Canon FDn 35mm f/2 on Sony A7R

Canon FDn 35mm f/2 on Sony A7R

This lens was superb on the A7, how does it rate on the A7R?

This is just a quick update for the lens on the A7R. Supposedly my chart is rated conservatively for 24 MP cameras or less, so does it hold up to the 36 MP A7R? Let’s find out.

Since it is the first lens I am testing I went all the way to f/22 so you can see the quick drop off in performance above f/11. Remember, the smaller pixels on the A7R are no worse than the A7, but they appear worse relative to the max resolution on the A7R, but this is because the A7R peaks higher.

Optical Performance

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Please click on the tab you want to view. Only 1 tab may be active at a time. MTF, Distortion, and Lat CA data acquired using Imatest
MTF20 Chart maxes at vertical resolution of the sensor which is 4912 LW/PH for A7R. Anything above that is meaningless. The MTF50 chart is set at the value where the best lenses perform in the center, or about 3850 LW/PH on the A7.
Note: 4k video is 2160 LW/PH
Note: HD video is 1080 LW/PH

Comments on the Results

“This has A7R written all over it.” Is what I said about this lens in my A7 review. Does it hold true? I would say so. If anything looks worse, it is just because I adjusted my scales for the higher MP camera so they are graded against a higher standard.

A couple things to note, the actual resolution figures for the lens in the corners at large apertures and at f/11 and beyond are roughly the same as on the A7. That is, these areas were lens limited on the A7, there is no reason for them to be significantly different on the A7R (they are a little better in general because of the higher resolution sensor).

The second thing is that I might be bumping into the chart resolution. Notice that I never exceed 4912 like the A7 exceeded its max of 4000, and the central resolution is pretty flat from f/2.8 to f/8. I might be exceeding the resolution of the chart here (or finally bumping into the limits of the lens). As I test more lenses I will know for sure.

What has improved are the areas that were sensor limited on the A7, primarily the center at most apertures, and across the frame from f/4 to f/8. It isn’t bad if you shoot outside that range, but you do lose a lot of the resolution advantage of the A7R.

Distortion is typical 1.2% barrel.

Lateral CA is noticeable in the corners, but is not severe.

Flare resistance: Haven’t checked.

Measured Focal length is 37mm at 1:35 magnification

Pros and Cons

Effective Resolution

The colors are selected based on overall MP, don’t compare the colors between systems. So relative to max sensor resolution this doesn’t do as well as the lens does on the A7 relative to its (lower) sensor resolution, but it still resolves more detail on the A7R then it does on the A7.s

Aperture Weighted Center Partway Corner
f/2
20.7 MP
25.3 MP
15.1 MP
18.8 MP
f/2.8
27 MP
34.3 MP
19.3 MP
21.1 MP
f/8
28.3 MP
31.3 MP
25.6 MP
24.6 MP

Bottom Line

Great lens, holds up well on the A7R.

I will keep an eye on the chart to make sure it is up to the task. If not it might be losing a bit out of the center, which isn’t so big of a deal, we know the lens is already good there, showing it is 4500 vs 4900 LW/PH might not be too meaningful.

Consider donating, it is about $50 a lens to rent.





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