available lens resolution figures before buying more
>>>> megapixels in the latest camera body - but you do hear the occasional
>>>> whine that existing lenses can't match sensor resolution, which is
>>>> probably true in some cases.
>>>> At normal working apertures with dslrs, sensel size is still well below
>>>> double (average wavelength) airy disk size. That's around f11 for APS-c
>>>> dslrs with 12mp (or >24mp with 35mm sensor format dslrs with 24mp).
>>>> There's generally a small but gradual fall-off in resolution from the
>>>> point where average wavelength airy disk is already about sensel size,
>>>> but a more prominent resolution loss once 2x sensel size is reached and
>>>> exceeded (possibly due to RGBG bayer filter interpolation and
>>>> demosaicing methods), hence the notion that many lenses are sharpest at
>>>> say f5.6 or f8 though resolution is reduced by inevitable diffraction at
>>>> smaller apertures, not by some optical design "fault".
>>>> At present pixel densities and with current formats, most reasonable
>>>> quality optics can at least resolve (in the centre of the frame) close
>>>> to and around theoretical limits at current pixel densities, exceptions
>>>> being typical inexpensive long zoom lenses at maximum zoom, and wide
>>>> angle lenses - some of which aren't very good toward the edges of the
>>>> frame, even stopped down to just below the point where diffraction
>>>> really robs resolution. In practice, technique (focus and elimination
>>>> of camera shake) are more significant as expectation of final resolution
>>>> has increased with higher pixel density cameras.
>>>> Small sensor high megapixel "Point and Shoot" cameras are already at or
>>>> well beyond the "diffraction limit" at normal working apertures -
>>>> particularly at the long end of the zoom range. But the manufacturers
>>>> keep churning out models with more and more pixels - because that's
>>>> apparently what many people want.
>>>> So at f10 (maximum fixed aperture), arguably there wouldn't be much
>>>> point going above about 25 megapixels on a 36x24mm sensor for "normal"
>>>> photography. But if there are lenses good enough at wider apertures
>>>> than f10 (and there most probably are, and will be in future), then
>>>> there may be a point in the "megapixel race" going well beyond 50
>>>> megapixels for that format.- Hide quoted text -
>>>> - Show quoted text -
>>> I plan to buy a Canon 1000D. Calculating the pixel
>>> scale of the 1000mm telephoto f/10:
>>> pixel scale = 206265 x 5.7 micron/1000
>>> pixel scale = 1.175 arcsec/pixel
>>> resolving power of telephoto is 1.16 arcsec
>>> airy disc subtended is 2.68 arcsec
>>> In terrestrial photography, do you admit that we
>>> shouldn't aim to match the resolving power of
>>> the telephoto but the airy disc size itself or
>>> its average diffraction rings. If so, then the 1000D
>>> is oversampling already?
>>> If I get a used Canon 300D, the pixel scale is
>>> 206265 x 0.0074/1000= 1.5 arcsec/pixel, which is
>>> about optimally sampled?
>>> But here's a complication. My telephoto is a mirror
>>> or mak, central light of airy disc is pumped to the
>>> diffraction rings. Add to it is possible wavefront
>>> error of 1/3 wave, then my airy disc is twice the
>>> size so it's about 26 micron or subtending 5.3
>>> arcsecond. So I think I must get a camera
>>> with pixel size of at least 11 micron? Resolution
>>> there can be lower than 5 megapixel (this
>>> means if my telephoto, increasing the megapixel
>>> wouldn't produce better image, but just magnifying
>>> all the defects).
>>> I'm calculating what is the theoretical pixel pitch
>>> I should get for my 1000mm f/10 fixed aperture telephoto where
>>> decreasing its size wouldn't
>>> produce improvement in quality. Note this is for
>>> theoretical exploration and to better understand
>>> the optical concept of telephoto and sensor sizes
>>> and their optimum matching depending on target
>>> structures.
>>> Hughes
>> I'd say forget the "waste" of oversampling.
>> I'd expect a newer Canon dslr sensor to have lower read noise and higher
>> quantum efficiency than an older Canon DSLR. I'd also expect a higher
>> end Canon dslr (ie 40d or 50d) to have lower read noise than a digital
>> rebel model with the same pixel count and density, as that's the way it
>> seems to have worked in the past when raw data has been analysed. Canon
>> seem to cheapen out the sensors and support electronics on the lower
>> models - for normal photography there's actually not a lot of
>> difference, but there might be for you.
>> It might be ideal if Canon made a new 6 megapixel APS-c sensor dslr, but
>> they haven't done so for years now, and sensor technology has moved on
>> quite a lot over that time - since the 300d. Some terrestrial
>> photographers would be happy if they did make some lower pixel count
>> models, but that opens up an argument that's a can of worms.
>> But I suggest you ask further questions on specific astrophotography
>> sites. Sorry I can't offer links, but I've seen sites where dslr
>> performance for astrophotography is tested very thoroughly by
>> enthusiasts who are very quick to check out new models as soon as they
>> can get their hands on them.- Hide quoted text -
>>
>> - Show quoted text -
>
> I won't be using it on astrophotography. I'd use it only
> terrestrially to image flowers, bees, trees, etc.
> So astrophotographers can't answer my questions
> because their only concern are the stars and
> nothing more. My main question is simply this.
> First resolving power is not the same as airy
> disc size. Resolving power is smaller. For example,
> in my 4" aperture f/10 telephoto. Resolving power
> is 1.16 arcsecond while the airy disc is 2.68
> arcsecond. Now should my pixel be based
> on resolving power or airy disc size?
> What's the norm or rule-of-thumb in photography?
> Should it be 1/2 the size of the resolving power
> or 1/2 the size of the airy disc?? This is simply what
> I wanted to know. Astrophotographers mostly haven't viewed
> terrestrially so can't answer the question. Now
> you photographers and optical specialists might. Thanks.
>
> Hughes

Okay - I don't "get" what you're saying with your airy disk definition.
At f10 with any normal camera lens, the central peak is (only) about
11 or 12 microns, and it seems that this central peak diameter is what
matters most. At 6 um sensel "pixel" size (about 10mp on APS-c) airy
disk diameter of 11 microns on the verge of being diffraction limited,
you'll be fine with a Canon 1000d pixel density, but going over this
only means you get bigger files with little or no resolution gain. Same
as if your effective airy disk diameter is larger, then there mightn't
be any gain from 10 mp over 5, but you don't lose anything except extra
file size. Overall noise performance has improved along with and
despite higher pixel counts so far and in most cases.
You can't get a (new) low cost dslr with close to 11um pixels.
Nikon's 12mp D700 (or Canon's original 5d Mk 1) has the largest pixels,
but 36x24mm sensor, and they are not at the budget end.
Sigma's Foveon sensor dslrs have large pixels (about 5mp and APS-c
size), but crappy (TM) high ISO performance, and that's what you're
probably going to need.
At 1000mm holding it steady enough won't be easy. At longer distances,
atmospheric effects will likely degrade resolution. Forget "optimally
sampled" and go for a model with good low noise high ISO performance and
other features you need. Make sure the model you get has mirror lock-up.
Some basic dslrs don't have this, and at 1000mm mirror slap will be a
real issue.

==============================================================================
TOPIC: New Portugese convertible !!!!
http://groups.google.com/group/rec.photo.digital/t/82d9d8b041ec3d8c?hl=en
==============================================================================

== 1 of 1 ==
Date: Thurs, Apr 23 2009 3:53 am
From: Bruce

"Frank ess" <frank@fshe2fs.com> wrote:
>Bruce wrote:
>> "Frank ess" <frank@fshe2fs.com> wrote:
>>> Bruce wrote:
>>>> "Frank ess" <frank@fshe2fs.com> wrote:
>>>>> Bruce wrote:
>>>>>> Paul Giverin <paul@giverin.co.uk> wrote:
>>>>>>> In message <N6ednUn8YIsgyHPUnZ2dnUVZ8gidnZ2d@novis.pt>, Focus
>>>>>>> <dont@mail.me> writes
>>>>>>>> 70 MPG
>>>>>>>> http://caldasdarainha.olx.pt/magalhaes-movel-iid-16058871
>>>>>>>> ;-)
>>>>>>> Do you really have to cross post this shite to all these
>>>>>>> groups?
>>>>>>
>>>>>>
>>>>>> Does he ever post anything else?
>>>>>
>>>>> I dono. I never look at them.
>>>>>
>>>>> It's nice that you both left the URL unmolested, so others could
>>>>> judge for themselves. Very considerate. Equitable, even.
>>>>
>>>>
>>>> My pleasure, Frank.
>>>>
>>>> A minor detail: No-one forced you to click on the link. ;-)
>>>
>>> You got the "minor" wrong; did you read where I didn't ever look at
>>> them? ... "never", "ever", pretty difficult to make the
>>> conversion, eh?
>>
>>
>> I couldn't find "dono" in the dictionary so I gave up reading after
>> that. ;-)
>
>A freaking lie on the face of it.
>
>Buh bye.

I couldn't find "Buh" in the dictionary so I gave up reading after
that. ;-)

==============================================================================
TOPIC: Why DSLR mirrors must eventually go
http://groups.google.com/group/rec.photo.digital/t/68febc4ea5622551?hl=en
==============================================================================

== 1 of 2 ==
Date: Thurs, Apr 23 2009 4:23 am
From: "Matt Clara"

"jdear" <jdear64@yahoo.com> wrote in message
news:80926480-8d81-44a8-b7ab-8c83ee865620@g1g2000yqh.googlegroups.com...
On Apr 21, 9:29 pm, "David J. Littleboy" <davi...@gol.com> wrote:
> "Matt Clara" <n...@myexpense.com> wrote:
> > "David J. Littleboy" <davi...@gol.com> wrote:
>
> >>> Instead of MLU? Live View does not in and of itself reduce mirror
> >>> shock, does it? Or did you tear the mirror out of your DSLR so you
> >>> won't have to deal with it?
>
> >> You must be a Nikon user. When you take a shot in live view mode on a
> >> Canon camera, the mirror stays up and there is no mirror slap. Oops.
> >> Nikon gets something seriously wrong.
>
> > Is it possible to use Nikon's live vue in conjunction with MLU, or does
> > Nikon's live vue equal no possibility of MLU at all? If not, that would
> > be a serious flaw indeed.
>
> I don't know: that's something I read from a Nikon user here.
>
> Apparently the Nikons flop the mirror down to do an AF. Maybe if AF were
> turned off they'd do the right thing.
>
> --
> David J. Littleboy
> Tokyo, Japan

What about exposure? If the mirror doesn't come down, the exposure
will
have to be either set manually or the last EV taken used ( which may
now
be incorrect because the scene changed ). True?

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Why ask him, he doesn't know.

== 2 of 2 ==
Date: Thurs, Apr 23 2009 5:23 am
From: Chris Malcolm

In rec.photo.digital.slr-systems jdear <jdear64@yahoo.com> wrote:
> On Apr 21, 9:29?pm, "David J. Littleboy" <davi...@gol.com> wrote:
>> "Matt Clara" <n...@myexpense.com> wrote:
>> > "David J. Littleboy" <davi...@gol.com> wrote:
>>
>> >>> Instead of MLU? ?Live View does not in and of itself reduce mirror
>> >>> shock, does it? ?Or did you tear the mirror out of your DSLR so you
>> >>> won't have to deal with it?
>>
>> >> You must be a Nikon user. When you take a shot in live view mode on a
>> >> Canon camera, the mirror stays up and there is no mirror slap. Oops.
>> >> Nikon gets something seriously wrong.
>>
>> > Is it possible to use Nikon's live vue in conjunction with MLU, or does
>> > Nikon's live vue equal no possibility of MLU at all? ?If not, that would
>> > be a serious flaw indeed.
>>
>> I don't know: that's something I read from a Nikon user here.
>>
>> Apparently the Nikons flop the mirror down to do an AF. Maybe if AF were
>> turned off they'd do the right thing.
>>
>> --
>> David J. Littleboy
>> Tokyo, Japan

> What about exposure? If the mirror doesn't come down, the exposure
> will
> have to be either set manually or the last EV taken used ( which may
> now
> be incorrect because the scene changed ). True?

Not necessarily, because since the camera is currently reading the
live view sensor, it could use that to calculate exposure, and if it
was in matrix or wide view whatever exposure mode, it could calculate
exposure more accurately than with the array of exposure sensors it
uses in mirror down mode, because it now in effect has millions of
exposure sensors to select from.

Whether the makers of any particular DLSR with live view bothered to
write the code to take advantage of that possibility is another
question. Sony certainly did, so on those models the live view matrix
mode exposure is the most accurate.

--
Chris Malcolm

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