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Sony A7 and A7r Full Frame with Canon Lenses
  
 
marc aurel
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p.94 #1 · p.94 #1 · Sony A7 and A7r Full Frame with Canon Lenses



A7R+TS-E 24: Internal reflections in Metabones III adapter and what could help - Part 2: how to do it

The geometry of the adapter is not very simple, so it's a bit tricky to do. Below are images of how it looks after the modification.
I made a cutting pattern which consists of several perts (see below). It's not absolutely precise, but it worked well. The jpg with the cutting pattern is scaled 1:1, so you could use it to try. Your own risk of course... ubt the self-adhesive velour i used could be removed without problems.
At first I covered every surface inside. Then I noticed that at a shift of more than 10mm the velours interfered with the optical beam path (the opening of the adapter is just about 36x24mm). When shifted up (rise), the lowest part of the image bottom went darker. When shifting down (fall), it went darker on top.
So I took off the velour on one surface (marked green in the cutting pattern), but only the one that interfered with the shift up (cause i don't use more than 10mm of shift down). The problem was gone and it didn't visibly change the image quality. Either this was not the problematic surface, or it is sufficient to treat most of the surfaces to prevent a ping-pong-effect of reflections. Image 2 shows how that looks. You can also see that - despite of the matte black finishing - the metal does reflect.
Maybe it's not to everyones taste do such things - but now i get the best image quality available for this sensor size when shift is needed.

marc aurel

















Dec 19, 2013 at 06:23 PM
Fred Miranda
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p.94 #2 · p.94 #2 · Sony A7 and A7r Full Frame with Canon Lenses


Thanks for posting this here Marc!
I encountered the same low contrast issue with the TS-E 17mm even with the lens unshifted.
I glued your printed 1:1 diagram on the back of a black felt sheet and was able to precisely make the cutouts. It fits the adapter great.
I am waiting for a new Metabones copy to post more tests because the one I have is clearly tilted.
Fred







Dec 19, 2013 at 06:33 PM
AGeoJO
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p.94 #3 · p.94 #3 · Sony A7 and A7r Full Frame with Canon Lenses


Marc, you did really a good job putting that sticky velour on the adapter . Thank you also for the instruction on how to do it .


Dec 19, 2013 at 06:34 PM
KiboOst
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p.94 #4 · p.94 #4 · Sony A7 and A7r Full Frame with Canon Lenses


wow, very nice idea and job done with the velour. Seems a lot better indeed !

I wouldn't be surprised if we see a metabones v4 like this in a few months. I guess A7R users are putting more stress on such adapters and will find all misconceptions ;-)

Really a nice thread with lot of infos and everyone tries and finding, in a constructive discussion. Really appreciated, thanks all ;-)



Dec 19, 2013 at 06:50 PM
snapsy
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p.94 #5 · p.94 #5 · Sony A7 and A7r Full Frame with Canon Lenses


Awesome information and diagram Marc. I wonder why Metabones mills that threaded pattern in the cylinder of the adapter. Even though it's painted black it's rather reflective on my copy.


Dec 19, 2013 at 06:58 PM
AGeoJO
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p.94 #6 · p.94 #6 · Sony A7 and A7r Full Frame with Canon Lenses


FYI, the RJC adapter has felt lining at the side of the rectangular light path opening but not at the front or rear of the baffle. I believe that is more crucial in suppressing contrast robbing flare.


Dec 19, 2013 at 07:19 PM
beetlephoto
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p.94 #7 · p.94 #7 · Sony A7 and A7r Full Frame with Canon Lenses


marc aurel wrote:
Hi beetlephoto,

I wrote the topic on Luminous Landscape Forum you linked:

A7R+TS-E 24: Internal reflections in Metabones III adapter and what could help

I post it here to share it with the ones who are not registered on LL. So:

I made a comparison with TS-E24 II on A7R and 5DIII, using shift. In the centre of the unshifted lens, the A7R has more resolution. Most obvious in the meander of the tympanon and the grid in the window. In the extreme corners of the shifted image resolution of both cameras is very close.
But additionally there is a degradgation of contrast in
...Show more
Awesome, thanks so much!!! I've printed your diagram and will cut my velours tomorrow. Great tutorial.



Dec 19, 2013 at 09:07 PM
Pixel Perfect
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p.94 #8 · p.94 #8 · Sony A7 and A7r Full Frame with Canon Lenses


Just got a news letter from one of the guides that took us to Iceland who has a D800 and recently bought the A7R and he has been posting his finding so far. He says his adapted Nikon lenses and Zeiss for Nikon lenses are tack sharp and has not had any adapter issues. Can't recall the adapter off the top of my head. He's write up is very good and he's still doing field testing. It's not all rosess though but he wants to do more testing before passing final judgement. One thing is battery life is pathetic and he said waking the camera up form sleep can take a random amount of time, but often many seconds, often quickly.


Dec 19, 2013 at 10:46 PM
Sneakyracer
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p.94 #9 · p.94 #9 · Sony A7 and A7r Full Frame with Canon Lenses


Fred Miranda wrote:
Thanks for posting this here Marc!
I encountered the same low contrast issue with the TS-E 17mm even with the lens unshifted.
I glued your printed 1:1 diagram on the back of a black felt sheet and was able to precisely make the cutouts. It fits the adapter great.
I am waiting for a new Metabones copy to post more tests because the one I have is clearly tilted.
Fred


Have you tried adjusting those 6 screws holding the lens mount in place? Looks like a place where the mount can be off spec very easily.

But, reading between the lines of Roger Cicala's test HERE I think there might be something else going on. Look at his results with the D800E and Nikon glass. Corner sharpness is almost 50% less than center sharpness (Avg MTF50 Lp/IH numbers). That was the case with the Zeiss 50mm F2 lens and the Nikon 35mm 1.4 at optimum apertures, 2 of the best lenses for the Nikon. So the problem might the sensor/physics.

I was impressed with the results of the A7R and the native Sony FE lenses. Wow.



Dec 20, 2013 at 12:23 AM
mco_970
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p.94 #10 · p.94 #10 · Sony A7 and A7r Full Frame with Canon Lenses


snapsy wrote:
Awesome information and diagram Marc. I wonder why Metabones mills that threaded pattern in the cylinder of the adapter. Even though it's painted black it's rather reflective on my copy.


Thanks Marc! I am adapting from Nikon to A7, and am having a lot of problems. I note that my Fotodiox Pro has the same threaded pattern in the rings. I am going to cover that and see if it helps. The threaded pattern is quite reflective in the Fotodiox, too.

Interesting thread, and kudos to you on your ingenuity.



Dec 20, 2013 at 01:38 AM
 

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marc aurel
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p.94 #11 · p.94 #11 · Sony A7 and A7r Full Frame with Canon Lenses


Thanks everybody for the positive feedback!
Glad to hear that so many are interested.

Marc



Dec 20, 2013 at 11:32 AM
RCicala
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p.94 #12 · p.94 #12 · Sony A7 and A7r Full Frame with Canon Lenses


I think Marc's work is going to be extremely useful for tilt-shifts and probably help with certain other lenses. From what I've tested, though, it's not going to make a huge difference overall. I took a metabones 3 adapter yesterday and tested a Canon 24-70 f/2.8 at 70, then the 35mms I tested earlier (Zeiss f/2, Canon 35 f/2 IS). Then I painted the inside of the adapter with optical blacking and retested, then did it with fuzzy black tape according to Marc's pattern and retested. No difference in Imatest at all.

What theSuede and others said earlier is certainly the bigger issue. I've talked to two well-known lens designers, an adapter manufacturer, and someone who does sensor glass modifications about. All 3 agreed the off-axis issues are about cover glass thickness and composition.

For lenses with exit pupils near the rear (most wide angles and M mount, many others) off-axis performance isn't going to be as good as center performance. The good news is almost all tilt-shifts have exit pupils way up in the lens, so that should do better.

Edited on Dec 20, 2013 at 05:49 PM · View previous versions



Dec 20, 2013 at 11:41 AM
john_edwards
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p.94 #13 · p.94 #13 · Sony A7 and A7r Full Frame with Canon Lenses


RCicala wrote:
What theSuede and others said earlier I've talked to two well-known lens designers, an adapter manufacturer, and someone who does sensor glass modifications about. All 3 agreed the off-axis issues are about cover glass thickness and composition.



Perhaps Ziess can come to Sony's rescue with an aspherical sensor cover which would straighten out those pesky light rays.

John



Dec 20, 2013 at 01:57 PM
RCicala
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p.94 #14 · p.94 #14 · Sony A7 and A7r Full Frame with Canon Lenses


john_edwards wrote:
Perhaps Ziess can come to Sony's rescue with an aspherical sensor cover which would straighten out those pesky light rays.

John



I think some people are looking into an adapter with corrective optics. Or so I hear



Dec 20, 2013 at 04:34 PM
Fred Miranda
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p.94 #15 · p.94 #15 · Sony A7 and A7r Full Frame with Canon Lenses


RCicala wrote:
I think some people are looking into an adapter with corrective optics. Or so I hear


That is great news!

So, perhaps we will have an adapter that corrects the off-axis issues caused by the thickness of the glass?

BTW: With Marc's anti-reflective velour idea I'm getting way better contrast in the corners when using the 17mm and 24mm TS-E (shifted and unshifted). With other lenses like the the Samy 14mm or 24-70 II, there is no noticeable difference with the velour or without.
Fred



Dec 20, 2013 at 05:11 PM
RCicala
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p.94 #16 · p.94 #16 · Sony A7 and A7r Full Frame with Canon Lenses


Fred, I'm told it's fairly simple and straightforward to do - at least that's what people a lot smarter than me say. I can't follow the math once they start using all those Greek symbols and stuff.




Dec 20, 2013 at 05:48 PM
Larate
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p.94 #17 · p.94 #17 · Sony A7 and A7r Full Frame with Canon Lenses


snapsy wrote:
It'll be race between Canon's sensor engineers and Sony/Zeiss's lens designers


Will we face another race condition that will move us to a deadlock state ?
:')



Dec 20, 2013 at 06:09 PM
marc aurel
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p.94 #18 · p.94 #18 · Sony A7 and A7r Full Frame with Canon Lenses


Fred Miranda wrote:
BTW: With Marc's anti-reflective velour idea I'm getting way better contrast in the corners when using the 17mm and 24mm TS-E (shifted and unshifted). With other lenses like the the Samy 14mm or 24-70 II, there is no noticeable difference with the velour or without.
Fred



Hi Fred -
Roger Cicala reports the same. Seems like only lenses with extreme large image circle have the problem with the metabones.

I want to add another observation here: I recently bought a Zeiss-Contax PC-Distagon 35mm which I use via Adapters on 5DIII and the A7R. The Adapter for the E-Mount for A7R is by Novoflex and has a simple form: just a tube - similarly structured surface as the metabones. Even with full shift I see no degradation of contrast in the corners as with the TS-Es.

So the problem could be the geometry of the metabones: That platform before the rectangular opening begins is parallel to the rear element of the lens. Could be that the main reflections happen between that surface and the rear element (and maybe the blank metal of the bajonet of the lens).

By the way and a bit off topic:
The PC-Distagon 35mm is great on the A7R. It only offers 10mm of shift and no tilt, but the shifted corners are quiet sharp - in my eyes the extreme corners are better than the TS-E 24 II. It has more distortion, but the free Alpa plugin for Photoshop has a profile which works great. In my eyes the best option for that focal length. It's rare though and I was just lucky getting one in good condition.



Dec 20, 2013 at 06:59 PM
scott bye
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p.94 #19 · p.94 #19 · Sony A7 and A7r Full Frame with Canon Lenses


You could you black flocking material that my be better than your velour. I used it inside my Globuscope 4x5 camera. They use it in telescopes and it looks darker than the pictures you guys have posted.


Dec 20, 2013 at 10:29 PM
secondclaw
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p.94 #20 · p.94 #20 · Sony A7 and A7r Full Frame with Canon Lenses


I've been experiencing pretty awful sensor flares with Metabones3-adapted canon lenses on A7R. Is the issue really with the sensor, or is adapter playing some role in the flare? I don't have any native FE glass or another adapter to test.
This is from last night testing 24-70 MK2 ...

















Dec 21, 2013 at 04:39 PM
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