A7RII solves symmetrical lens problems?

[storyteller]

Interesting tidbit. A summary of the Chinese review posted several weeks ago on SAR (look in the comments there are still no subtitles on the video) states that the BSI sensor improves the corner performance of symmetrical lenses—that's why the reviewer has the segment with the Contax G 28mm—which I can attest is a difficult lens for the A7 series so far. That said, keep a healthy dose of skepticism until further testing is done. 

[OldNoob]

Am i understanding? the Sensor actually is doing the correction? or the software driving it? So distortion correction automaticly in RAW?

[yali]

No, I think he's talking about color shifts an similar problems that arose when using old film lenses on the A7 digital sensors. Due to the big angle the lightrays hit the sensor there were some of these color shifting problems. theory is that the BSI sensor will solve that problem as the photodiodes are sensitive to a wider angle of light.

[Philber]

No review that I have seen discusses A7RII performance with legacy lenses. This unexpected, and my guess is that this is due to a Sony embargo until the camera ships. Similarly, no-one is saying anything about DR: is it improved with the new sensor? Thus my feelign that Sony have embargoed certain topics.

[saxo]

This is an interesting point for many photographers who aim to use wide angels with M-mount on a Sony alpha 7. Until now, this was only possible with the A7s, and even there some lenses suffer from color shift in the corners.

 

I'm interested in the performance of the Elmarit 3,4/21mm ASPH, a perfect lens, nearly symmetric design, with very little distortion. In addition I would like to see how the little summilux 35mm performs. Yes, there is the Zeiss 1,4/35mm, which is nearly perfect, but it is a big and heavy lens. The Leica summilux fits far better to the tiny  A7-body.

Any suggestions where I can get the information?

 

Or is Sony just try to keep it secret. What for? I don't buy a pig in a poke.

[storyteller]

The camera just isn't widely available even to reviewers. No doubt there will still be heavy vignetting (looking at samples online this is clear). I suspect no reviewer is willing to stake their reputation until they can do extensive tests with their own lenses and put SD cards in the camera. I doubt you will get perfect performance but it may improve over the A7S!

[saxo]

Vignetation isn't such a problem, could be solved by postprocessing software such as cornerfix. The main problem is the color shift, where correction is more difficult IMHO.

 

We will see in a couple of weeks.

 

Nevertheless Sony has done a great job. It carefully listened to the criticism made on the A7r. This is not always the case, e.g. if I look at Canon.

[Golem]

I'm sticking with retrofocus lenses

and not worrying myself about how

to use Leica lenses etc.

 

Even in the film era, a retrofocus

offered more even illumination, as

well as minimizing "egg-headed"

corner imaging, characteristic of

short back-focus designs.

 

`

[foto-fanatic]

Could be a big boon for leica wide angle shooters yes?

[saxo]

 

Even in the film era, a retrofocus

offered more even illumination, as

well as minimizing "egg-headed"

corner imaging, characteristic of

short back-focus designs.

 

`

 

Ever tried the Hasselblad SWC? The prototyp of a symmetrical lens.

[saxo]

problably the issue is solved, test by 3d-kraft:

 

http://3d-kraft.com/index.php?option=com_content&view=article&id=177&catid=40&Itemid=2

[Golem]

Ever tried the Hasselblad SWC?

The prototyp of a symmetrical lens.

SWC was my general purpose

snapshot camera for decades.

 

But it was only a bit wider than

mid-wide. So, for really wide

.... and really egg-headed ....

snaps I also used a Veriwide

with a 4x5 back, also a 47 SA

on a 4x5 Technica.

 

Best fun with the 4x5 backs

was with my Horseman 6x12

rollfilm holder :-)

 

 

`

[OldNoob]

Suppose one could use medium format lenses to resolve this. jk.

[Golem]

In general, with digital cameras, more back focus

is more betterer. Why do you think Zeiss makes a

DISTAGON 50 as a normal lens for 24x36mm digital ?

 

In essence, this amounts to using a medium format

lens on a miniature format ... except they save a

a bit of weight and a bunch of sheckels by using

smaller diameter elements and barrels, since the

outer regions of the medium format coverage will

not be recorded with the smaller sensor. IOW it's

a MF lens, but will vignet on a MF camera cuz the

outer reaches of the lens diameter are missing.

 

If Sony has massaged the lens array on the A7R-2

sensor to favor reduced back focus, then if Sony

offers any really long FL, these will incorporate

some sort of relay optics [in effect] at the rear

of those lenses, so as to mimic the angle that the

corners of the sensor's lens array is designed

to favor. Not really rocket science, but legacy

glass will then work well at short FLs and poorly

at longer FLs.

 

 

`

[saxo]

Sony obviously hasn't reduced the thickness of the sensor's frontfilter. Therefore no improvment of smearing using M-lenses.

 

I can't understand the benefit of a thick sensor filter. I can only see disadvantages: no compact lens design possible.

 

The only way to escape is Kolarivision, another 500,--$

 

Or waiting for the new Leica at the end of the year....

[Guest all8]

One advantage of a think sensor filter is that adapted lenses don't work so well. Therefore I have to buy a Batis 25mm rather than waste my time using my existing Leica 28mm. And I don't even bother dreaming about a Leica 50mm APO any more since that damm Loxia 50mm is just as good for 1/7th the price. Well, to be honest, I see some advantage for Sony, some for Zeiss, some at least some for me (if you look hard enough at my big picture) ... and none for Leica. I find that kind of funny to be honest, even if I'm not so sure I'm happy about it.

 

I'm sure its deliberate on Sony's part      

[saxo]

The disadvantage is not, that you can't use Leica M-lenses (R-lenses are no problem). It's just you can only use retrofocus lenses at all. This results in bulky wide angle lenses, e.g. the Zeiss FE 1,4/35. Ever compared the size to the Leica 1,4/35?

 

Sony builds a small camera for big lenses..... great idea!

[3D-Kraft]

It's just you can only use retrofocus lenses at all. This results in bulky wide angle lenses, e.g. the Zeiss FE 1,4/35. Ever compared the size to the Leica 1,4/35?

Do you find the WATE or the Skopar 21/4 or the Heliar 12/5.6 bulky?

[saxo]

OK, there are a few exceptions, like always. The Wate was acceptable in size, so not produced anymore, but not realy small.

 

There are many other examples, like the 3,4/21mm. A perfect super-wideangel lens with only minor optical failures. The 3,8/18, 2,8/28, 3,8/24....

 

Could you tell us anything about my question: why is the thick sensor-filter of advantage? Wouldn't a thin filter do the trick?

[Guest all8]

Is it really thick, or just normal? http://www.lensrentals.com/blog/2014/06/sensor-stack-thickness-when-does-it-matter

 

I would suggest that Leica makes sensors with a thin filter because they need their camera to work with their lenses. Leica has had lots of trouble with its sensor filters ... which makes you wonder a little. Sony does not have this constraint so probably they choose the best solution for their lenses.

 

AFAIK the WATE is still available, not sure if is good, or really good, or the best, on the A7? It would be an acceptable alternative for me ... but I hope a Loxia alternative is arriving later this year.

[saxo]

Thanks for the link!!

 

The thikness of the sensor-stack vary significantly, even Sony shows differences of 4-times (0.6-2.8). Leica M9 was 0.8. So Sony produces very different stack-sizes.

 

You are right, I mixed the MATE, the Tri-Elmar 28-35-50, which is out of production with the 16-18-21, called WATE.

[Philber]

In my opinion, WATE is very, very good, but not quite as good as the SE 21 f:3.4 or Elmar 24 f:3.8. And, yes, a wide Loxia is coming later this year.