3 ZM lenses reviewed

[jsuominen]

Thanks awilder. And CV 50/1.5 is a lot of cheaper than ZM 50/1.5. Although I'm still interested to buy ZM maybe someday, too. I have also a Sonnar 50/1.5 lens from 1950's.

 

[Mazurka]

I think these soft filters produce their soft effect through means other than spherical aberrations, so it makes some sense there'd be no focus shift.

Doug, the Softar and Hoya Softener have no other means to achieve their effects.

Sadly I could not make either of them work reliably. Luckily I bought from Tony Rose and he was outstanding in his handling of the problem. I have been using a Planar and have never found a better 50mm lens...ever...including all my various Summicrons...so there.

Last week I shot a few rolls on my great old IIA with Sonnar F1.5 and I'll be damned if I found any notable focus shift in that amazing lens. It is spot on from f1.5 down at all distances. I specifically did a few shots at F1.5 and then F2.8 to see if I could induce a notable shift and found nothing.

Huck, I've raised the following point before. Now I'm quoting Dan from another thread hoping you (or anyone else) will at last "counter" me by explaining why the Contax-mount version, being a 50+ year old design, does not suffer from focus shift.

Here's my theory: the C-Sonnar could be a straight translation from the Contax version with the centre element of the 1st triplet eliminated. The root problem being the Leica and Contax RFs are calibrated with different focal lengths in mind, i.e. "50mm" is not the same on both systems. The C-Sonnar behaves just like a Jupiter-3 (a Sonnar clone) used on a Leica: http://www.dantestella.com/technical/compat.html

 

[Dan States]

Since I've popped up again in this thing I'll add that I found focus shift to be MINIMAL at close distances. I made several portraits at .9 meter and while it was a bit off it was still usable.

My problems occured when I used the lens in the 3-5 meter range. At these distances I found a shift of focus of about a meter, as noted by another poster earlier in what was said to be a technical bulletin from Zeiss. At that distance the amount of shift is not covered by the natural depth of field of the lens at normal magnifications (8x).

Has anyone else tested the lens at longer distances?

I attached a crop of a test shot I did at F1.7 and 1/250th. The point of focus was the legs. You can see that at that aperture and distance (about 3 meters) the point of focus is ahead of the subject by about .6 meters.

Thoughts?

 

[Mazurka]

First, there are six legs in the pic. Which ones are you talking about?

Perhaps you're talking about the dog because the human legs look closer than 3 metres (or 9'10") away. However, the focal point is more than 0.6 metres (or 2 feet) in front of the dog.

Otherwise the pic was a small crop from the original, in which case all bets are off.

 

[Huck Finn]

Huck, I've raised the following point before. Now I'm quoting Dan from another thread hoping you (or anyone else) will at last "counter" me by explaining why the Contax-mount version, being a 50+ year old design, does not suffer from focus shift.

Here's my theory: the C-Sonnar could be a straight translation from the Contax version with the centre element of the 1st triplet eliminated. The root problem being the Leica and Contax RFs are calibrated with different focal lengths in mind, i.e. "50mm" is not the same on both systems. The C-Sonnar behaves just like a Jupiter-3 (a Sonnar clone) used on a Leica: http://www.dantestella.com/technical/compat.html

Fascinating! Thanks for the link.