Sony's Alpha 700 replacement to be mirrorless SLT, with APS-C sensor

"RichA" wrote in message
...
On Sep 21, 5:59 pm, Bruce wrote:
Oh dear. 'Pellicle mirror disease' is spreading through the Alpha
range, with several reports of a mock-up of an A700 replacement on the
Sony stand at Photokina.

So stand by for the A77 to be released in January. Given that the
Alpha 850 and 900 are both discontinued, will the A77 become the new
top model of the Sony Alpha range?http://preview.tinyurl.com/32mwlkq
or:http://www.amateurphotographer.co.uk...0_replacement_...

Do you believe in ghosts? You'd better, if you buy one of these.
;-)http://preview.tinyurl.com/3873ep2
or:http://forums.dpreview.com/forums/re...ssage=36125668

That is going to disappoint a lot of A700 fans. Sacrificing light
throughput, contrast and probably sharpness in order to get faster
frames per second.

And reliability, robustness etc. etc.

It also probably means that when you open the camera the sensor is not
exposed (e.g. to dust) and assuming the mirroring is on the inside face the
pellicle easy to clean.

"RichA" wrote in message
...
On Sep 22, 8:32 am, "R. Mark Clayton"
wrote:
"RichA" wrote in message

...
On Sep 21, 5:59 pm, Bruce wrote:

Oh dear. 'Pellicle mirror disease' is spreading through the Alpha
range, with several reports of a mock-up of an A700 replacement on the
Sony stand at Photokina.

So stand by for the A77 to be released in January. Given that the
Alpha 850 and 900 are both discontinued, will the A77 become the new
top model of the Sony Alpha range?http://preview.tinyurl.com/32mwlkq
or:http://www.amateurphotographer.co.uk...0_replacement_...

Do you believe in ghosts? You'd better, if you buy one of these.
;-)http://preview.tinyurl.com/3873ep2
or:http://forums.dpreview.com/forums/re...ssage=36125668

That is going to disappoint a lot of A700 fans. Sacrificing light
throughput, contrast and probably sharpness in order to get faster
frames per second.

And reliability, robustness etc. etc.

It also probably means that when you open the camera the sensor is not
exposed (e.g. to dust) and assuming the mirroring is on the inside face
the
pellicle easy to clean.

The mirror will likely have a dichroic coating, could be fragile.
Additionally, it very well may be on the inside surface, to protect it
from being scratched and that could be what is causing the image
doubling issues. Even a thin piece of glass, plane-parallel can cause
a double image. This is why telescope mirrors and any mirrors used in
optics are "first surface" because making them second-surface produces
internal reflections.

Well indeed, but only on the viewfinder NOT on the sensor.

On Thu, 23 Sep 2010 19:18:09 +0100, "R. Mark Clayton"
wrote:


"RichA" wrote in message
...
On Sep 22, 8:32 am, "R. Mark Clayton"
wrote:
"RichA" wrote in message

...
On Sep 21, 5:59 pm, Bruce wrote:

Oh dear. 'Pellicle mirror disease' is spreading through the Alpha
range, with several reports of a mock-up of an A700 replacement on the
Sony stand at Photokina.

So stand by for the A77 to be released in January. Given that the
Alpha 850 and 900 are both discontinued, will the A77 become the new
top model of the Sony Alpha range?http://preview.tinyurl.com/32mwlkq
or:http://www.amateurphotographer.co.uk...0_replacement_...

Do you believe in ghosts? You'd better, if you buy one of these.
;-)http://preview.tinyurl.com/3873ep2
or:http://forums.dpreview.com/forums/re...ssage=36125668

That is going to disappoint a lot of A700 fans. Sacrificing light
throughput, contrast and probably sharpness in order to get faster
frames per second.

And reliability, robustness etc. etc.

It also probably means that when you open the camera the sensor is not
exposed (e.g. to dust) and assuming the mirroring is on the inside face
the
pellicle easy to clean.

The mirror will likely have a dichroic coating, could be fragile.
Additionally, it very well may be on the inside surface, to protect it
from being scratched and that could be what is causing the image
doubling issues. Even a thin piece of glass, plane-parallel can cause
a double image. This is why telescope mirrors and any mirrors used in
optics are "first surface" because making them second-surface produces
internal reflections.

Well indeed, but only on the viewfinder NOT on the sensor.


You people seriously need to educate yourselves on what is meant by a
"pellicle mirror". Being often only a few molecules thick. Apparently, if
internal reflections are causing this image degradation, then the word
"pellicle" is being widely misused and the usual resident TROLLS are just
parroting what they know not.

SNIP


Well indeed, but only on the viewfinder NOT on the sensor.


You people seriously need to educate yourselves on what is meant by a
"pellicle mirror". Being often only a few molecules thick. Apparently, if
internal reflections are causing this image degradation, then the word
"pellicle" is being widely misused and the usual resident TROLLS are just
parroting what they know not.

Well I haven't taken an a700 apart, but what I would expect to see is a
thin, but robust, piece of glass at 45 degrees with a very partial mirror (a
sputtering of metal "a few molecules thick") on the rear side. There might
be some reflection off the front face, but as this is going to the view
finder NOT the sensor the worst that will happen is slight ghosting in the
eyepiece. The final image will be virtually unaffected apart from the light
lost to the viewfinder and perhaps a very faint secondary reflection.

On Mon, 27 Sep 2010 17:48:02 +0100, "R. Mark Clayton"
wrote:

Well I haven't taken an a700 apart, but what I would expect to see is a
thin, but robust, piece of glass

Then you don't know what a pellicle mirror is.

In article , Russ D
wrote:

On Mon, 27 Sep 2010 17:48:02 +0100, "R. Mark Clayton"
wrote:

Well I haven't taken an a700 apart, but what I would expect to see is a
thin, but robust, piece of glass

Then you don't know what a pellicle mirror is.

A wonderful bird is the pellicle
Its reflection shows more than its graticule

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On 10-09-22 8:32 , R. Mark Clayton wrote:

That is going to disappoint a lot of A700 fans. Sacrificing light
throughput, contrast and probably sharpness in order to get faster
frames per second.

Losing 33% of light is easily compensated with a 1/2 stop increase in
ISO setting. In the a700 replacement, the mirror can be flipped out of
the way, as well (from what I've read). If you use fast lenses, it's
probably not an issue in the first place.

While I have my misgivings about Sony's direction (and esp. the ghost
issue), I also look at the positives:

-ability to review images in the EVF - no ambient light issues.
-phase detect focus (faster than contrast and allows AF during video (if
that's your thing).

-Possibly no "interrupt" shooting. Eg: no "blackout" during the shutter
cycle (I don't know if that's the case) or at least a very short blackout.

Possibly the ghosting issue can be solved (wishful/hopeful thinking
perhaps).

What worries me more is what they may do with the a900 successor. Some
sites claim that Sony are not looking back, that the pelicle and EVF's
are the sole path forward. 2B seen.

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