Zeiss Sonnar 50mm f1.5

[ekphrasis]

just to be clear, I'm not complaining about this aspect of the lens. I simply haven't used this lens before and was wondering if this was characteristic of the lens or if it was something with the copy that I got. I hadn't noticed it on the photos that I took with the summicron.

 

[Archlich]

Besides the coating, the C-Sonnar is not a very modern lens optically, thus the "C" (likely for Classic). People get it for the soft rendering and vintage signature, not resolution (which is further compromised by focus shift). Consensus had been reached long ago that it's not as sharp and "modern" as the ZM Planar. Little surprise it's outperformed by the Summicron as well.

It's so undercorrected that it introduces all kinds of artifacts, especially on digital. So yeah, what you see is normal behavior.

If you want a relatively modern standard lens that doesn't break the bank - try the CV Nokton 50/1.5, both the older versions (in LTM and M mount) and the hot new one just announced today with all new optics (hasn't hit the shelves yet, but I'm pretty sure that it's at least gonna be on par with the Summilux ASPH). The Planar is excellent choice too.

 

[Richard G]

The Sonnar is very sharp in the centre even at f1.5 if you’ve tamed the focus shift. At f5.6 it’s still special. And at that aperture and smaller it’s as sharp as anything else stopped down. The C is also for compact. It’s smaller than the Summilux, Summilux ASPH and Nocton 1.5.

 

[ekphrasis]

thanks for this information about the Sonnar--this is all good to know. I bought it because I liked the vintage quality in several of the images I've seen others post. I'm not overly concerned with hyper-sharpness (and for that reason did not purchase the Planar); I primarily take pictures of people and appreciate the bokeh on the Sonnar.
I think that my initial reaction was to the fact that my first roll of film didn't look as sharp as pictures I'd seen online (or with the vintage Summicron I have), but it seems that my issue may be user error (focus) or perhaps the old film stock on my test role, or a combination of the two. I'll shoot more rolls and work on mastering the focus shift. Thanks again for you input!

 

[Scrambler]

just to be clear, I'm not complaining about this aspect of the lens. I simply haven't used this lens before and was wondering if this was characteristic of the lens or if it was something with the copy that I got. I hadn't noticed it on the photos that I took with the summicron.

I can't definitively comment on the "is it your lens or all C-Sonnars" question.

I reaffirm that there is fringing (green) in the same location in the Summicron shot. You are not seeing purple fringing: but you ARE seeing green fringing.

Purple fringing with lenses is common. Green fringing uncommon. I'm not an optics expert but would guess that the Sonnar doesn't have as stringent colour correction as the Summicron due to the design limitations. That means I'm guessing it will be all C-Sonnars, not just your example.

I could test other Sonnar designs but that doesn't really answer your question, because they should all be less accurately corrected given they range from 40 years old to 80+ years old, and were all designed by paper-and-pencil maths.