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A7/A7r - performance with WA RF lenses
  
 
sebboh
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p.59 #1 · A7/A7r - performance with WA RF lenses


edwardkaraa wrote:
The A7R is designed to be used with FF ZA glass via adapters, at least one of which has a SLT mirror and PDAF sensors. This is one case where different registration would screw up AF. It is true though that we are just speculating, but IMO there are more chances than not that the sensor cover is as thick as the A7. Just look at how much trouble Kodak and Leica had with IR and what not because their cameras have really no AA not the gimmick of Nikon.


that's true, i always forget about the mirrored adapters. i think they allow non lens specific micro adjust which may be able to overcome any small differences in cover glass? also, isn't the IR filter usually separate from the AA? both can contribute to the problem, and i haven't heard anything about the IR filter in the a7(r).




Nov 03, 2013 at 05:16 AM
edwardkaraa
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p.59 #2 · A7/A7r - performance with WA RF lenses




Probably they could do that if the adapter knows what body it is mounted on. As for corner smearing, Leica had not only to remove the AA filter but also use a very thin IR filter that causes some problems with black fabrics.



Edited on Nov 03, 2013 at 06:18 AM · View previous versions



Nov 03, 2013 at 05:57 AM
michaelwatkins
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p.59 #3 · A7/A7r - performance with WA RF lenses


I'm confused. See this simplistic diagram:

A7

LENSM__CAASS

A7r
LENSM_____CSS


LENS
M - Mount
C - Cover
AA - AA filter
SS - rest of sensor package

Can't there simply be more dead air between mount and cover, to make up for the missing AA layer, in the A7r? If so, doesn't that mean the LA-EA4 can work equally well on either without resorting to inserting "fillter" layers?

I guess I'm still stuck in the film days where the focal point (I thought) was on the film plane so I'm assuming the same remains true and the Sensor can remain a constant distance away from mount. Too simplistic?



Nov 03, 2013 at 06:06 AM
rcholas
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p.59 #4 · A7/A7r - performance with WA RF lenses


michaelwatkins wrote:
Can't there simply be more dead air between mount and cover, to make up for the missing AA layer, in the A7r?


No, because air and glass as well as AA crystals have different refraction indices.
A competent and lucid exposition of the implications of the refraction index difference is provided by Bruno Masset here.



Nov 03, 2013 at 05:13 PM
michaelwatkins
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p.59 #5 · A7/A7r - performance with WA RF lenses


Thanks for that, I remember reading that not long ago, and this prompts me to toss out another layman question.

Could the different microlens package on the A7r have been tuned to compensate for the missing AA layer such that Sony would not have to resort to putting in what is effectively a glass spacer layer?




Nov 03, 2013 at 05:32 PM
freaklikeme
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p.59 #6 · A7/A7r - performance with WA RF lenses


edwardkaraa wrote:
The A7R is designed to be used with FF ZA glass via adapters, at least one of which has a SLT mirror and PDAF sensors. This is one case where different registration would screw up AF. It is true though that we are just speculating, but IMO there are more chances than not that the sensor cover is as thick as the A7. Just look at how much trouble Kodak and Leica had with IR and what not because their cameras have really no AA not the gimmick of Nikon.


It seems to me that they would be able to program the LAEA4 for the registration differences, if they were indeed there, and compensate for them.

Does the filter stack have to be the same thickness to achieve the same results? Is it not possible to use a different material with different refractive properties to achieve the same results, even if it forced another design change, like off-set microlenses at the edges of the sensor?



Nov 03, 2013 at 06:11 PM
edwardkaraa
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p.59 #7 · A7/A7r - performance with WA RF lenses



freaklikeme wrote:
It seems to me that they would be able to program the LAEA4 for the registration differences, if they were indeed there, and compensate for them.

Does the filter stack have to be the same thickness to achieve the same results? Is it not possible to use a different material with different refractive properties to achieve the same results, even if it forced another design change, like off-set microlenses at the edges of the sensor?


Indeed it was mentioned by the suede that the sensor cover of the Leica M9 (that is 0.8mm thick as mentioned in the linked article above) is of cheap low quality glass and that if Leica would've opted for a more expensive glass it would have been possible to make it thinner with better IR cut performance. So we have no idea what kind of glass quality Sony has opted for, and what kind of refractive index it has.



Nov 03, 2013 at 06:26 PM
uhoh7
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p.59 #8 · A7/A7r - performance with WA RF lenses


rcholas wrote:
A competent and lucid exposition of the implications of the refraction index difference is provided by Bruno Masset here.


OK, so all we need to do is hack the bionz-x and inject the proper deconvolution.

who's with me?

On a related note, seems very thin glass commercially available:
http://www.us.schott.com/advanced_optics/english/products/optical-materials/thin-glass/thin-glass-af-32-eco/index.html

Remind me why we need glass over the sensor at all? Protection?



Nov 03, 2013 at 06:57 PM
sebboh
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p.59 #9 · A7/A7r - performance with WA RF lenses


uhoh7 wrote:
OK, so all we need to do is hack the bionz-x and inject the proper deconvolution.

who's with me?

On a related note, seems very thin glass commercially available:
http://www.us.schott.com/advanced_optics/english/products/optical-materials/thin-glass/thin-glass-af-32-eco/index.html

Remind me why we need glass over the sensor at all? Protection?


it seems extremely unlikely that leica actually uses deconvolution methods based on lens design. lot of people have shot the same lens with and without giving the camera info on what lens it is and noted the only differences were in vignetting and color.




Nov 03, 2013 at 07:08 PM
rcholas
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p.59 #10 · A7/A7r - performance with WA RF lenses


michaelwatkins wrote:
Could the different microlens package on the A7r have been tuned to compensate for the missing AA layer such that Sony would not have to resort to putting in what is effectively a glass spacer layer?


The short answer is no.

  1. A microlens improves a pixel's angular response, thereby reducing corner vignetting.
  2. A microlens also reduces the tilt of the light rays going through the color cells of a Bayer filter array, and thus reduces the color smearing caused by those light rays that are so tilted that they go through one color filter cell e.g. red and land in the photodiode area of an adjacent cell e.g. blue.

Thus, microlenses only affect the signal response on a per-pixel basis.

Microlenses therefore can't have any effect on the corner smearing caused by the aberrations affecting lenses that haven't been designed to take into account the refraction effects of an IR+AA filter stack: microlenses are not intelligent, and cannot distinguish between an aberrated "smear" that happens to cover multiple pixels and, say, a similarly-sized blur of a small out-of-focus object imaged by a well-corrected lens e.g. the new Sony Zeiss Sonnar FE 55mm F/1.8. In both cases, the resulting pixel pattern will therefore remain a blurry blob.



Nov 03, 2013 at 08:36 PM
 

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rcholas
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p.59 #11 · A7/A7r - performance with WA RF lenses


uhoh7 wrote:
Remind me why we need glass over the sensor at all? Protection?


It's highly unlikely that the diaphanous multi-layer web of silicide and metal interconnects that are less than 100 nanometers wide, deposited on static electricity-sensitive, microscopic semiconductor structures, would survive any attempt e.g. to use a sensor swab to remove the inevitable dust that accumulates on an interchangeable lens camera's sensor...



Nov 03, 2013 at 08:37 PM
uhoh7
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p.59 #12 · A7/A7r - performance with WA RF lenses


rcholas wrote:
It's highly unlikely that the diaphanous multi-layer web of silicide and metal interconnects that are less than 100 nanometers wide, deposited on static electricity-sensitive, microscopic semiconductor structures, would survive any attempt e.g. to use a sensor swab to remove the inevitable dust that accumulates on an interchangeable lens camera's sensor...


Fair enough, but what about a single sheet of that .03mm Schott glass I link to above?

or even better their "ultra thin":
ultra-thin form that is also available in various types and thicknesses of between 25 and 100 μm.
http://www.us.schott.com/advanced_optics/english/products/wafers-and-thin-glass/glass-wafer-and-substrates/ultra-thin-glass/index.html

jeez Sony, do I have to think of everything?

I mean I apreciate you made my FF nex for me, in spite of all the poo pooers around here, but I assumed you had your sensor shit together...



Nov 03, 2013 at 08:53 PM
uhoh7
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p.59 #13 · A7/A7r - performance with WA RF lenses


this just in: sroute over at DP nex forum will be shooting the A7r in Vancouver, BC this coming week and is willing to try whatever he can get his hands on.

who do we know near there?



Nov 03, 2013 at 09:29 PM
michaelwatkins
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p.59 #14 · A7/A7r - performance with WA RF lenses


^^ That'd be me.

There are two Sony A7/A7r hands-on events coming up over the next seven days in Vancouver, and one in Victoria, BC. The cameras will be available for a few hours starting in the late afternoon on two different dates/locations plus Victoria makes three.

Sony tells me they'll be bringing a variety of adapters (metabones I believe) to each event; there may be some alt-glass made available by the event hosts. PM me for time and location details if interested. Let's test some alt-glass!



Nov 03, 2013 at 11:00 PM
hakkamukka
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p.59 #15 · A7/A7r - performance with WA RF lenses


If you are planning on trying out Leica M mount glass, I suggest you try to bring your own adapter. It may not be the case for you and that Sony Canada/North America is more organised but I have attended two events in Australia and they only had the Metabones Canon EF to E mount adapter on hand. They also had Canon EF glass to try it with.

Again, may not be the case for the events up there but if you can get your hands on or you already have one, bring it just in case.





Nov 04, 2013 at 12:56 AM
alundeb
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p.59 #16 · A7/A7r - performance with WA RF lenses


edwardkaraa wrote:
The A7R is designed to be used with FF ZA glass via adapters, at least one of which has a SLT mirror and PDAF sensors. This is one case where different registration would screw up AF. It is true though that we are just speculating, but IMO there are more chances than not that the sensor cover is as thick as the A7. Just look at how much trouble Kodak and Leica had with IR and what not because their cameras have really no AA not the gimmick of Nikon.

sebboh wrote:
that's true, i always forget about the mirrored adapters. i think they allow non lens specific micro adjust which may be able to overcome any small differences in cover glass? also, isn't the IR filter usually separate from the AA? both can contribute to the problem, and i haven't heard anything about the IR filter in the a7(r).


Hello guys, it is monday morning at my place, and maybe I don't get at all what the problem is with registration distance and AF with mirrored adapters.
You seem to have constructed a problem that does not exist. Different registration with true AA less filter stack is the solution to the problem, not the problem. Not?



Nov 04, 2013 at 07:34 AM
r.gil
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p.59 #17 · A7/A7r - performance with WA RF lenses


I have the Contax Biogon 21, 28 and 45mm lenses
can someone tell me if they would work full frame on the 7r
and what adapter will be the best for this combo?
thanks



Nov 04, 2013 at 01:32 PM
naturephoto1
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p.59 #18 · A7/A7r - performance with WA RF lenses


r.gil wrote:
I have the Contax Biogon 21, 28 and 45mm lenses
can someone tell me if they would work full frame on the 7r
and what adapter will be the best for this combo?
thanks


If you are talking about the G lenses, at this point the 45mm looks to be quite good. The other 2 not so good at this point, but we will need more tests run and reported specifically for the A7r. So far we have seen problems with the 21 and the 28 I believe along the edges and corners.

Rich



Nov 04, 2013 at 01:39 PM
r.gil
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p.59 #19 · A7/A7r - performance with WA RF lenses


naturephoto1 wrote:
If you are talking about the G lenses, at this point the 45mm looks to be quite good. The other 2 not so good at this point, but we will need more tests run and reported specifically for the A7r. So far we have seen problems with the 21 and the 28 I believe along the edges and corners.

Rich


Thank you Rich
These are G lenses, in terms of adapter which would you recommend?
and would it make any difference between the 7 and 7r



Nov 04, 2013 at 02:14 PM
fotoingo2
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p.59 #20 · A7/A7r - performance with WA RF lenses


Hey Gil,
nobody can tell you right now how the lenses will work and which adapter will be the best.

You need to be patience like all of us ;-)

Hopefully Sony will deliver the cameras in November.. !



Nov 04, 2013 at 02:42 PM
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