Dispelling the Zeiss lens superiority Myth...

[DSG]

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...(The FL crops are 11 pixels wider).
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.
(BTW, these are straight from the camera with no processing and all were underexposed a bit hence the colour noise):

[Nesster]

Applause for the creative test target.

However, your test is invariably biassed by that "A" you drew - after all CAnon is very near "A" in the alphabet, while Zeiss is about as far as you can get. The letter "M" might have avoided this bias. [joking here]

The first and third are the same lens and the second and fourth - I'm using the color cast, though if I peer closely enough the 1/3 seem a bit more legible as well.

The coils to my eye on 4 are the most in focus though - I know you didn't focus on them, but I suppose this would be with the lens closed down a bit.

[trifox]

Well, I have done some comparison is this line:

Contax Planar 1.4/50 and Canon FD 50 f1.2

Canon was sharper -- but the test is NOT FAIR because of this:

aperture stops were different ..

In your case: Canon 55 has longer focal length and also different initial aperture than Contax 1.7

You would have to do a test between:

Canon FD 55 f1.2 and Contax Planar 1.2/55 and make a statement

tf

[Orio]

I think the problem is in the superiority concept - and also in limiting it to sharpness.
About superiority, this is really a vain concept in my opinion. First, no maker makes all perfect lenses - there are always some that are better than others. For instance, Zeiss Oberkochen made the Distagon 21, which is the best 21mm existing, but it also made the Tele-Tessar 300, which is a well below average lens.
Secondly, superiority is inane on a practical point of view: all the best lenses in the lineups of the most reputed brands will let a photographer make a job: Zeiss, Canon, Nikon, Leica, Pentax, Olympus, and maybe other brands - these are all brand that are able to produce professional equipment.

What is more true is that every good manufacturer gives its lenses a character, that is common to all models (while bad manufacturers make lenses that are not omogeneous in the image rendering).
So of course if a person likes the Zeiss type of image better, he will prefer all the Zeiss lenses, but the same happens with Takumar lovers, and Leica lovers...

About sharpness, one should really test at least three different samples of each model in order to be able to say something meaningful. The copy variation factor affects also the best brands - actually, even more than the other brands, because the best brands usually produce the best lenses and the best lenses have a tolerance for build error that is much minor than everyday workhorse lenses.

Then I agree with the comment that comparing two different focal lenghts is problematic. The longer lens always feels sharper. I noticed that myself several times.

Finally: sharpness is not the end of all lens things. There are other important factors to a lens.

[hinnerker]

[mflex-on]

[hinnerker]

[Spotmatic]

[hinnerker]

[F16SUNSHINE]

Unless you are looking for perfect "Life Like" reproduction.
The concept of lens superiority is theoretical.

It's all in the Signature

The very thing that may make one lens the wrong one for a job.
May also make it the best one for another job.

Different brushes so to speak.

[hinnerker]

[Arkku]

[hinnerker]

[kds315*]

@henry, Peter, Andy: I cannot agree more!! It always reminds me of the guy who asked the famous master painter "master, what a wonderful painting - which brush did you use?" Same with lenses...

[hinnerker]

[hexi]

Oh well i won't go into debates, for me Zeiss are the best . I do'nt look for sharpness, a sharp image is not necessary a good image.

Just to say that Zeiss invented the Planar formula lens, which was copied with more or less success by lens makers of all brands, so here again Zeiss wins. All others lenses are Zeiss wannabe.


Am i biased ?


No. I just stated a fact

[Arkku]

[hinnerker]

Good statement.. and correct IMHO

The term sharpness is only one aspect..
"painting feature" of a lens is often more important.

See this picture.. taken with a cheap 1.2 Porst 55mm



Not sharp, but the use in this special situation to demonstrate the
Low Key tech.. perfect. It was not important, to use the sharpest lens i own.

The image shows more of the character from old slide..

Thats what i like in such situations..

Cheers
Henry

[Nesster]

However, going back to the OP - in shooting the backs of old refrigerators so you can read the sticker on the back - which lens is the better one?

[Arkku]

[Carlsson]

[scsambrook]

[estudleon]

The importance of the sharpness is a legacy that been born in the times of great format and very prone to flare and low contrast lenses.

Remember the necesity of sharpness in old fotographers (eg. F/64 ones)

With the little format and newer lenses, and just better lenses, the point is the new view about the IQ. Resolution power? Contrast? Yes, but saturation, bokeh, etc are into IQ too.

For a long time the sharpness was the abstract parameter used in the words world to define an object used in the visual world.

Rino.

[mflex-on]

[Orio]