DSLR

On Thu, 04 Dec 2008 12:23:46 -0800, SMS wrote:

Andrew Koenig wrote:
"measekite" wrote in message
...

Notwithstanding the new Pan 4/3 maybe the future for the DSLR would be the
DEVF. That would be a new camera where the Electronic View Finder
replaces the optical viewfinder and all else stays the same including the
sensor and the lenses. It would seem that you now have the same image
quality, a very high quality EVF and continuous Live View.

The trouble with electronic viewfinders is that the image on them lags a
fraction of a second behind reality, especially in low light. Often that
doesn't matter; but when it does, it really does.

Yes, it's very disconcerting because the lag isn't constant, it varies
by the light level. Don't look for optical viewfinders on D-SLRs to
disappear any time soon.


So speaks someone who's never had the pleasure of using a live-view EVF to any
extent, other than playing with them in the local store (if even that). That
"lag" is the shutter speed being correctly relayed to the viewfinder. With this
you can dial-in the exact shutter speed that you need to blur moving water or
stop the motion of a bird's wings and see how that shutter speed will precisely
effect the photograph, before you even press the shutter. Think of
depth-of-field preview, but now you don't just get aperture-effects preview, you
also get shutter-speed-effects preview.

Please, idiots, go educate yourselves, get some real experience with real
cameras. Your pretend-photographer net-life troll status is glaringly obvious.

"leon_preston" wrote in message
...

So speaks someone who's never had the pleasure of using a live-view EVF to
any
extent, other than playing with them in the local store (if even that).
That
"lag" is the shutter speed being correctly relayed to the viewfinder.

Not on the cameras I've used, it isn't. It's much longer than the shutter
speed.

Jürgen Exner wrote:
Don Stauffer wrote:
The main differentiation is, does the viewfinder look optically through
the main lens, or does the viewfinder use an electronic viewscreen. If
your eye is actually viewing the scene through the objective lens it is
a single lens reflex.

Unless somewhere there is a mirror involved it is not a reflex.

jue

There may be a beamsplitter prism used instead.
The Olympus E-10 and E-20 are examples: even thought they both have
non-interchangeable lens, they have an optical TTL* viewfinder just like
any other SLR camera.
The beamsplitter allows both the viewfinder and live-view LCD to
function at the same time.
It's almost a shame that the design hasn't been scaled up to an APS-c or
24x36mm sensor size and been given a mount for an interchangeable lens.




*TTL = Through The Lens.

dj_nme wrote:
Jürgen Exner wrote:
Don Stauffer wrote:
The main differentiation is, does the viewfinder look optically
through the main lens, or does the viewfinder use an electronic
viewscreen. If your eye is actually viewing the scene through the
objective lens it is a single lens reflex.

Unless somewhere there is a mirror involved it is not a reflex.

jue

There may be a beamsplitter prism used instead.
The Olympus E-10 and E-20 are examples: even thought they both have
non-interchangeable lens, they have an optical TTL* viewfinder just like
any other SLR camera.
The beamsplitter allows both the viewfinder and live-view LCD to
function at the same time.
It's almost a shame that the design hasn't been scaled up to an APS-c or
24x36mm sensor size and been given a mount for an interchangeable lens.

It's a shame that Canon have not revived the pellicle of the EOS-1N RS
where the mirror was semi-silvered and did not move.

Cuts the shutter delay from 50ms to about 5ms.

And with today's low noise, high ISO cameras, this would be esp. welcome.


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Alan Browne wrote:
dj_nme wrote:
Jürgen Exner wrote:
Don Stauffer wrote:
The main differentiation is, does the viewfinder look optically
through the main lens, or does the viewfinder use an electronic
viewscreen. If your eye is actually viewing the scene through the
objective lens it is a single lens reflex.

Unless somewhere there is a mirror involved it is not a reflex.

jue

There may be a beamsplitter prism used instead.
The Olympus E-10 and E-20 are examples: even thought they both have
non-interchangeable lens, they have an optical TTL* viewfinder just
like any other SLR camera.
The beamsplitter allows both the viewfinder and live-view LCD to
function at the same time.
It's almost a shame that the design hasn't been scaled up to an APS-c
or 24x36mm sensor size and been given a mount for an interchangeable
lens.

It's a shame that Canon have not revived the pellicle of the EOS-1N RS
where the mirror was semi-silvered and did not move.

Cuts the shutter delay from 50ms to about 5ms.

And with today's low noise, high ISO cameras, this would be esp. welcome.

Maybe there is some problem with scaling-up the Oly ZLR camera design
which I can't foresee and that Canon technical people feel that a
pellicle mirror is too fragile?
I don't know, but some obsolete designs seem to have some good concepts
which I believe should be revisited.

In article
, dj_nme
wrote:

It's a shame that Canon have not revived the pellicle of the EOS-1N RS
where the mirror was semi-silvered and did not move.

Cuts the shutter delay from 50ms to about 5ms.

And with today's low noise, high ISO cameras, this would be esp. welcome.

Maybe there is some problem with scaling-up the Oly ZLR camera design
which I can't foresee and that Canon technical people feel that a
pellicle mirror is too fragile?
I don't know, but some obsolete designs seem to have some good concepts
which I believe should be revisited.

http://forums.dpreview.com/forums/read.asp?forum=1021&message=29972442

issues include dust, light leaking in via the viewfinder, light loss
thru the mirror and still needing a secondary mirror for the autofocus
sensors.

dj_nme wrote:

which I can't foresee and that Canon technical people feel that a
pellicle mirror is too fragile?

There is nothing especial 'different' other than it is a semi-silvered
mirror. Fragility is not the issue. (esp. as it doesn't move at all).


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nospam wrote:
In article
, dj_nme
wrote:

It's a shame that Canon have not revived the pellicle of the EOS-1N RS
where the mirror was semi-silvered and did not move.

Cuts the shutter delay from 50ms to about 5ms.

And with today's low noise, high ISO cameras, this would be esp. welcome.
Maybe there is some problem with scaling-up the Oly ZLR camera design
which I can't foresee and that Canon technical people feel that a
pellicle mirror is too fragile?
I don't know, but some obsolete designs seem to have some good concepts
which I believe should be revisited.

http://forums.dpreview.com/forums/read.asp?forum=1021&message=29972442

issues include dust,

Au contraire.

A pellicle mirror would keep dust off of the sensor and much further OOF
even stopped down. Dust cleaning would be easier and lower risk for
scratching.

light leaking in via the viewfinder,

1) a) The advantage of the pellicle is keeping your eye glued to the VF
during action. This blocks a lot of light. b) One could also add soft
eyesocket VF shades.

2) The pellicle would be directing leak light away from the sensor or
passing it to the bottom of the mirror box (which could also be baffled
to prevent further scattering).

3) (Kludge): A shutter (driven by the film plane shutter) could also be
added to the VF. I doubt this is needed, esp. if 1 b) above is added.

light loss

With fast lenses this is not much of an issue for the photographers view
and with low noise/high ISO sensors, even less so for the image.

thru the mirror and still needing a secondary mirror for the autofocus
sensors.

Was not a problem with the EOS-1n RS.

I'm not sure how they did the AF, perhaps in the prism assembly?

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In article ,
Andrew Koenig says...

Not on the cameras I've used, it isn't. It's much longer than the shutter
speed.

That feature is not available on all cameras. Only some P&S offer motion
blur preview, such as the Sony R1 for instance.
--

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

Alan Browne wrote:
dj_nme wrote:

which I can't foresee and that Canon technical people feel that a
pellicle mirror is too fragile?

There is nothing especial 'different' other than it is a semi-silvered
mirror. Fragility is not the issue. (esp. as it doesn't move at all).

Are you sure?
From what I remember from handling an old Pellix is that the mirror
itself doesn't appear to be very sturdy.
It could easily be scratched, then you get blurring and darkening in
both the viewfinder and photographs.
I am prepared to be wrong, but I'm pretty sure there's a good reason why
the design hasn't resurfaced recently.