Introduction:
Wide and super wide angle lens has been well characterized from pass studies. However, the portrait lens are also very popular for photographer but little information is known about these lens. Recently I have the opportunity to characterized some of the most popular portrait lens in the market on a full frame Canon digital SLR camera.
Material & Method:
1) Lens: Carl Zeiss Planar T* 85mm F1.2, Canon EF 85mm F1.2, Leica Apo-Summicron-R 90mm F2.0
2) Manual focusing bracketed for compensation of adapter thickness and focusing tolerance
3) 1/2 inche black gator foam core mount the test target and the distance is approximately 10 feet.
4) Canon 1Ds Mark II with Contax 45 degree split focusing screen & Canon Angle Finder C
5) Quantum T2 Flash and located high near to the ceiling to bring out the high contrast of the lens.
6) Gitzo Tripod & Markins Q-Ball M10
7) ISO 100 & Manual metering
8) Mirror Lock Up and waited for 5 second prior to releasing the shutter
9) Zero sharpen with Raw Shooter
10) Imatest Software for computation & graph
Results & Interpretation:
These data are relative number and not absolute value even though the results are shown numberical value. The value of the lens are all relevant to each other based on the condition of the testing. This is not a number where you can simply put it down on the spread sheet and interpret them as the absolute number. The results values reported here are in cycles/mm. The Zeiss Planar T* yield the highest cycles/mm at all F stops: F1.2 Zeiss is 65 and Canon is 41; F2.0 the Zeiss is 74.9, Canon is 58.4, and the Leica Apo-Summicron-R 90mm F2.0 is 66.4; F5.6 Zeiss is 82.3, Canon is 79.5, and Leica is 71.
Conclusion:
Normally Leica is known to be the sharpest lens at wide open and the slope of increasing resolving power to F5.6 is not as steep as Zeiss and Canon. However, there are few exception where the Zeiss lens are simply extraordinary and render extremely high micro-contrast at wide open f stops and continue to increase at a steep slope at F5.6. The particular Canon EF 85mm F1.2L lens are very sharp at wide open as well but not the same as the Zeiss or Leica here. However, the Canon is a sharper lens at F5.6 than the Leica. At this focal length the Zeiss optics appears to be the best among all three very popular portrait lens at all f stops.
Edited by Pham Minh Son on Aug 10, 2005 at 03:55 PM GMT (Reason: Add extra information to Method section)
Son,
Not sure what all this means, but I suspect it's going to cost me $$$ Seriously though, your dedication to testing these lenses is nothing short of amazing. Thank you for sharing your efforts with us.
Son, wow that is a very detailed and well-documented test. Thank you very much for doing it. However, it is hard for non-optical expert, like myself, to make out the difference charts and to understand except for the conclusion part, which is kind of ambiguos still. If somebody puts a gun at your head and ask you to rank them, you would put the Zeiss on the top, followed by the Canon and Leica. Is this the bottom line I am reading ?
Joshua,
Yes, as you know I have spent alot of time and effort to characterize exotic lens particularly the Leica and more so the Zeiss and the results of these lens is simply blown me away. Yes, the Zeiss Planar T* 85mm F1.2 Anniversary is the most amazing lens I have seen. It is harder to rank the Canon versus the Leica though since the Leica is sharper at wide open F2.0 than the Canon. However, the Canon is a sharper lens at F5.6. This is what we expect from Leica simply sharp wide open and a steady increasing as you stop down the lens up til F5.6 while Zeiss and Canon slope is steeper up to F5.6. If I have to pick the two later this is what I would rank. Zeiss, Canon, Leica in this portrait focal length.
Jia,
Thanks just a little more scientific.
-Son
Edited by Pham Minh Son on Aug 10, 2005 at 04:06 PM GMT
Robert,
I have not get the chance to test the Zuiko 90mm F2.0 but from other experience is that it is not a stellar lens. I also based this information with my own experience since Zuiko lens only made a few that has rare earth element for their optics and the 90mm F2.0 and the 180mm F2.0 and based on my testing of the supposed claimed best Zuiko 180mm F2.0 where the Leica was supposed to copy from is not as sharp as the Leica. Here is the results from that studies. https://www.fredmiranda.com/forum/topic2/232595/0#1910952
Thus my own conclusion is that the Zuiko 90mm F2.0 is not going to be a spectacular lens. Sorry to Zuiko fan here.
Thanks for doing all these, Son. Perhaps we need a little workshop to help everyone learn more about what the results mean. As we discussed on the phone, I am very frustrated with the so-called "test reports" and "outrageous" claims with nothing but snapshots and no appropriate "controls". This put more "science" into the field! Like a meeting in my lab, let me say: "We need more data on these, don't you think?"
The optimization of the Planar Formula is from 50mm to 135mm focal length. The Planar focal length extreme end at both spectrum are not as good as the middle one. Thus, the 50mm and 135mm Planar are not as good as those in the inner focal length such as the 55mm F1.2 and 85mm F1.2. The Zeiss 100mm F2.0 is better than the Zeiss 135mm F2.0.
Pham Minh Son wrote:
The optimization of the Planar Formula is from 50mm to 135mm focal length. The Planar focal length extreme end at both spectrum are not as good as the middle one. Thus, the 50mm and 135mm Planar are not as good as those in the inner focal length such as the 55mm F1.2 and 85mm F1.2. The Zeiss 100mm F2.0 is better than the Zeiss 135mm F2.0.
-Son
What do you mean exactly? The 135mm is a Sonnar, not a Planar
Seriously though, your dedication to testing these lenses is nothing short of amazing. Thank you for sharing your efforts with us.
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