Wednesday, April 22, 2009

rec.photo.digital - 25 new messages in 7 topics - digest

rec.photo.digital
http://groups.google.com/group/rec.photo.digital?hl=en

rec.photo.digital@googlegroups.com

Today's topics:

* Canon DSLR Live View - 6 messages, 5 authors
http://groups.google.com/group/rec.photo.digital/t/21ca0cd9457ba13c?hl=en
* New Mandate: Punography - 4 messages, 3 authors
http://groups.google.com/group/rec.photo.digital/t/e22297df98c46fc4?hl=en
* New Portugese convertible !!!! - 5 messages, 3 authors
http://groups.google.com/group/rec.photo.digital/t/82d9d8b041ec3d8c?hl=en
* Are todays LCD screen any good in bright weather - 2 messages, 2 authors
http://groups.google.com/group/rec.photo.digital/t/d70e4ce3863b627f?hl=en
* Why DSLR mirrors must eventually go - 3 messages, 3 authors
http://groups.google.com/group/rec.photo.digital/t/68febc4ea5622551?hl=en
* Focus Confirmation - 4 messages, 2 authors
http://groups.google.com/group/rec.photo.digital/t/e4cdfb75a347ac36?hl=en
* Great forum! - 1 messages, 1 author
http://groups.google.com/group/rec.photo.digital/t/ac2220a39a1c052b?hl=en

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

== 1 of 6 ==
Date: Wed, Apr 22 2009 12:08 pm
From: Chris Malcolm


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?

Why don't the previous DSLRs with live view LCD count as "making this
feature available"?

--
Chris Malcolm

== 2 of 6 ==
Date: Wed, Apr 22 2009 2:28 pm
From: Doug Jewell


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. 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.


== 3 of 6 ==
Date: Wed, Apr 22 2009 3:21 pm
From: Eugene


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

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 -

== 4 of 6 ==
Date: Wed, Apr 22 2009 3:21 pm
From: "Charles"

"nospam" <nospam@nospam.invalid> wrote in message
news:220420091213314368%nospam@nospam.invalid...
> In article
> <41013a87-9d0e-40e2-8d30-a673c2687c23@x5g2000yqk.googlegroups.com>, Pat
> <groups@artisticphotography.us> 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!


== 5 of 6 ==
Date: Wed, Apr 22 2009 3:42 pm
From: "Dudley Hanks"

"Charles" <charlesschuler@comcast.net> wrote in message
news:gso59n$qdn$1@news.motzarella.org...
>
> "nospam" <nospam@nospam.invalid> wrote in message
> news:220420091213314368%nospam@nospam.invalid...
>> In article
>> <41013a87-9d0e-40e2-8d30-a673c2687c23@x5g2000yqk.googlegroups.com>, Pat
>> <groups@artisticphotography.us> 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!
>

Also, the LV focus can focus in lower lighting situations where the normal,
or Quick Focus, has problems. I know that won't carry a lot of weight,
since it comes from somebody who has problems getting the focus where he
wants it, but, it does seem to have a lower operating threshold.

So, that 1,000 mm lens sitting on the tripod might benefit from LV, even on
a sunny day, and even if you can see the image, yourself, better through the
viewfinder. The camera might see it better with LV -- especially if you
plop a 2X converter on it and cut the aperture in half.

Take Care,
Dudley


== 6 of 6 ==
Date: Wed, Apr 22 2009 4:32 pm
From: Eugene


On Apr 23, 6:42 am, "Dudley Hanks" <dha...@blind-apertures.ca> wrote:
> "Charles" <charlesschu...@comcast.net> wrote in message
>
> news:gso59n$qdn$1@news.motzarella.org...
>
>
>
>
>
>
>
> > "nospam" <nos...@nospam.invalid> wrote in message
> >news:220420091213314368%nospam@nospam.invalid...
> >> In article
> >> <41013a87-9d0e-40e2-8d30-a673c2687...@x5g2000yqk.googlegroups.com>, Pat
> >> <gro...@artisticphotography.us> 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!
>
> Also, the LV focus can focus in lower lighting situations where the normal,
> or Quick Focus, has problems.  I know that won't carry a lot of weight,
> since it comes from somebody who has problems getting the focus where he
> wants it, but, it does seem to have a lower operating threshold.

Has anyone tried F/10 with the LiveView by using teleconverter
with say a 400mm telephoto? How is the image? How
is Contrast Autofocus.. Can it still focus? (I assume Phase
Detection no longer works with F/10 even in Live View).
Also does Manual focusing guarantee to work by
zooming in on the object for more accurate manual
focusing (if it is bright enough in the first place to
zoom in).

>
> So, that 1,000 mm lens sitting on the tripod might benefit from LV, even on
> a sunny day, and even if you can see the image, yourself, better through the
> viewfinder.  The camera might see it better with LV -- especially if you
> plop a 2X converter on it and cut the aperture in half.

A 2X converter would make the 1000mm lens 2000mm.
It won't cut the aperture in half but just extend the focal
length.

E

>
> Take Care,
> Dudley- Hide quoted text -
>
> - Show quoted text -


==============================================================================
TOPIC: New Mandate: Punography
http://groups.google.com/group/rec.photo.digital/t/e22297df98c46fc4?hl=en
==============================================================================

== 1 of 4 ==
Date: Wed, Apr 22 2009 12:34 pm
From: "Frank ess"


Chris Malcolm wrote:
> In rec.photo.digital.slr-systems Bill Graham <weg9@comcast.net>
> wrote:
>
>> "Frank ess" <frank@fshe2fs.com> wrote in message
>> news:GL2dnfCROt7f0HDUnZ2dnUVZ_r-dnZ2d@giganews.com...
>>>
>>> STILL guess I need to have someone show me an example of a visual
>>> pun that does not depend on words.
>
>> Isn't the definition of a pun a "play on words"? - If it is, then
>> a pun that doesn't depend on words would be impossible.
>
> I think you're missing that important feature of human natural
> language which allows the meanings of words to be extended. That's
> why for example we can talk of cameras having a family resemblance
> even though cameras don't have families, why we can talk of high
> contrast even though it's no higher off the ground than low
> contrast, and so on. And why we can talk of visual puns.

WTF is "human natural language"? Language is not natural. It's an
artefact of natural processes.

My Philosophy of Science professor, Dr Harrah, used to speak of "The
largest glacier in Riverside (California) County. There am no such
animal.

That's cool, talking of visual puns.

I need someone to show me one.

--
Frank ess

== 2 of 4 ==
Date: Wed, Apr 22 2009 12:35 pm
From: "Frank ess"


whisky-dave wrote:
> "Alan Browne" <alan.browne@Freelunchvideotron.ca> wrote in message
> news:1cmdnWDBi86tlXDUnZ2dnUVZ_jWdnZ2d@giganews.com...
>> Leon@here.com wrote:
>>
>>> and the word 'pussy' is used for the same thing even in French.
>>> I've heard the
>>> word 'chat' used in France to describe a womans....!
>>
>> Chatte, actually. (feminine of chat) or "Minou".
>>
>> With Minou being the more acceptable 'slang' and
>> 'chatte' being the obscene.
>
> I thought it was chat because French women can't stop talking :)
>
>
> Although that's rather unfair, I mean isn't it that all women can;t
> stop talking ;-)

I think they can, just don't know when to.

(Shut UP, he explained)

--
Frank ess


== 3 of 4 ==
Date: Wed, Apr 22 2009 2:02 pm
From: "Larry Thong"


Savageduck wrote:

> You poor soul, you are solely without sole.

Like I always tell the Brotha! "If I had your shoes I'd have soul"


== 4 of 4 ==
Date: Wed, Apr 22 2009 4:37 pm
From: Chris Malcolm


In rec.photo.digital.slr-systems Frank ess <frank@fshe2fs.com> wrote:
> Chris Malcolm wrote:
>> In rec.photo.digital.slr-systems Bill Graham <weg9@comcast.net>
>> wrote:
>>
>>> "Frank ess" <frank@fshe2fs.com> wrote in message
>>> news:GL2dnfCROt7f0HDUnZ2dnUVZ_r-dnZ2d@giganews.com...
>>>>
>>>> STILL guess I need to have someone show me an example of a visual
>>>> pun that does not depend on words.
>>
>>> Isn't the definition of a pun a "play on words"? - If it is, then
>>> a pun that doesn't depend on words would be impossible.
>>
>> I think you're missing that important feature of human natural
>> language which allows the meanings of words to be extended. That's
>> why for example we can talk of cameras having a family resemblance
>> even though cameras don't have families, why we can talk of high
>> contrast even though it's no higher off the ground than low
>> contrast, and so on. And why we can talk of visual puns.

> WTF is "human natural language"? Language is not natural. It's an
> artefact of natural processes.

In linguistics and cognitive science "human natural language" is used
to describe those human languages which have been naturally developed
as opposed to those specifically invented languages such as Esperanto,
algebra, and Fortran.

--
Chris Malcolm


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

== 1 of 5 ==
Date: Wed, Apr 22 2009 12:40 pm
From: "Frank ess"


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.

--
Frank ess

== 2 of 5 ==
Date: Wed, Apr 22 2009 1:51 pm
From: John McWilliams


Paul Giverin wrote:
> In message <N6ednUn8YIsgyHPUnZ2dnUVZ8gidnZ2d@novis.pt>, Focus
> <dont@mail.me> writes
>> 70 MPG
>> http://caldasdarai << Snipped bits out >>
>> ;-)
> Do you really have to cross post this shite to all these groups?

He seems to have a need to x-post. Sometimes crap and sometimes not.

One thing folks can do is remove extraneous groups but the one they wish
to read:
[out]
uk.rec.photo.misc
rec.photo.digital.slr-systems
aus.photo

--
John McWilliams


== 3 of 5 ==
Date: Wed, Apr 22 2009 3:09 pm
From: Bruce


"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. ;-)

== 4 of 5 ==
Date: Wed, Apr 22 2009 4:07 pm
From: "Frank ess"


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?

== 5 of 5 ==
Date: Wed, Apr 22 2009 4:39 pm
From: Bruce


"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. ;-)


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

== 1 of 2 ==
Date: Wed, Apr 22 2009 3:17 pm
From: "Charles"

"Ken" <none@none.co.uk> wrote in message
news:49ef49a2$0$2544$da0feed9@news.zen.co.uk...
>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?

LCDs are terrible in outside bright light.


== 2 of 2 ==
Date: Wed, Apr 22 2009 3:28 pm
From: Alfred Molon


In article <49ef49a2$0$2544$da0feed9@news.zen.co.uk>, Ken says ...
> 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?

The LCD of the Sony R1 works fine even in the brightest daylight, even
with the midday sun shining on it. On the other hand the LCD of the Sony
A350 (a DSLR) performs quite poorly in bright light.
--

Alfred Molon
------------------------------
Olympus 50X0, 8080, E3X0, E4X0, E5X0 and E3 forum at
http://tech.groups.yahoo.com/group/MyOlympus/
http://myolympus.org/ photo sharing site

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

== 1 of 3 ==
Date: Wed, Apr 22 2009 3:25 pm
From: Alfred Molon


In article <49edbe48$0$90268$14726298@news.sunsite.dk>, Hans Kruse says
...
>
> "Alfred Molon" <alfred_molon@yahoo.com> wrote in message
> news:MPG.2457c9bd9eafea7a98bfb3@news.supernews.com...
> > In article <49ed7e81$0$90275$14726298@news.sunsite.dk>, Hans Kruse says
> > ...
> >
> >> This issue has been known for a long time. MLU is available for that
> >> reason.
> >
> > According to the article:
> >
> > "it was confirmed that the vibration generated by releasing the shutter
> > remains even when a picture is taken after a certain period of time from
> > the mirror lockup to prevent a mirror shock"
>
> The shutter release vibrations has nothing to do with getting rid of the
> mirror, does it?

They obviously mean the mirror induced vibrations.
--

Alfred Molon
------------------------------
Olympus 50X0, 8080, E3X0, E4X0, E5X0 and E3 forum at
http://tech.groups.yahoo.com/group/MyOlympus/
http://myolympus.org/ photo sharing site


== 2 of 3 ==
Date: Wed, Apr 22 2009 4:22 pm
From: Alan Browne


Alfred Molon wrote:
> In article <49edbe48$0$90268$14726298@news.sunsite.dk>, Hans Kruse says
> ...
>> "Alfred Molon" <alfred_molon@yahoo.com> wrote in message
>> news:MPG.2457c9bd9eafea7a98bfb3@news.supernews.com...
>>> In article <49ed7e81$0$90275$14726298@news.sunsite.dk>, Hans Kruse says
>>> ...
>>>
>>>> This issue has been known for a long time. MLU is available for that
>>>> reason.
>>> According to the article:
>>>
>>> "it was confirmed that the vibration generated by releasing the shutter
>>> remains even when a picture is taken after a certain period of time from
>>> the mirror lockup to prevent a mirror shock"
>> The shutter release vibrations has nothing to do with getting rid of the
>> mirror, does it?
>
> They obviously mean the mirror induced vibrations.

The shutter induces vibrations as well, esp. in focal plane SLR's. In
lens shuttered systems, it is greatly reduced as long as the mirror is
locked up first.


--
-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm
-- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm
-- [SI] gallery & rulz: http://www.pbase.com/shootin
-- e-meil: Remove FreeLunch.
-- usenet posts from gmail.com and googlemail.com are filtered out.


== 3 of 3 ==
Date: Wed, Apr 22 2009 4:31 pm
From: nospam


In article <bvOdnVtm1-hfO3LUnZ2dnUVZ_qmdnZ2d@giganews.com>, Alan Browne
<alan.browne@Freelunchvideotron.ca> wrote:

> > They obviously mean the mirror induced vibrations.
>
> The shutter induces vibrations as well, esp. in focal plane SLR's.

insignificant.

==============================================================================
TOPIC: Focus Confirmation
http://groups.google.com/group/rec.photo.digital/t/e4cdfb75a347ac36?hl=en
==============================================================================

== 1 of 4 ==
Date: Wed, Apr 22 2009 4:24 pm
From: Eugene


On Apr 23, 12:45 am, John Passaneau <jx...@psu.edu> wrote:
> Eugene wrote:
> > On Apr 22, 9:59 pm, John Passaneau <jx...@psu.edu> wrote:
> >> Eugene wrote:
> >>> Hi,
> >>> In Canon DSLR, there is a Focus Confirmation
> >>> dot in the viewfinder. Supposed you are using
> >>> Manual Focus. Does this Focus Confirmation
> >>> works by Phase-Difference Sensor with
> >>> AF lights or does it use Contrast Detection
> >>> like in those models with Live View Mode?
> >>> (or other mechanisms that doesn't use
> >>> the two?
> >>> E
> >> It uses the same sensor that is used for auto focus. The
> >> Phase-Difference  method is used in the live view mode because the
> >> mirror is up in live view and the auto focus sensor is blocked. In
> >> manual focus the mirror is down and the auto focus sensor is active.
>
> >> John Passaneau
>
> > But how could that be. In manual focus, no infrared light is
> > sent to the subject to gauge distance because it is
> > manual focus in the first place where you are the one
> > to adjust the distance. Also I'm talking about the focus
> > confirmation in other Canon without Live View like
> > the 20D, etc.
>
> > E
>
> That is because Canon DSLR's don't use infrared light to auto focus.
> It's auto focus sensors are passive. This is why in low light the auto
> focus becomes slow or doesn't work.
>
> John Passaneau- Hide quoted text -
>
> - Show quoted text -

Why come point&shoot digicam doesn't use phase detection
autofocusing. If it is costly. How come the DSLR doesn't
use the cheaper Active Autofocus used in point&shoot
which emits light and use reflections to gauge distance.
Both are equally fast and accurate.

E


== 2 of 4 ==
Date: Wed, Apr 22 2009 4:29 pm
From: nospam


In article
<765c2bff-e250-4b4f-bbe3-0de0c9bede41@d2g2000pra.googlegroups.com>,
Eugene <eugenhughes@gmail.com> wrote:

> Why come point&shoot digicam doesn't use phase detection
> autofocusing.

where would you put the phase detect sensors and mirror?

> If it is costly. How come the DSLR doesn't
> use the cheaper Active Autofocus used in point&shoot
> which emits light and use reflections to gauge distance.
> Both are equally fast and accurate.

cameras haven't used autofocus systems that emit light or sound for a
*long* time. they also don't work very well.


== 3 of 4 ==
Date: Wed, Apr 22 2009 4:36 pm
From: Eugene


On Apr 23, 7:29 am, nospam <nos...@nospam.invalid> wrote:
> In article
> <765c2bff-e250-4b4f-bbe3-0de0c9bed...@d2g2000pra.googlegroups.com>,
>
> Eugene <eugenhug...@gmail.com> wrote:
> > Why come point&shoot digicam doesn't use phase detection
> > autofocusing.
>
> where would you put the phase detect sensors and mirror?

Beside the CCD.

>
> > If it is costly. How come the DSLR doesn't
> > use the cheaper Active Autofocus used in point&shoot
> > which emits light and use reflections to gauge distance.
> > Both are equally fast and accurate.
>
> cameras haven't used autofocus systems that emit light or sound for a
> *long* time.  they also don't work very well.

I had Sony point&shoot digicam before like T1 and others where
it can send red light beam to the subject. If it doesn't detect
focus by calculating the reflections. What method then
does it use to autofocus? Maybe the red light is just to
make better the contrast and so contrast autofocus
can work??

In Canon DSLR, why doesn't it emit red light too but
the flash itself for Phase Detection Autofocus. If
flash is brighter, why doesn't point and shoot digicam
uses flash to highlight contrast for autofocus?

E

== 4 of 4 ==
Date: Wed, Apr 22 2009 4:51 pm
From: nospam


In article
<dd49428f-f9c6-45cb-8e52-34b7b18b73b9@r31g2000prh.googlegroups.com>,
Eugene <eugenhughes@gmail.com> wrote:

> I had Sony point&shoot digicam before like T1 and others where
> it can send red light beam to the subject. If it doesn't detect
> focus by calculating the reflections. What method then
> does it use to autofocus? Maybe the red light is just to
> make better the contrast and so contrast autofocus
> can work??

that's a focus assist light so that the actual autofocus system can
find something on which to focus.

> In Canon DSLR, why doesn't it emit red light too but
> the flash itself for Phase Detection Autofocus. If
> flash is brighter, why doesn't point and shoot digicam
> uses flash to highlight contrast for autofocus?

some cameras use flash for autotfocus assist and others use infrared
(and sometimes just red) light. i find the ones that use repeating
flash to be annoying as hell.

==============================================================================
TOPIC: Great forum!
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== 1 of 1 ==
Date: Wed, Apr 22 2009 4:58 pm
From: "Focus"

http://atlantic-diesel.com

International forum with very much possibilities.

Check it out. Free and no advertisements.


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