p.31 #1 · A thinner sensor stack may be possible after all!
Steve Spencer wrote:
Nico,
How sure are you that your adapters isn't too thin? The Z* 21 f/2.8 seems to under perform when the sensor is too thin (i.e., when the lens is too close to the sensor). Non-floating element lenses like the Olympus OM 24 f/2.8 and the Zeiss C/Y 28 f/2.8 aren't nearly as affected by a thin sensor. In this case i suppose the conversion might have brought the sensor a smudge too close and that is affecting the 21 (which is very sensitive to this issue) and not the OM 24 or Zeiss 28.
Hello Steve
That is a very good point actually and that may explain the problem if the Zeiss 21ZF lens indeed has a floating element. After the modification the Zeiss reaches infinity at around the 1.5meter mark.
Have just temporarily shimmed my adaptor and the Zeiss now reaches infinity at the intended point and it performs perfectly again
p.31 #4 · A thinner sensor stack may be possible after all!
After shimming the adaptor to take into account the fact that the Zeiss 21/2.8 ZF2 has a floating element (thanks Steve!) the lens performs perfectly on the Kolarivision modified Sony A7R.
Using SLR lenses therefore should not cause any problems after modification as long as your adaptors are calibrated properly for infinity when using lenses with floating elements.This will also be the case for an unmodified A7R.
I have uploaded a comparison from f2.8 to f11 between the Zeiss 21/2.8ZF2 against the Voigtlander 21/1.8 which are my sharpest lenses at the moment. The Voigtlander seems to manage to generate more moire than the Zeiss which I suspect technically indicates that it is resolving more fine detail however the Zeiss suffers less from diffraction at f11
p.31 #5 · A thinner sensor stack may be possible after all!
Shots from yesterday afternoon.
A7rM and M28 Elmarit v3
Nico, excellent test shot comparisons with Zeiss 21/2.8 and CV 21/2.8. The Zeiss 21 does not seem to have the sharpness compared to the CV 21, but I am sure the finer rendering would be there.
Great observations regarding the adapter thicknesses!! I have measured accurately the thicknesses of the different adapters, and found that the Novoflex being the best made IMO tends to be thinnest adapters. The stock Metabones that Sony provides is about 1mm thicker, and on a number of lenses I cannot reach infinity.
Where possible I use the VM-E adpater, as I love the close focus feature. The adapter focus ring tends to be stiff, which is great as I now focus wide open at infinity with M lens set at infinity stop, and adjust the VM-E adapter to be focused at infinity. I rarely have an issue with the VM-E moving after, but ideally it would be good to have a focus lock so there would be no possibility of movement. This allows the fine tuning of the adapter thickness to suit assuming there is no miss alignment. For now I have been marking the VM-E positions for different lenses as it only needs a marginal adjustment.
I agree Nico, the thin filter modification is great with the A7r
p.31 #6 · A thinner sensor stack may be possible after all!
nicoimages wrote:
After shimming the adaptor to take into account the fact that the Zeiss 21/2.8 ZF2 has a floating element (thanks Steve!) the lens performs perfectly on the Kolarivision modified Sony A7R.
Using SLR lenses therefore should not cause any problems after modification as long as your adaptors are calibrated properly for infinity when using lenses with floating elements.This will also be the case for an unmodified A7R.
Not to add more to your plate, but I wonder if at your convenience, you could re-try the TS-E 24 with the correctly shimmed adapter?
p.31 #7 · A thinner sensor stack may be possible after all!
The Zeiss 21 does not seem to have the sharpness...
I did notice it as well. My perfectly spot-on F to E adapter doesn't reach infinity now with some lenses, Zeiss 2.8/21 (gone by now!) including. This morning I took few shots with Leica R 35 and again, no infinity reach, where Zeiss Biogon 2/35 on Cosina VM-E adapter passes infinity stop for easy focusing. Good catch Nico! Gotta try my other F to E adapters to confirm it.
Speaking of Biogon 2/35; the shot below was taken WO for horizontal focussing adjustment and I forgot to switch it back to f/8. Well, Biogon at its worst
p.31 #8 · A thinner sensor stack may be possible after all!
Jack and Charles...I just picked an A7r with only 2500 actuations, and my first order of business is to send it off to KolariVision for the mod. Looking forward to using my Biogon as well. Do either of you know(or anyone for that matter!) how my ZM 50's Sonnar and Planar will benefit from the mod?
p.31 #9 · A thinner sensor stack may be possible after all!
Greggf wrote:
Jack and Charles...I just picked an A7r with only 2500 actuations, and my first order of business is to send it off to KolariVision for the mod. Looking forward to using my Biogon as well. Do either of you know(or anyone for that matter!) how my ZM 50's Sonnar and Planar will benefit from the mod?
Congrats Greg! I no longer have the ZM 50 Planar or Sonnar, but all my M lenses I have tested so far appear to have improved. My technique with M adapters has changed somewhat as I mentioned above. I use the VM-E and fine tune for infinity on each lens I use.
p.31 #10 · A thinner sensor stack may be possible after all!
charles.K wrote:
Congrats Greg! I no longer have the ZM 50 Planar or Sonnar, but all my M lenses I have tested so far appear to have improved. My technique with M adapters has changed somewhat as I mentioned above. I use the VM-E and fine tune for infinity on each lens I use.
I too have the VM-E and love it. I'm actually really looking forward to using my OM 100/2 and especially my new 75 Summarit!
p.31 #11 · A thinner sensor stack may be possible after all!
Greggf wrote:
Jack and Charles...I just picked an A7r with only 2500 actuations, and my first order of business is to send it off to KolariVision for the mod. Looking forward to using my Biogon as well. Do either of you know(or anyone for that matter!) how my ZM 50's Sonnar and Planar will benefit from the mod?
Gregg,
I have both Zeiss 50's and will make and post some shots, but don't have before/after capabilities at this point.
Did some stitching tests with the Hartblei/Zeiss 80mm TS today and will add to the Flickr pool, but they lack artistry. ;-)
p.31 #12 · A thinner sensor stack may be possible after all!
Thanks Michael. I'm sending the R off on Monday. Not sure what the turn around time is? I love my Sonnar, and that's just on the 7. I bet it rocks on the R!
Gregg
p.31 #13 · A thinner sensor stack may be possible after all!
Greggf wrote:
Jack and Charles...I just picked an A7r with only 2500 actuations, and my first order of business is to send it off to KolariVision for the mod. Looking forward to using my Biogon as well. Do either of you know(or anyone for that matter!) how my ZM 50's Sonnar and Planar will benefit from the mod?
Congrats Gregg!
I hope you wont use Sonnar stepped down!
Planar and other lenses from film era should benefit, especially rangefinders.
Make sure you adjust (reduce) sharpening at various stages of PP as it maybe less needed. In fact, presets from A7 should be revised for modded A7R.
p.31 #14 · A thinner sensor stack may be possible after all!
About to send my A7r for conversion, excited! I just emailed Kolari to know the current lead time. Hope to see some improvement on the Nokton 35/1.2II, based on this, even if on my A7r the corners with the Nokton seem much better than on this comparison:
p.31 #15 · A thinner sensor stack may be possible after all!
nicoimages wrote:
Another SLR lens that seems to have improved after conversion is the Contax Carl Zeiss Distagon 28/2.8 - to my great disappointment this lens was never as sharp as it could be particularly in the corners and had an odd mid zone dip before the conversion. It now is very good at f8 across the frame and has that amazing Zeiss microcontrast - the link below is a series of infinity images taken at all apertures
Do you have a similar series with the same lens pre modification?
I would be very interested in a direct a7 vs a7m comparison with older SLR lenses, we all know that M-glass improves a bit to a lot but I still have no clear image on how the filter stack affects image quality with SLR lenses.
I remember this older post by thesuede: I never had the opportunity to run same (or at least very similar) lenses on the D3x and the A850 while I had them both, but my definite impression was that the D3x was several notches better in both sharpness and "micro-contrast" than the Sony. Even when the D3x was used with fairly standard lenses.
1) the Sony AA filter is made from a much cheaper material (probably quartz crystal, never had one sent in for analysis...) :-) - and this makes the AA filter a LOT thicker to get the same spread. This affects corner sharpness and microcontrast in a very bad way. Same problem that the NEX7 has.
Corner sharpness goes due to increased astigmatism, increased AA angle response and an attenuation of spherochromatism and spherical aberrations.
2) The quarts crystal is harder to get a perfect surface on, and it has higher internal dispersion. This combined with the increase in spherical aberration makes the higher MTF's at every frequency suffer. It's like having a "glass roof" on microcontrast - "here, but no further!" :-)
The A850/900 can still have a very good MTF50 resolution after sharpening, especially since the resolution is only measured in the exact center of the frame... But the MTF70 does drop like a bowlingball in free flight as soon as you approach the sensor resolution. And the MTF 50 drops pretty soon as you leave the image center....Show more →
Which could hint at a significant imrovement (assuming that the a7 and a900 filter stack are very similar). But as I said so far I have not seen a good comparison of SLR glass between and unmodified a7 and and a7m or even a Leica M240.
p.31 #17 · A thinner sensor stack may be possible after all!
Phillip Reeve wrote:
Do you have a similar series with the same lens pre modification?
Hello Philip
I don't have similar test images unfortunately any more to make the comparison a bit more meaningful. I did however stop using the Distagon for landscapes as it was just not sharp enough in the corners compared to other lenses I had at the time such as the Nikkor 28/1.8G . The difference is very subtle with this lens however it is there particular in the extreme corners that never sharpened up enough prior to the modification even when considerably stopped down.
Thanks
Nicholas
P.S really enjoy reading your site and looking at your images
p.31 #18 · A thinner sensor stack may be possible after all!
JaKo wrote:
Speaking of Biogon 2/35; the shot below was taken WO for horizontal focussing adjustment and I forgot to switch it back to f/8. Well, Biogon at its worst
Interesting! The Loxia 35/2 seems much better in the corners wide open on my unmodified a7. Perhaps the ZM Biogon is still affected by the thinner filter stack, compared to film, which it was intended for?
p.31 #19 · A thinner sensor stack may be possible after all!
rscheffler wrote:
Not to add more to your plate, but I wonder if at your convenience, you could re-try the TS-E 24 with the correctly shimmed adapter?
Hello Ron
After seeing how the Zeiss 21/2.8ZF performed when the adaptor had the correct length, I spent a lot of time yesterday re-shimming the Viltrox Canon to FE adaptor.
It turned out to be a bit of a challenge as I had to ensure that the lens contacts still were in contact with the adaptor electronics after shimming.
Happy to say that the performance of the TS-E 24MKII has improved considerably now and the field curvature is almost gone. Will upload images taken at infinity from my roof terrace as soon as the weather improves and I have managed to get the shims even enough.
p.31 #20 · A thinner sensor stack may be possible after all!
nicoimages wrote:
Hello Ron
After seeing how the Zeiss 21/2.8ZF performed when the adaptor had the correct length, I spent a lot of time yesterday re-shimming the Viltrox Canon to FE adaptor.
It turned out to be a bit of a challenge as I had to ensure that the lens contacts still were in contact with the adaptor electronics after shimming.
Happy to say that the performance of the TS-E 24MKII has improved considerably now and the field curvature is almost gone. Will upload images taken at infinity from my roof terrace as soon as the weather improves and I have managed to get the shims even enough.
Many thanks
Nicholas
...Show more →
good to know. I had a Canon Ef 16-35/4 IS vith the viltrox adapter but I returned it because of inacceptable field curvature and worse than expected corner sharpness. Where do you get your shims from?
