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Archive 2013 · Official: Sony A7 and A7R Fullframe Mirrorless
  
 
carstenw
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p.149 #1 · p.149 #1 · Official: Sony A7 and A7R Fullframe Mirrorless


carstenw wrote:
They also forgot the adapter. There is a spot in the lens setup for the adapter, but there are no choices in it.


This is what it should look like. Excuse the rush job.








Dec 29, 2013 at 12:57 AM
jhenderson0107
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p.149 #2 · p.149 #2 · Official: Sony A7 and A7R Fullframe Mirrorless


Toothwalker wrote:
Unclear. 11 bits cannot support the purported dynamic range of 14 EV.

Edit: A bit depth of 11 bits does no justice to a dynamic range of 14 EV. Or is it a matter of definition - again? If the dynamic range (the ratio of the largest non-saturating input signal to the smallest detectable input signal) is 14 EV, I would use at least 14 bits to store the information.

All analog to digital converters are imperfect. The ENOB (effective number of bits) of state-of-the-art 14-bit converters sampling at ~180 MHz (as within in the A7R ) is very close to 11 bits, so there is little justification to encode more that 11-bits into the compressed RAW image. The use of 11-bit samples within the signal processing chain in conjunction with the delta-encoding is well proportioned and fully justifiable, and is almost certainly visually-lossless in all but extreme corner cases.



Dec 29, 2013 at 01:54 AM
akuba
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p.149 #3 · p.149 #3 · Official: Sony A7 and A7R Fullframe Mirrorless


Taylor Sherman wrote:
I wonder if they didn't have the processing power to do a more traditional, lossless compression on the RAW files. The space savings going from 14bpp to 8bpp is fairly substantial, but of course with a lossless compression, many images would have only been about 50% of the max possible size anyway.


Regarding processing power: Venturing into speculation land, I suspect the driving constraint for Sony was either buffer space or data throughput. The algorithm they are using has the properties that it can be pipelined (it doesn't need all of the data to be staged in a buffer but can be applied as the data is streamed) and it produces compressed data with a fixed upper bound on its size (that being the 36M bytes). While many lossless algorithms can be pipelined, none of them can guarantee a fixed-sized upper bound on the output. In fact most can result in the compressed data being larger than the uncompressed data for worst-case inputs. Most implementations fall back to storing the uncompressed data in those cases but that requires either buffering all of the input data or reprocessing the bloated output back into the raw input for final storage. But at this point I'm digressing too far into computer science geekery so I'll leave it at that. I would assume Sony did a bunch of benchmarking with a representative set of images and concluded this algorithm met their design constraints whereas lossless ones did not.

jhenderson0107 wrote:
All analog to digital converters are imperfect. The ENOB (effective number of bits) of state-of-the-art 14-bit converters sampling at ~180 MHz (as within in the A7R ) is very close to 11 bits, so there is little justification to encode more that 11-bits into the compressed RAW image. The use of 11-bit samples within the signal processing chain in conjunction with the delta-encoding is well proportioned and fully justifiable, and is almost certainly visually-lossless in all but extreme corner cases.


The ENOB may be around 11.5 or so, so there may be some signal being lost as well, but I agree that the algorithm should be visually lossless for well-exposed images and that for everything but the deep shadows we're probably losing mostly noise. If I'm not mistaken, I recall mention that Sony may also be cooking deconvolution sharpening into the RAW, so the definition of what is raw may be changing anyway. But for peace of mind and for being able to push exposure in post-processing I personally would still prefer losslessy compressed data. Storage is cheap while paranoia is taxing. I think at this point most of us are fairly convinced that the encoding is good enough, but I'm not sure many of us would choose this encoding if there were a lossless option in the menu.



Dec 29, 2013 at 04:55 AM
zhangyue
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p.149 #4 · p.149 #4 · Official: Sony A7 and A7R Fullframe Mirrorless




jhenderson0107 wrote:
All analog to digital converters are imperfect. The ENOB (effective number of bits) of state-of-the-art 14-bit converters sampling at ~180 MHz (as within in the A7R ) is very close to 11 bits, so there is little justification to encode more that 11-bits into the compressed RAW image. The use of 11-bit samples within the signal processing chain in conjunction with the delta-encoding is well proportioned and fully justifiable, and is almost certainly visually-lossless in all but extreme corner cases.


throw away data and effective NOB is very different to me. I don't know where this effect of bit data come from, but sounds very low to me.
this truncated effect will not easily showing regular capture or jpeg from camera but doing post process, the finer step of bit/information get truncated so you don't have the same freedom to do local burn or dodge to remap the bit.
I don't know you guys but I can see this effect in LR editing more often with A7/A7r. Exact the 'thin' file comment I fully agree. I haven't try any other raw converters other than LR though.



Dec 29, 2013 at 07:19 AM
zhangyue
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p.149 #5 · p.149 #5 · Official: Sony A7 and A7R Fullframe Mirrorless



akuba wrote:
Regarding processing power: Venturing into speculation land, I suspect the driving constraint for Sony was either buffer space or data throughput. The algorithm they are using has the properties that it can be pipelined (it doesn't need all of the data to be staged in a buffer but can be applied as the data is streamed) and it produces compressed data with a fixed upper bound on its size (that being the 36M bytes). While many lossless algorithms can be pipelined, none of them can guarantee a fixed-sized upper bound on the output. In fact most can result in the
...Show more
the truncate not only affect deep shadow but everywhere in the spectrums. The finer step is gone in everywhere along with PP/remap freedom.
I guess they have to leave out something for VII or A9.



Dec 29, 2013 at 07:24 AM
Toothwalker
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p.149 #6 · p.149 #6 · Official: Sony A7 and A7R Fullframe Mirrorless


akuba wrote:
The ENOB may be around 11.5 or so, so there may be some signal being lost as well, but I agree that the algorithm should be visually lossless for well-exposed images and that for everything but the deep shadows we're probably losing mostly noise. If I'm not mistaken, I recall mention that Sony may also be cooking deconvolution sharpening into the RAW, so the definition of what is raw may be changing anyway. But for peace of mind and for being able to push exposure in post-processing I personally would still prefer losslessy compressed data. Storage is cheap while paranoia
...Show more

Are they cooking deconvolution sharpening into the <del>RAW</del> upgraded JPEG? Yuk.

If it is true, one can expect artificial sharpness differences between native lenses and lenses whose f-number is not known to the camera.

Deconvolution sharpening is non-trivial, and if you want to do it properly you need information unavailable to the camera. I find it hard to believe that Sony would cook such an operation into their 'RAW' files.



Dec 29, 2013 at 10:24 AM
mahlemiut
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p.149 #7 · p.149 #7 · Official: Sony A7 and A7R Fullframe Mirrorless


Even if someone calls me a drama queen, I bought the A7r and really like the handling and what the sensor can give out at good conditions, but the flares/reflections I have detected with almost all of my lenses with more than 50 mm focal length is a killer criteria for me. Few examples:

Leica 2,8 60 Makro Elmarit (built in lens hood):





Leica 2,8 135 Elmarit (built in lens hood):


(sorry, that it is overexposed and focus is not set correct I just wanted to capture the effect and has been bored after realizing it)

Zeiss 1,7 50 Planar (Contax MM), lens hood attached, moving away from the light source:







Its way better using a wide angle lens (tested the 2,8 28 Distagon, Asahi super Takumar 3,5 35 and a PA Curtagon 4 35), I have been able to see it but much better than as with the other lenses.

It seems, that it is getting more worse using long focal length lenses and way better with short ones. I haven't had a chance to test a native lens, maybe it works much better.

I also did it using a Kippon Adapter (as for the pictures shown), a tilt adapter for EF Lenses and a Siocore automatic Adapter. Last one haven't had the issues but it already crops down to APS-C size as it does not have proper dimensions for Full Frame.

The effect does not only occur with point light sources, more light from one side is enough (for example reflection from white wall or mixed light in forests). Might be better with native lenses, but I would exclude the adapters, I manipulated one, using black velvet to prevent reflections caused by the adapter, and it does not help.

I have been able to prevent it by using something to shadowing the lenses in addition to the lens hoods, but the hoods has not been enough.

For all the lenses, I have been able to see this effect, I had no issues at all at the NEX-7, even without using lens hoods.

Call me a drama queen, but for me it is a no go criteria, as I often use long lenses, but the A7r may be a really great cam for people, which are almost using short lenses for landscapes.

It's sad, the sensor can really give great results, but for me, it's to hard to handle. Unfortunately I am over the returning back time and have to try to place over technical service.



Dec 29, 2013 at 04:53 PM
Toothwalker
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p.149 #8 · p.149 #8 · Official: Sony A7 and A7R Fullframe Mirrorless


mahlemiut wrote:
Call me a drama queen, but for me it is a no go criteria, as I often use long lenses, but the A7r may be a really great cam for people, which are almost using short lenses for landscapes.


You are not a drama queen. This is clearly unacceptable.

From the looks of it, reflections off the sensor itself are not involved. Do you also get this type of flare with highlights that are completely within the frame, or only when they are (completely or partly) outside the field of view?




Dec 29, 2013 at 05:18 PM
Makten
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p.149 #9 · p.149 #9 · Official: Sony A7 and A7R Fullframe Mirrorless


Light leaks? I had a Nikon to NEX adapter that had a big hole where the release button for the lens was. Immediately cured it, so I don't know if it would do any harm though.


Dec 29, 2013 at 05:26 PM
zhangyue
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p.149 #10 · p.149 #10 · Official: Sony A7 and A7R Fullframe Mirrorless



+1 about leak at adaptor. Easy test: close lens cap, do a exposure, you should see white border.
Makten wrote:
Light leaks? I had a Nikon to NEX adapter that had a big hole where the release button for the lens was. Immediately cured it, so I don't know if it would do any harm though.




Dec 29, 2013 at 05:35 PM
 

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mahlemiut
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p.149 #11 · p.149 #11 · Official: Sony A7 and A7R Fullframe Mirrorless


The cases I have seen, it might start if I turn away from a light source but more if I had stronger light from a side. First time I have realized it at a landscape shot. Sun has already went down the tree right behind me, only lighter area right of the camera. Also have seen it standing close to a open white door. Happens with all of my lenses i have tested and with the two adapter, which covers the full frame area. Only the cropping adapter had no issues.

Will check the adapters again regarding light leaks, but I never had issues on the nex-7, using the same. I have been able to prevent it by using something in addition to prevent direct light in direction of the lenses. Strange thing is, it is getting more worse using longer lenses :/



Dec 29, 2013 at 05:40 PM
mahlemiut
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p.149 #12 · p.149 #12 · Official: Sony A7 and A7R Fullframe Mirrorless


I just tested it. Mounted the kippon adapter and closed it using a fitting ef cap of the EOS50D-nothing to see, even using a strong LED lighter moving around the adapter. Seems not to be a light leak. I also tested 2 native EF lenses on the EF-E Mount adapter to crosscheck, if it might be a leak of one of the in-between adapters (eg. Contax-EF). Using the Bigma 50-500, it is fine at 50mm (I remember someone also tested the lens), but from 100mm onwards I can see these 'flares', pointing to a lightsource and turning away (sequenz of the last 3 captures).


Dec 29, 2013 at 06:08 PM
secondclaw
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p.149 #13 · p.149 #13 · Official: Sony A7 and A7R Fullframe Mirrorless


mahlemiut wrote:
I just tested it. Mounted the kippon adapter and closed it using a fitting ef cap of the EOS50D-nothing to see, even using a strong LED lighter moving around the adapter. Seems not to be a light leak. I also tested 2 native EF lenses on the EF-E Mount adapter to crosscheck, if it might be a leak of one of the in-between adapters (eg. Contax-EF). Using the Bigma 50-500, it is fine at 50mm (I remember someone also tested the lens), but from 100mm onwards I can see these 'flares', pointing to a lightsource and turning away (sequenz of
...Show more

Yea I was the one that tested Bigma, and was unable to replicate it at 50, but at 500 it was all ghostly. There are many types of flares, but its not yet settled whether the ugly flare we're experiencing is related to adapter or not. Clearly certain flares happen with native mount as well, but not these.

There is clearly interaction between non-native lens, adapter with a somewhat shiny light path (Metabones better fix it!), and mirrored sensor topping. It also must be happening outside the APS-C boundary, as using same lens/adapter on NEX-7 doesn't produce the effect.



Dec 29, 2013 at 06:30 PM
mahlemiut
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p.149 #14 · p.149 #14 · Official: Sony A7 and A7R Fullframe Mirrorless


Also tested it after lining the adapter with black velvet, same issue, no change. From my point of view, it seems to be a kind of reflecting issue using third party lenses with longer focal length on the A7r Sensor. Or a very bad copy of the A7r, but I would go for thirdparty/Sensor combination. As it does not happen in the extreme way using short focal length lenses, it might be, that it will not be recocnized from so many people.


Dec 29, 2013 at 06:58 PM
sebboh
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p.149 #15 · p.149 #15 · Official: Sony A7 and A7R Fullframe Mirrorless


could it be reflections off the mount flange?


Dec 29, 2013 at 07:09 PM
mahlemiut
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p.149 #16 · p.149 #16 · Official: Sony A7 and A7R Fullframe Mirrorless


maybe, but would be hard to fix for all the lenses :/ did not try, if it happens after painting the mount black for one of the lenses and would have to do it for all longer lenses, if it would help



Dec 29, 2013 at 07:14 PM
akuba
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p.149 #17 · p.149 #17 · Official: Sony A7 and A7R Fullframe Mirrorless


Toothwalker wrote:
Are they cooking deconvolution sharpening into the <del>RAW</del> upgraded JPEG? Yuk.

If it is true, one can expect artificial sharpness differences between native lenses and lenses whose f-number is not known to the camera.

Deconvolution sharpening is non-trivial, and if you want to do it properly you need information unavailable to the camera. I find it hard to believe that Sony would cook such an operation into their 'RAW' files.


One of the marquee features of the BIONZ X processor is "diffraction-reducing technology" and Sony highlights this in their presentations and in the literature. I don't know if it is deconvolution or something else. Image processing is not an area of expertise for me, so it's not clear to me if deconvolution could even be done before demosaicing.

I can't find a definitive statement of whether it is applied to the RAW, but the implication is that it is:





An interview with their design team has the most in-depth discussion of this feature that I've been able to find where the source is directly from Sony: http://dc.watch.impress.co.jp/docs/news/interview/20131122_623858.html (open in Chrome and then let it translate and then search for 'diffraction' - not a great translation unfortunately). In every Sony statement mentioning it they clearly attribute the diffraction-reduction to the in-camera processor. This interview additionally adds that it factors in the lens aperture (as expected) and that they feel it gives about 2 stops better sharpness with respect to diffraction.



Dec 29, 2013 at 07:42 PM
Taylor Sherman
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p.149 #18 · p.149 #18 · Official: Sony A7 and A7R Fullframe Mirrorless


Regarding the flares - I've also seen that with the G90 twice now, though in both cases I didn't have a hood attached. And it's pretty "naked" without the hood attached, so it'd be premature to say it's a camera problem. So I guess why am I posting this? but it looked very similar to what you show above - diffuse-source (eg just "brighter over there"), big fuzzy blob on the screen.



Dec 29, 2013 at 08:20 PM
mahlemiut
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p.149 #19 · p.149 #19 · Official: Sony A7 and A7R Fullframe Mirrorless


I used the hoods in all cases. It can be prevented by using something in addition to the hoods, but makes shooting with the affected lenses more uncomfortable. Bit sad, as the sensor really can give great results.


Dec 29, 2013 at 09:16 PM
philip_pj
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p.149 #20 · p.149 #20 · Official: Sony A7 and A7R Fullframe Mirrorless


There have been a few users reporting better results from Sony's maligned IDC - the latest vsn presumably. Perhaps things have changed in the final release of the a7/a7r profile from Adobe but this is interesting, for Charles and others:

http://www.leica-boss.com/2013/11/lightroom-adobe-camera-raw-vs-sony-image-data-converter-for-a7-and-a7r-raw/




Dec 29, 2013 at 09:52 PM
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