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Monday, November 25, 2013

Sony A7r with Carl Zeiss 35mm f2 Biogon ZM Test Sample Images - Some Vignetting and Corner Smear

Looking good...and I'm not talking about the cheese cake here

This has been the number one lens I have been waiting to test the A7r on. Before buying the camera and also while I was waiting for my pre-order to arrive, I have been looking at many sites on the Internet regarding how different range finder lens perform on the A7r. A few quite famous sites said that anything 35mm and longer should work great, and one even said that the Carl Zeiss 35mm f2 Biogon ZM was one of their favourite lens to use on the A7 and A7r, so naturally I was eager to get to try it myself considering how much I enjoyed using the lens on the Canon EOS M.

Before we start I have got to first off apologize for the quality of the images. I just have not had the chance to go shoot anything interesting, but from the shots that I got there are some information I would like to share, so let's get started.

How did the lens perform? Well I seem to be getting some interesting and confusing results for some reason. I have not found any color fringing in any of the photos I have taken yet (and I have taken quite a number), so hopefully that continues. There is definitely vignetting however,


Sony A7r f2.8 ISO 250

 There is definitely vignetting BUT it seems to really be most noticeable when shooting under low light conditions like indoors. It can be quite significant when using wide-open apertures like f2 or f2.8 but as you get to f5.6 then it's not really that bad and from f8 onwards it is only quite slight. For me the problem of vignetting is something I can live with, it can be corrected without too much hassle in post and to be honest most of the time when I am using wide apertures the edges of those particular shots are not in focus and some vignetting does not really affect it.

Corner Smear

Now this is where I am getting some confusing results. Vignetting I can live with but having corner smear is something that just does not look good and can not really be fixed in post. For some reason in a few of my shots I seem to be getting some corner smear, or at least the edges of the photos are really blurry and it's not dependent on apertures either.

Sony A7r f4 showing corner smear

From the shot above the center, top center and bottom center of the photos are fine, with the center being really really sharp.

100% Crop Left Side
100% Crop Right Side

As you can see from the two 100% crops above however, the left and right side of the photo is really blurry.

Sony A7r f11 showing corner smear

Again this time the photo was taken at f11, and again the smearing occurs on the left and right side of the photo.

100% Crop Left Side

100% Crop Right Side
The smearing is not nearly as bad as in the first photos but it is still there. I am not sure what is causing it but I do not think it is the adapter because usually if the tolerance of the adapter is off the defect in the photo will not be so symmetrical. I mean if there are vignetting or corner smearing the pattern would not be symmetrical on both sides, one side would be different to the other. It does not seem to be the shooting conditions either as you can see from the photo below.

There does not seem to be any corner smearing on this one

The photo above was taken within a few minutes of the two other shots that have corner smearing but it does not appear to have any corner smearing at all.

100% Crop

100% Crop

I have got to say that the previous two photos were the only ones that I experienced corner smearing and I am still not sure what caused it. With all the other photos I took however, I did not find any corner smearing at all.

Sony A7r f5.6
The shot above, for example, is perfectly sharp across the frame, which is much more representative of most of the photographs that I got using this lens.

100% Crop Perfectly Sharp

Conclusion...for now.

So what do I think? Well so far shooting with this lens is a joy. Apart from the two shots that I found corner smearing in all the others were fine and very very sharp especially in the center. The thing that might be even more important however is how much fun I had using the lens, the size, weight and handling of the lens just made using it a great experience.

Since I have only been using it for a few days though it will probably take more time before I can come up with a definite conclusion of how much I love (or not) this lens. So I will keep you posted with new updates and hopefully better shots than these as I get to use the lens more.


  1. Corner smearing is dependent on focus distance and worse at infinity, so in your shots that are focused closer the smearing i not problematic I guess.

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