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From: Chris Malcolm on 23 Apr 2010 04:50
In rec.photo.digital John McWilliams <jpmcw(a)comcast.net> wrote:
> Mxsmanic wrote:
>> RichA writes:
>>
>>> Canon. Will they release a compact non-mirrored, interchangeable lens
>>> camera?
>>> Nikon. Will they release a compact non-mirrored camera and/or an ,
>>> high megapixel FF camera that doesn't cost $8000?
>>
>> What kind of SLR doesn't have a mirror?

> Self limiting: 0! Unless they make something besides a mirror that reflexes.

How about electronic reflex? Take the signal from the sensor, process
it, and "reflex" it up to the EVF display by means of wires?

--
Chris Malcolm
From: Pete on 23 Apr 2010 04:54
On 2010-04-23 01:11:14 +0100, Chris Malcolm said:

> In rec.photo.digital Pete <available.on.request(a)aserver.invalid> wrote:
>> <>
>> Yes, and until sensors plus software can exceed the night-adaptive
>> vision of the human eye, framing of very low light shots will remain a
>> difficulty without an optical finder.
>
> That point has been reached. In the very dimmest conditions I have to
> use the LCD of my DSLR because I can see more than I can through the
> optical viewfinder or with the naked eye. This was demonstrated very
> clearly recently when I tried to take available light shots in a dark
> tunnel. At ISO 200 and f8 the shutter speed required was more than 30
> minutes.

That is very useful, of course. My situation is entirely different:
there is enough light to see the view in my optical finder. Use of the
LCD reduces my night vision because it is brighter than the scene, the
colours are different, and the image is noisy. My preference is for
optical finders just as I prefer writing with a pen than a pencil, if
pencils could be made to have the same characteristics as a pen I would
no longer have a preference.

--
Pete

From: Martin Brown on 23 Apr 2010 05:53
Chris Malcolm wrote:
> In rec.photo.digital Pete <available.on.request(a)aserver.invalid> wrote:
>> On 2010-04-22 18:48:08 +0100, C J Campbell said:
>
>>> On 2010-04-22 01:00:32 -0700, "Ray Shafranski" <me(a)privacy.net> said:
>>>
>>>> <>
>>>> The lifting mirror and the pentaprism/pentamirror are relics of film days
>>>> and should be replaced on all DSLR designs.
>>> Not so much a relic of film but of the need for clear, bright, optical
>>> viewfinders. You are not going to get as good a picture holding the
>>> camera out in front of you (as you must do with the Olympus E-PL1, for
>>> example) as you will with the camera braced by your face. Mirrorless is
>>> great for the photography masses who really don't care about picture
>>> quality, but it has a ways to go before it is usable by pros. So, I
>>> would say the lifting mirror and pentaprism will disappear on consumer
>>> DSLRs soon, but it is going to be on pro cameras for awhile yet.
>
>> Yes, and until sensors plus software can exceed the night-adaptive
>> vision of the human eye, framing of very low light shots will remain a
>> difficulty without an optical finder.
>
> That point has been reached. In the very dimmest conditions I have to
> use the LCD of my DSLR because I can see more than I can through the
> optical viewfinder or with the naked eye. This was demonstrated very
> clearly recently when I tried to take available light shots in a dark
> tunnel. At ISO 200 and f8 the shutter speed required was more than 30
> minutes.

Something wrong with your numbers there. If it was that dark then the 1s
time averaged viewfinder image would still be 11 stops underexposed
which would be indistinguishable from black cat in a coal cellar. Dazzle
from the LCD can be a nuisance in low light conditions too.

Which SLR can meter for a 30 min exposure at 200 ASA? I'd be surprised
if on that timescale the image wasn't dominated by stray IR photons in
the sensor and warm spots from the control electronics.

Astronomical cameras can now focus better than humans by repeatedly
sampling highlights in the image, but generic DSLR autofocus tends to
hunt in low light conditions and manual focus is more reliable. YMMV

Regards,
Martin Brown
From: Bruce on 23 Apr 2010 06:35
On Thu, 22 Apr 2010 18:58:46 -0700 (PDT), Rich <rander3127(a)gmail.com>
wrote:
>On Apr 22, 7:41�am, Bruce <docnews2...(a)gmail.com> wrote:
>> On Wed, 21 Apr 2010 20:39:37 -0700 (PDT), RichA <rander3...(a)gmail.com>
>> wrote:
>
>> Kodak and Pentax are talking right now. �Watch this space.
>
>I don't know where that will go. Kodak makes medium format CCDs that
>make FF CMOS look like what they are, well noise-controlled but
>ultimately crude consumer devices. However, going back to Kodak CCDs
>for small sensors will be a problem since noise is the be-all, end-all
>of sensor performance these days.


Kodak makes full frame (35mm-size) CMOS and CCDs.

From: Pete on 23 Apr 2010 07:26
On 2010-04-23 10:53:23 +0100, Martin Brown said:

> Chris Malcolm wrote:
>> In rec.photo.digital Pete <available.on.request(a)aserver.invalid> wrote:
>>> On 2010-04-22 18:48:08 +0100, C J Campbell said:
>>
>>>> On 2010-04-22 01:00:32 -0700, "Ray Shafranski" <me(a)privacy.net> said:
>>>>
>>>>> <>
>>>>> The lifting mirror and the pentaprism/pentamirror are relics of film days
>>>>> and should be replaced on all DSLR designs.
>>>> Not so much a relic of film but of the need for clear, bright, optical
>>>> viewfinders. You are not going to get as good a picture holding the
>>>> camera out in front of you (as you must do with the Olympus E-PL1, for
>>>> example) as you will with the camera braced by your face. Mirrorless is
>>>> great for the photography masses who really don't care about picture
>>>> quality, but it has a ways to go before it is usable by pros. So, I
>>>> would say the lifting mirror and pentaprism will disappear on consumer
>>>> DSLRs soon, but it is going to be on pro cameras for awhile yet.
>>
>>> Yes, and until sensors plus software can exceed the night-adaptive
>>> vision of the human eye, framing of very low light shots will remain a
>>> difficulty without an optical finder.
>>
>> That point has been reached. In the very dimmest conditions I have to
>> use the LCD of my DSLR because I can see more than I can through the
>> optical viewfinder or with the naked eye. This was demonstrated very
>> clearly recently when I tried to take available light shots in a dark
>> tunnel. At ISO 200 and f8 the shutter speed required was more than 30
>> minutes.
>
> Something wrong with your numbers there. If it was that dark then the
> 1s time averaged viewfinder image would still be 11 stops underexposed
> which would be indistinguishable from black cat in a coal cellar.
> Dazzle from the LCD can be a nuisance in low light conditions too.

Agreed and dazzle screws up my night vision making the LCD useless.

> Which SLR can meter for a 30 min exposure at 200 ASA? I'd be surprised
> if on that timescale the image wasn't dominated by stray IR photons in
> the sensor and warm spots from the control electronics.

If there is a hand-held meter that can get anywhere near this
sensitivity, let me know - I've been trying to find a meter for
low-light.

--
Pete

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