Amongst my 5-6 50mm (ish) lenses I own are my Carl Zeiss 50mm f1.7 Planar T* and the Canon FL 55mm f1.2.
The Zeiss has a stellar MTF rating of 4.6 and this gives the impresion that it should be among the sharpest 50mm (ish) lenses ever made and that therefore it should easily beat the older Canon for sharpness.
The thing is I had never found the results from my Zeiss justified such a high MTF rating and I got consistantly better results from the Canon, so eventually I got to wondering which one was best...
Today I had some time on my hands so I decided to compare one against the other at typical apertures I like to use, in this case f2.8 and f5.6.
I was supprised to find that the Canon was indeed the sharper lens at both apertures, and had smoother bokeh at both apertures too.
I dont recall the FL 55mm f1.2 ever being tested for an MTF rating but going by the results of my comparison its at least worthy of an 4.6 rating too, if not more.
The subject was the back of an old fridge in my back garden approximately 8' 6" away from the camera, which was mounted on a tripod near the back door in my kitchen.
To ensure the focus was spot on with each lens I drew a letter A on the back of fridge with a fine permanent marker and focused on that.
The comparison pics were all taken from the same spot, which obviously gave the FL a slight focal length advantage so I took crops from the comparsion images reduced the FL crops to the same size as the CZ crops...Even then the FL images are still sharper as very fine text on a lable can be easily read in the FL crops but not so easily in the Zeiss crops.
Here are the crops and just for fun see if you can guess which is which and at what aperture they were taken, without cheating and looking at the image names:

But surely reducing the size of the FL crops makes them appear sharper?

Thanks for the testing nonetheless Alf.

thrice wrote:
But surely reducing the size of the FL crops makes them appear sharper?

Thanks for the testing nonetheless Alf.

Not really...By reducing the size you are throwing away detail. The FL crops actually look sharper at their original size, which incedentaly was only 11 pixels wider than the Zeiss crops!

Keep in mind that the 4.6 rating, and the way it is arrived at, is controversial but it does take into account corner performance. Did you happen to compare these two lenses in the corners?

I once owned the CY 50 1.4 and it was the worst performing 50 I had ever used. Must have had a bad copy, though it was in mint condition.

The last image looks the best from a contrast/sharpness/color standpoint to me but it does appear to be suffering from some magenta ca or something. My guess would be that was taken at 5.6 by the Zeiss?

Thats colour noise due to underexposure I'm afraid. I tried to ensure the exposures were the same but this was'nt possible due to changing light conditions.

Alf Beharie wrote:
Thats colour noise due to underexposure I'm afraid. I tried to ensure the exposures were the same but this was'nt possible due to changing light conditions.

Exposure differences and light conditions would definitely have a bearing on apparent sharpness and legibility, even after post corrections.

Both the Contax/Zeiss and the Canon lenses you tested are old designs. Making inferences as to today's relative performance of Canon and Zeiss lenses based on how old designs perform on today's cameras is hardly scientifically conclusive. It would be like arguing that today's Volwagens are bad because a Beetle emits a lot of CO².

philber wrote:

Both the Contax/Zeiss and the Canon lenses you tested are old designs. Making inferences as to today's relative performance of Canon and Zeiss lenses based on how old designs perform on today's cameras is hardly scientifically conclusive. It would be like arguing that today's Volwagens are bad because a Beetle emits a lot of CO².

No, it would be like arguing about the qualities of the 50/1.7 and the Canon 55/1.2, which is what the poster is doing. I don't think the poster made any comments about modern lenses, Canon or Zeiss, or even any other lenses but the 2 compared.

philber wrote:

Both the Contax/Zeiss and the Canon lenses you tested are old designs. Making inferences as to today's relative performance of Canon and Zeiss lenses based on how old designs perform on today's cameras is hardly scientifically conclusive. It would be like arguing that today's Volwagens are bad because a Beetle emits a lot of CO².

I'm curious as to examples you might have in mind of current 50's that are markedly different than older 50's. Beyond the expensive and rare most recent Leica R 50 1.4 and perhaps some super fast, normal lenses, a lot of current 50's do share the same basic optical design with lenses from twenty years ago I believe. You do have a point about making scientific conclusions, particularly when the sample is 1!

Tariq Gibran wrote:
philber wrote:

Both the Contax/Zeiss and the Canon lenses you tested are old designs. Making inferences as to today's relative performance of Canon and Zeiss lenses based on how old designs perform on today's cameras is hardly scientifically conclusive. It would be like arguing that today's Volwagens are bad because a Beetle emits a lot of CO².

I'm curious as to examples you might have in mind of current 50's that are markedly different than older 50's. Beyond the expensive and rare most recent Leica R 50 1.4 and perhaps some super fast, normal lenses, a lot of current 50's do share the same basic optical design with lenses from twenty years ago I believe. You do have a point about making scientific conclusions, particularly when the sample is 1!

You mean 2...one at f2.8 and one at f5.6 for each lens.

I have owned the Contax 50/1.7 for a short while and never understood all the hype about it. The 55/1.2 was one of Canon's good lenses, and I actually believe many of the old Canon FD lenses were better than the modern EF ones.

Anyhow, from your posted examples, I guess that the Zeiss images are 1st and 3rd, they have the unmistakable bluish Contax cast while Canon images show the usual warm balance. Even in the small crops I see the higher micro contrast in the Zeiss. I think you deliberately changed the file names, but obviously files no. 1 and 3 are taken with the same lens as are 2 and 4.

edwardkaraa wrote:
I have owned the Contax 50/1.7 for a short while and never understood all the hype about it.

+1

Alf Beharie wrote:
Tariq Gibran wrote:
philber wrote:

Both the Contax/Zeiss and the Canon lenses you tested are old designs. Making inferences as to today's relative performance of Canon and Zeiss lenses based on how old designs perform on today's cameras is hardly scientifically conclusive. It would be like arguing that today's Volwagens are bad because a Beetle emits a lot of CO².

I'm curious as to examples you might have in mind of current 50's that are markedly different than older 50's. Beyond the expensive and rare most recent Leica R 50 1.4 and perhaps some super fast, normal lenses, a lot of current 50's do share the same basic optical design with lenses from twenty years ago I believe. You do have a point about making scientific conclusions, particularly when the sample is 1!

You mean 2...one at f2.8 and one at f5.6 for each lens.

I was referring to one sample of his CY 50 1.7. Unless he tested a number of samples and found they all behaved the same, his lens could simply be an anomaly. Perhaps like the 50 1.4 CY I owned.

Interestingly, regarding design, the most current Z series 50 1.4 shares the exact same optical design with the older CY 50 1.4 AND this CY 50 1.7! So, that basic design goes back to at least 1975. Even before that, you will find that many normal lenses shared this basic 7 element design, though there were exceptions:

edwardkaraa wrote:
The 55/1.2 was one of Canon's good lenses, and I actually believe many of the old Canon FD lenses were better than the modern EF ones.


I agree. One of the best normal lenses I ever owned was a Canon 50 1.4 SSC. Sometime after the introduction of "New" Fd's, things started to go down hill.

kidtexas wrote:
philber wrote:

Both the Contax/Zeiss and the Canon lenses you tested are old designs. Making inferences as to today's relative performance of Canon and Zeiss lenses based on how old designs perform on today's cameras is hardly scientifically conclusive. It would be like arguing that today's Volwagens are bad because a Beetle emits a lot of CO�.

No, it would be like arguing about the qualities of the 50/1.7 and the Canon 55/1.2, which is what the poster is doing. I don't think the poster made any comments about modern lenses, Canon or Zeiss, or even any other lenses but the 2 compared.

My argument rests on the title of his thread: "dispelling the Zeiss superiority". The title spells out a general theory based on his experience of two specific (and old) lenses.

philber wrote:
kidtexas wrote:
philber wrote:

Both the Contax/Zeiss and the Canon lenses you tested are old designs. Making inferences as to today's relative performance of Canon and Zeiss lenses based on how old designs perform on today's cameras is hardly scientifically conclusive. It would be like arguing that today's Volwagens are bad because a Beetle emits a lot of CO�.

No, it would be like arguing about the qualities of the 50/1.7 and the Canon 55/1.2, which is what the poster is doing. I don't think the poster made any comments about modern lenses, Canon or Zeiss, or even any other lenses but the 2 compared.

My argument rests on the title of his thread: "dispelling the Zeiss superiority". The title spells out a general theory based on his experience of two specific (and old) lenses.


Agreed. Dispelling the Zeiss superiority myth by comparing a budget lens intended for amateurs (and possibly the cheapest Zeiss lens ever made) to what was considered at the time a pro lens from Canon

Tariq Gibran wrote:
Interestingly, regarding design, the most current Z series 50 1.4 shares the exact same optical design with the older CY 50 1.4 AND this CY 50 1.7!


You lost me with the word "exact". While these 3 Zeiss lenses share a similar design, they are not exact. The 50/1.7 being the most "different" of the 3, not to mention the cheapest. The ZF50 is clearly descended from the c/y 50, but they are not exact. The ZF is an update of the older design, and the differences in the MTF's confirm that. There are almost certainly differences in glass formula as well as small tweaks to the geometry of the elements. That said, I think that Zeiss should have put more effort in the the ZF 50/1.4 to more effectively distinguish it. While the c/y 50/1.4 might have been a category leading lens 25 years ago, the rest of the industry is closer today. I think there are a lot of people that would have preferred to see a step-out new design for the ZF50/1.4 rather than a minor updating tweak to the old c/y design.

Finally, on this comparison, I'm not so sure that a top-of-the line, exotic, very expensive (in its day) Canon lens is the likely competitor for this entry-level, cut-rate, corner-cutting, inexpensive, basic Zeiss 50/1.7 lens. I would have expect the Canon to be better. Hell, it cost a lot more. Further, these one number average weighted scores for lenses are highly suspect and can be misleading depending on how the lenses are actually used. Quite clearly, the Canon could be sharper in the area of the frame you examined while garnering a lower overall score when the rest of the frame is considered.

The crops are all from the centre of frame and from RAW files therefore about as sharp as it gets without adding sharpening in post processing.

Lotusm50 wrote:
Tariq Gibran wrote:
Interestingly, regarding design, the most current Z series 50 1.4 shares the exact same optical design with the older CY 50 1.4 AND this CY 50 1.7!


You lost me with the word "exact". While these 3 Zeiss lenses share a similar design, they are not exact. The 50/1.7 being the most "different" of the 3, not to mention the cheapest. The ZF50 is clearly descended from the c/y 50, but they are not exact. The ZF is an update of the older design, and the differences in the MTF's confirm that. There are almost certainly differences in glass formula as well as small tweaks to the geometry of the elements. That said, I think that Zeiss should have put more effort in the the ZF 50/1.4 to more effectively distinguish it. While the c/y 50/1.4 might have been a category leading lens 25 years ago, the rest of the industry is closer today. I think there are a lot of people that would have preferred to see a step-out new design for the ZF50/1.4 rather than a minor updating tweak to the old c/y design.

Finally, on this comparison, I'm not so sure that a top-of-the line, exotic, very expensive (in its day) Canon lens is the likely competitor for this entry-level, cut-rate, corner-cutting, inexpensive, basic Zeiss 50/1.7 lens. I would have expect the Canon to be better. Hell, it cost a lot more. Further, these one number average weighted scores for lenses are highly suspect and can be misleading depending on how the lenses are actually used. Quite clearly, the Canon could be sharper in the area of the frame you examined while garnering a lower overall score when the rest of the frame is considered.



But the more expensive Zeiss 50mm f1.4 Planar T* has a lower MTF rating than the "cheap" 50mm f1.7 Planar T*.
According to this MTF list of lenses with MTF ratings of 4.1 or higher the Zeiss 50mm f1.7 Planar is one of the sharpest 50mm lens in the whole list, equal only to the Leica M Summicron-M 50mm f2.0, Pentax AF SMC-F 50mm f2.8 macro and the Pentax AF SMC-F 50mm f1.4.

Grade: 4.8 35mm/AF Canon EF 200/1,8L USM
Grade: 4.7 35mm/AF Contax G Planar 45/2,0
Grade: 4.6 35mm/MF Tokina AT-X 90/2,5 macro
Grade: 4.6 35mm/MF Pentax SMC-A 85/1,4
Grade: 4.6 35mm/MF LeicaR Elmarit-R 90/2,8 discontinued
Grade: 4.6 35mm/MF LeicaM Summicron-M 50/2,0
Grade: 4.6 35mm/MF Contax Planar T* 85/1,4
Grade: 4.6 35mm/MF Contax Planar T* 50/1,7
Grade: 4.6 35mm/AF Pentax SMC-F 50/2,8 macro
Grade: 4.6 35mm/AF Pentax SMC-F 50/1,4
Grade: 4.6 35mm/AF Canon EF 85/1,2L USM
Grade: 4.5 35mm/MF LeicaR Summicron-R 50/2
Grade: 4.5 35mm/MF LeicaR Apo-Macro-Elmarit-R 100/2,8
Grade: 4.5 35mm/MF LeicaM Summilux-M 75/1,4
Grade: 4.5 35mm/MF LeicaM Elmarit-M 90/2,8
Grade: 4.5 35mm/MF Konica M-Hexanon 50/f2
Grade: 4.5 35mm/MF Contax Planar T* 50/1,4
Grade: 4.5 35mm/AF Minolta AF 50/2,8 Macro1:1
Grade: 4.5 35mm/AF Minolta AF 100/2,8 Macro 1:1
Grade: 4.5 35mm/AF Canon EF 135/2L USM
Grade: 4.4 35mm/MF Nikkor Micro 55/2,8
Grade: 4.4 35mm/MF Nikkor 85/1,4
Grade: 4.4 35mm/MF Nikkor 105/1,8
Grade: 4.4 35mm/MF LeicaR Apo-Telyt-R 280/2,8
Grade: 4.4 35mm/MF LeicaR Apo-Telyt-R 180/3,4
Grade: 4.4 35mm/MF Canon FD 50/1,8
Grade: 4.4 35mm/AF Pentax SMC-F 50/1,7
Grade: 4.4 35mm/AF Nikkor AF 50/1,8
Grade: 4.4 35mm/AF Minolta AF 50/1,4
Grade: 4.4 35mm/AF Minolta AF 100/2,0
Grade: 4.4 35mm/AF Contax G Sonnar 90/2,8
Grade: 4.4 35mm/AF Canon EF 50/2,5 Macro
Grade: 4.4 35mm/AF Canon EF 50/1,4 USM
Grade: 4.4 35mm/AF Canon EF 400/2,8L II
Grade: 4.4 35mm/AF Canon EF 400/2,8 L IS USM
Grade: 4.3 35mm/MF Yashica ML 50/1,4
Grade: 4.3 35mm/MF LeicaR Summilux-R 50/1,4
Grade: 4.3 35mm/MF LeicaM Summicron-M 90/2,0
Grade: 4.3 35mm/MF Contax Distagon T* 28/2,8
Grade: 4.3 35mm/AF Tamron AF SP 90/2,8 Macro
Grade: 4.3 35mm/AF Pentax SMC-F 100/2,8 macro
Grade: 4.3 35mm/AF Nikkor AF DC 135/2D
Grade: 4.3 35mm/AF Contax G Biogon 21/2,8
Grade: 4.3 35mm/AF Canon EF 300/4L USM
Grade: 4.2 35mm/MF Tamron SP 90/2,5 macro
Grade: 4.2 35mm/MF Pentax SMC-A Macro 200/4ED
Grade: 4.2 35mm/MF Pentax SMC-A 135/1,8
Grade: 4.2 35mm/MF Olympus 90/2 macro
Grade: 4.2 35mm/MF Nikkor Noct 58/1,2
Grade: 4.2 35mm/MF Nikkor 85/2,0
Grade: 4.2 35mm/MF Nikkor 50/1,2
Grade: 4.2 35mm/MF Nikkor 105/2,5
Grade: 4.2 35mm/MF LeicaR Vario-Elmar 80-200/4
Grade: 4.2 35mm/MF LeicaM Tele-Elmar-M 135/4,0
Grade: 4.2 35mm/MF LeicaM Summilux-M 50/1,4
Grade: 4.2 35mm/MF LeicaM Noctilux-M 50/1,0
Grade: 4.2 35mm/MF Konica M-Hexanon 28/f2.8
Grade: 4.2 35mm/AF Sigma AF 90/2,8 Makro
Grade: 4.2 35mm/AF Sigma AF 50/2,8 EX Macro
Grade: 4.2 35mm/AF Pentax SMC-FA 50/1,4
Grade: 4.2 35mm/AF Nikkor AF-I 300/2,8 IF-ED
Grade: 4.2 35mm/AF Nikkor AF Micro 60/2,8D
Grade: 4.2 35mm/AF Nikkor AF 85/1,8
Grade: 4.2 35mm/AF Nikkor AF 50/1,4D
Grade: 4.2 35mm/AF Contax G Biogon 28/2,8
Grade: 4.2 35mm/AF Canon EF 80-200/2,8 L
Grade: 4.2 35mm/AF Canon EF 50/1,8 II
Grade: 4.2 35mm/AF Canon EF 100/2 USM
Grade: 4.1 35mm/MF Nikkor Micro 105/2,8
Grade: 4.1 35mm/MF Nikkor F 28/2,8
Grade: 4.1 35mm/MF Nikkor 50/1,8 (E Series)
Grade: 4.1 35mm/MF Nikkor 400/2,8 IF-ED
Grade: 4.1 35mm/MF Nikkor 180/2,8 ED
Grade: 4.1 35mm/MF LeicaM Summicron-M 35/2,0
Grade: 4.1 35mm/MF LeicaM Elmarit-M 28/2,8
Grade: 4.1 35mm/MF LeicaM Elmarit-M 135/2,8
Grade: 4.1 35mm/MF Contax Sonnar T* 85/2,8
Grade: 4.1 35mm/MF Contax Sonnar T* 135/2,8
Grade: 4.1 35mm/AF Sigma AF 105/2,8 EX Macro
Grade: 4.1 35mm/AF Nikkor AF-S 80-200/2,8 IF-ED
Grade: 4.1 35mm/AF Minolta AF 28/2,0
Grade: 4.1 35mm/AF Minolta AF 200/2,8 APO-G
Grade: 4.1 35mm/AF Contax G Planar 35/2,0
Grade: 4.1 35mm/AF Canon EF 85/1,8 USM
Grade: 4.1 35mm/AF Canon EF 70-200/4 L
Grade: 4.1 35mm/AF Canon EF 70-200/2,8 L USM
Grade: 4.1 35mm/AF Canon EF 200/2,8L II

I would be supprised to find my FL 55mm f1.2 has a higher rating than 4.6 but its certainly possible going by my comparison pics.

Comparing lens is a thankless task. True, your sample of each lens may say one thing, and another photographers samples of theirs may tell a completely different story.

Case in point: There seems to be no argument that the Leica Elmarit 28/2.8-R is perhaps the finest 28mm SLR lens available. I compared one known to be in tip-top condition, the latest design, to my Contax 28/2.0 Distagon, which itself had been recently serviced by Zeiss. In my tests, my Contax was equal to and in some tests, beat the performance of the Leica. (All variables were looked at, adapter thichness, tests were focus bracketed, etc., etc.)

The Canon 200 f/1.8 is on there twice? Where did these come from, out of curiosity?
Alf Beharie wrote:
Grade: 4.8 35mm/AF Canon EF 200/1,8L USM
....
Grade: 4.8 35mm/AF Canon EF 200/1,8L USM

edwardkaraa wrote:
I have owned the Contax 50/1.7 for a short while and never understood all the hype about it.

-1

Contax Planar T* 85/1,4 is on there 3x and many others are doubled up - any reason?

These looks like the Photodo ratings.

One copy of a cheaper Zeiss lens against one copy of a Canon lens does not prove anything to me about brand superiority. I have an FL 55/1.2 converted to EF mount. It is a great lens, no doubt. But it does not make me want to try out more old Canon lenses nor ignore all the new Zeiss lenses coming out. How old are those Photodo ratings anyways? How many magnificant lenses have been made since that list was produced?

gasrocks wrote:
One copy of a cheaper Zeiss lens against one copy of a Canon lens does not prove anything to me about brand superiority. I have an FL 55/1.2 converted to EF mount. It is a great lens, no doubt. But it does not make me want to try out more old Canon lenses nor ignore all the new Zeiss lenses coming out. How old are those Photodo ratings anyways? How many magnificant lenses have been made since that list was produced?


+ 10. My thoughts exactly. Well said.