Zeiss APO Sonnar 135mm f/2 (ZF.2) Review
Looking at the MTF chart above we can notice one interesting lens behavior. While at f/2 both Sagital and Tangential lines are keeping close together (indicating low CA), at f/4 they gets apart toward the edges.
On the other hand, considering that those charts are result of real life measuring, it is amazing to see how even contrast and resolution are kept across the frame straight from f/2. By stopping lens down to f/4 we can notice increase of resolution while contrast shows only light boost. Considering that at R10 lens achieve over 95% MTF in almost entire projection and that even at R40 it never really drops bellow 60%, we should be ready to witness breathtaking sharpness in a real life. Razor sharp can’t look much better than this according to this results.
Vignetting and Distortion:
At wide open aperture lens shows some light fall off toward edges (approx. 2/3rd of EV) but good thing is that vignetting is very linear so you should not notice transition areas. Stopped down to f/2.8 drastically improves performance and at f/4 vignetting becomes non issue. Distortion is hardly noticeable which is to be expected from high quality 135mm lens.
Let’s take a look how those data manifests visually.
(In this review I used Nikon D800E to test the lens, which is probably not the best option because of possible shutter shake issues, but I shot in LCD – mirror up mode with shutter delay. I will also make shoot out with Sony A7 camera that has EFC, just to be sure.)
This is test chart and red squares indicate respective zones of 100% crops that will follow.
Here are 100% crops of respective zones at aperture stops from left to right – f/2, f/2.8, f/4, f/5.6
and from f/8 to f/22
By clicking on those images you should be able to open them to original size, where each presented crop (zone) is shown at pixel level of 800x600px. If you prefer to look at original size files, you should find them all on my Flickr Service Album – Nikon D800E + Zeiss APO Sonnar 135mm f/2 ZF.2
Visually judging contrast and resolution of this lens is unique experience IMHO. Just as MTF results suggest, lens is sharp from f/2 up to the extreme corners. Both resolution and contrast are probably highest that I have ever seen in my tests. Stopping lens down improves sharpness further up to f/5.6 (at pixel level), but this is one of the rare lenses that I would probably feel confident to use wide open even for the landscape shots (if I ever experience the need to do so). Simply outstanding results.
Diffraction starts to affect resolution (start to be notable at a pixel level) from f/8 on and considering how clean and crisp image is at f/5.6, I would consider this f-stop to be optimal for the lens (unless you need extreme DOF).
Here are few comparisons between apertures for your consideration, but don’t forget that you are looking at basically unprocessed RAW files (just standard processing in LR 5.7 without applied lens profiles of course) at pixel level.
f/2 vs f/5.6 – sharpness zone
And f/8 vs f/22 – Diffraction zone
While f/5.6 might look much better than f/2 and f/22 might look unusable, I would say that this lens is perfectly fine at all apertures varying from insanely good to great or very good. I would like to know if there is theoretical (or real life tested) maximum resolution for this lens, because I believe that it can easily out resolve recently announced 50mpx and up sensors.
Let’s make it simple – this is sharpest lens that I have tested in person so far (I still have to find time for Otus line and Sigma Art).
However, for the price balancing at 2000 USD edge, it is to be expected, considering Zeiss experience and knowledge, but…
On the other side of our gray (formerly known as blue) planet, more precisely in South Korea, company that I first heard about related to lens business just few years ago, originally named Samyang (but also known under many other private label brands – Bower, Rokinon e.g.), planted on the market few great lenses especially considering price/performance ratio.
I remember than when I bought my first Samyang lens – 14mm f/2.8 and I went out with my photo friends, they looked at me with compassion as to someone who can’t afford quality optics. One of them wasn’t able to remember the producer name for the whole weekend, calling it all possible variations such as Samtex, Pingpong etc. so it ended with a nice and simple nick – Sam.
When they saw results however, many of them went with Sam and are happily shooting all around.
Samyang lenses are not sexy, they don’t have 3D pop neither 4D corn, built quality is functional at best and QC in Korean probably means Quantifying capitalization, but who ever was responsible for development of already mentioned 14mm/2.8, 35mm/1.4, 85mm f/1.4 or APS-C line (12/2, 16/2.8, 8/2.8 fisheye) is or are very, very talented optician.
Why so much writing about Samyang?
First I really think they deserve more publicity and second, they just introduced new 135mm f/2 on the market and first shy reviews were almost all raving.
Their (theoretical) MTF looks quite amazing and surprisingly similar to Zeiss but it is measured at R10 and R30 while Zeiss is at R10 and R20, but most importantly, Zeiss results (above) are real life tests, while Samyang is theoretical.
(Theoretical MTF basically mean, that as many other producers, Samyang shows the result that would apply to ideal conditions – vacuum, 100% even illumination, perfectly crafted and assembled lens, honest politicians, etc. In comparison to the real life test, theoretical (or computerized) is similar to what I expected my life to be when I was 6 y.o. and what it is in reality today. Or there about…)
Well dear Zeiss APO Sonnar (every word in its lens name sounds pricey don’t you think :-)), it seems that you won’t have easy life…
Seriously though, I had to buy Samyang lens from UK in order to get it for this review, but it cost me 500 USD, so almost 4 time less than Zeiss price point.
Challenge was born, but I decided to include also one of my favorite 135mm lenses in the contest – Oldie but Goldie Nikkor 135mm f/2 AF DC.
All tests were performed using Nikon D800E (Studio tripod, laser aligning, professional target, even permanent illumination etc.)
Following comparison zone crops are related to the same zones listed above, but I am posting it here once more, so that you don’t have to scroll up and down.
To use our slider comparison tool, click and hold with cursor on the circle with arrows in the middle of the image and move it left or right to reveal image bellow. Color bars on the top with lens name and tested aperture, as well with zones listed from left to right and from top to bottom, should help you in orientation.
1. Zeiss APO Sonnar 135mm f/2 ZF.2 vs Samyang 135mm f/2 ED UMC ZF.2
In this Test chart comparison, shot from a close distance of about 1.5m, Zeiss is winner at all apertures. But in real life tests at medium and long distances, Samyang often surpassed Zeiss in center sharpness. Different focus plane optimization?
Beside differences in sharpness, you might notice different rendering of white/gray color. While Zeiss is neutral, Samyang has quite strong shift toward warm tones. This proved to be true in a real life as you will see in the following parts of the review – difference is quite significant in that regard.
Finally, while aligning test chart I noticed that Samyang has somewhat wider FOV than Zeiss and Nikkor.
If you want to see original size files, they are available on my Flickr Service Albums:
But don’t be fooled, Samyang still performs well wide open when compared with older Nikkor e.g.
And I am not talking about lack of CA, we will come to this later…
2. Zeiss APO Sonnar 135mm f/2 ZF.2 vs Nikkor 135mm f/2 AF DC (DC set to neutral)
You can find original size Nikkor files by clicking here.
There is no doubt that Zeiss APO Sonnar in this studio test is a clear winner. However even if I would stop review here, I can still see many reasons to go with other two lenses, because their performance is still very good. I am not worried about Samyang center sharpness result here, because in a real life situations it often surpassed Zeiss in the center, but extreme corners could be a tad better. On the other hand, if you look carefully to those crops, you might notice a very tinny bit of persisting purple fringing in Zeiss APO Sonnar samples, while Samyang is absolutely CA free in my eyes, despite lacking fancy APO sign.
Nikkor despite its age is still capable of excellent results, beside very strong purple fringing wide open. Stopped down to just f/2.8 cures most of it and Nikkors power is hidden in DC feature, allowing it to create very smooth foreground/background blurriness and dreamy softness on the subject at the same time.
But yeah… Zeiss wins this one!
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