Jesse,
I like to response to your techical questions regarding to the data that were presented.
1. Yes it is alot easier to design a lens that is F2 than F1.2. This is one of the reason why I believe Leica choose not to build anything below an F1.4 in the Reflex system. I came to respect the engineer of Zeiss glass and the challenge they have achieved. What amazed me about these lens tests is that we are not testing against Sigma, Tamaron or any other lens that we all considered inferior lens but good lens is that great lens being able to out performed another great lens. I do like the Leica 90mm F2.0 but if I have to choose one I will use the Zeiss 85mm F1.2 for many advantage as a portrait lens.
2. Both Zeiss 85mm F1.2 and Leica 90mm F2.0 have Aspherical element. Zeiss choose not to mentioned it on the lens itself.
3. Though Zeiss does not tell you that the glass they used were UD glass but I am sure they have used high quality glass which I do not know thus cannot imply specifically. However, if you look at the glass of one of these thing it is crystal clear and not like the Canon 85mm f1.2L. Also the clarity of the images is another aspect from this lens that you observed. Furthermore, when I tested these lens awhile back I also noticed that the black letter stay very dark for the Zeiss while the Leica 90mm F2.0 show a slight tin of greenish shade. Thus, for me the Zeiss look to have higher Dmax value from observation; this may be due to high contrast or CA attenuation which it is hard to separate here. Therefore the question of CA comes in and I did not get the opportunity to test the CA under server condition. I wish I did. The Zeiss does show more CA when wide open than versus stop down. If you look at the data that David Klepacki posted on my thread you will see the purple fringing goes away at F2.0 for the Zeiss. Though I have not see one of these lens in the 85mm focal lenthg that has no CA. The one thing that the Zeiss has is floating element while the Leica does not.
Thus, it is more advantage for the Zeiss lens in close up while the Leica will show optical aberration such as pincushion distortion that is rather high for the Leica when you go close up. Despite that it does not have floating element but from my experiences the 10 feet away does not show the pincushion distortion for the Leica lens thus at 10 feet at least we know that the lens can perform without some of the features of optical aberration. Also for other lens such as the Canon 85mm F1.8 is also very sharp at 10 feet away as well and this lens also has no floating element. So my judgement of the lens performance at this testing is reasonable but could be improved for the peak performance of the Leica lens.
In conclusion, every test has its strength and weakness but every test allow us to see the dynamic of lens optimization under certain condition thus translate to its potential application. Most of our testing are not fair when comparing two different lens that were engineer for different reasons and some of the lens were compromised due to the challenge of optical correction and expenses. Yes it gives the Leica advantage to design F2 over F1.2 due to easier to control optical aberration. To me Canon and Leica has found ways to build great lens in the 85mm F1.2L and Apo-Summicron-R 90mm F2.0. For me I have come to admire and respect the unique of Zeiss achievements in this anniversary.
Lesong,
What the data will impress you is that it is the center and you know Canon is very well known for center sharpness. What I wanted to test was the strength of Canon and also the likely place where portrait would be used. The data was acquired from the lens that you sent to me. Thanks for the great lens.
You can clearly see the advantages the Zeiss has over the Canon by looking at the color smear on the text at the bottom of the color chart to the left, in the Canon on the f/1.2 shots.
But IMO the actual portrait itself is sharper in th Canon. --c
The CZ is obviously front focused in the samples (look at the woman's knee), remindering me how hard it is to do comparison in real world shooting instead of controlled target shooting.
Edited by Cinstance on Aug 15, 2005 at 09:20 AM GMT
thank you, cincstance, very very much. these are great. the optical qualities of both lenses are really really good. i cannot see a reason to buy the cz over the canon.
Cinstance wrote:
The CZ is obviously front focused in the samples, remindering me how hard it is to do comparison in real world shooting instead of controlled target shooting.
yeah, i cannot see a reason to give up the af of the canon.
The samples are not from me, but a Japanese site. Glad your guys find it helpful
Son, glad you like the lens and thanks for sharing the data. Controlled tests show the maximum potential of the lens, and it's the job of the photographer to bring out the potential.
Lesong, yes I was going to say that the potential of the lens is the challenge for the photographer to take advantage of it. We have to think the dynamics aspect of photography and are we capable to take advantage of the optical performance of the lens to bring it to fruition. We must asked ourselves that very question. I found one of my strength is in manual focusing and I hope my ability can take advantage of this lens in my next step.
Real life samples will never show the difference between them. If they do, the diff is contributed by some other factors than the optical performance.
This is a highly controlled test. And I have been calling them "Virtual" performance because one would never achieve the full potential entitlement of the 85mm lenses due to the extreme difficulty in focusing with wide apertures. In real life situations, Canon will very likely to outperform CZ 85/1.2 thanks to its Faster focus and easier exposure.
From the test shots provided by Cinstance, it appears that the L lens has the edge. Further, in real world shooting at such wide apertures, the AF ability of the Canon lens would likely trump much of the purported sharpness advantages offered by the Zeiss, which incidentally (of course) costs 2-3 times more.
My vote goes to the Canon on a performance/price basis, not to mention AF.
JJ
PS. I had on of these a very long time ago. It's great wide open but the Leitz 80/1.4 absolutely killed it once stopped down to f5.6/8. I kept the leitz...
Pham Minh Son wrote:
tchotchke,
There is one way to adapt it and I am planing to do it when I get the chance. The only way to do it is to shave off at least 2mm on the rear mount and put in a new EF bayonet and you will get to infinity. But I also need to know if it will interfer with the mirror. I might also need to modify the mirror as well.
-Son
Ignoring the TC affects of the FD-EOS adapter sold by Canon, couldnt you mount it on a non optical adapter (without modifying the lens or body) and just measure the lens within its available range? So if the scale goes to 10 or 12 feet or something and then to infinity, you would lose infinity + but should still be able to focus to 10 feet or so. Since the tests arent at infinity, I don't think anyone would balk at it.
The maximum aperture size of 1.4 on Leica's reflex system is due to the diameter of the lens mount rather than any issue intrinsic to lens design. Of course in general the larger the aperture the more difficult it is to design a lens, but Leica has shown their capability in designing super fast lenses with the 50/1.0 Noctilux-M. The performance of that lens is arguably still unsurpassed.
In general I don't think this was the right setup to test the Leica 90/2.0R. That lens has a telecentric design and was optimized for infinity focus rather than 10ft. My guess is if you tested your three lenses at infinity the results could differ.
