Two versions of C-Sonnar compared (again)

[andtky]

If anyone is still interested I did another focus test of the two versions of the Zeiss C-Sonnar 1.5/50 ZM on Leica M8:

http://members.chello.sk/akratky/Tests/C-Sonnar.html

First 6 pics is the original lens adjusted for f/2.8, next is the new lens optimised to focus at f/1.5 at the factory. All pics are cropped.

I would say the new version is actually spot on at about f2 (with my camera), while the old one looks optimised for about f/4.

Andrej

 

[ampguy]

To my eyes, it looks like the original version is optimized for about 5.6 and the optimized version about f2.8 or f4.

Did you measure your angle and distance from the sensor plane to the focus line?

 

[andtky]

No, i just focused using the rangefinder. Then I shot at all aperture without changing the focus.
I did two sets of pics in each case with very similar results.

Andrej

 

[nzeeman]

i still think that the best solution would be to adjust lens for f2 instead of f2.8 and f1.5.
it is because i think that when lens is adjusted for f1.5 on 1 m - it has a lot of problems from f2 to the f4 on bigger distances...
i would love to see the test of focus shift of both versions on 3-5m distance if anyone can make it...

 

[ampguy]

I too would like to see a focus shift test for this lens

I too would like to see a focus shift test for this lens

1.5 to f8 would be fine. I use several markers (eyes of figurines) which are 1.50 cm behind, and in front of focal point. Maybe 2 tests, one at 1m, and one at 2m.

example with CV 40/1.4

i still think that the best solution would be to adjust lens for f2 instead of f2.8 and f1.5.
it is because i think that when lens is adjusted for f1.5 on 1 m - it has a lot of problems from f2 to the f4 on bigger distances...
i would love to see the test of focus shift of both versions on 3-5m distance if anyone can make it...