Zeiss C Sonnar 50mm ZM

About a year and a half ago, I finally broke down and purchased the Zeiss C Sonnar T* 1.5/50mm ZM. I don’t know why. I had been intrigued by it for years, but questioned how much I’d use it when I already had the wonderful Leica Summilux-M 50mm ASPH. I also have a classic Sonnar design in the Nippon Kogaku Nikkor-S 50/1.4 LTM lens, so why spend more money for a remake? Well, the Nikkor is an interesting lens, but the ergonomics of it are funny compared to modern lenses, it flares oddly, and it is decidedly soft wide open. It is a nice lens, but I moved on from it years ago.

Zeiss was running a promotion for the 50th anniversary of the Apollo missions, and given my current employer, how could I resist that? Furthermore, as I had been shooting Sony more than the Leica, the 50 ASPH was not getting used much, and the it appeared to me that the C Sonnar wasn’t too bad on the Sony (unlike the 50 ASPH). So I finally succumbed.

Note: I don’t shoot as much as I should, and when I do, apparently it’s all cats (forgive me).


The lens is good. Nice and compact, good hood, etc. Don’t really like the 1/3 fstop clicks on the aperture ring, but this is a ZM, so that’s what you get. If you’ve shot a ZM lens, nothing new or surprising here.

The most annoying thing about the lens is the 0.9m minimum focus distance. Not a problem 95% of the time, big problem 5% of the time. I’ve been shooting rangefinders for long enough that I’m okay with the normal 0.7m minimum. With a 50mm lens, I’m used to a certain tight framing with a 50mm, and I can’t quite get that with this lens. Of course, on the Sony, I’m spoiled with much short minimum focus distances, but I haven’t really internalized that yet.

murphy sleeping

Focus shift

Focus shift, the thing that scared me away from the lens, and that is a constant topic of discussion, isn’t that bad. It’s there for sure, but find out where your lens is calibrated (mine appears to be f/1.5) and you are good. f/2 isn’t too bad, but then you go off a little bit until f/4–f/5.6. Frankly, my conception of it isn’t fully formed yet because I have been shooting it a lot at f/1.5.

I must admit I’ve not developed any of the few shots on film I’ve taken with it, but I would be surprised if the shift would be that bad or noticeable on a film like Tri-X.

On the Sony, of course, there’s no issue with shift. The same is true if you are using liveview on a Leica.


I like the look of it. At f/1.5, the aberrations in the image give a very nice halo around certain elements right outside the focal plane. In the following photo, you can see the effect if you look closely at the cat whiskers (see the crop). It’s true that this likely wouldn’t be visible if the print or enlargement wasn’t big.

whiskers out of focus

I have been shooting it mostly at f/1.5, but between f/2.8 and f/4, the image cleans up quite a bit and is reasonably sharp. Not sharp sharp, but good enough. Get another lens if you need the resolution. For more candid-type photography, I think it is sharp enough. It is noticeably less sharp wide open than the Summilux ASPH, but nothing that is concerning. It’s also more contrasty wide open. I’m not sure if that is true across all examples of these two lenses, but my Summilux is less contrasty at f/1.4 and on par with the C Sonnar probably around f/2.

I think I’ve noticed it get a little squirrely on the edges on the Sony, possibly due to the different sensor–see the bush above the fence on the right hand side.

hatchet throwing - funny background


I like the lens a lot, and shoot with it more right now that the Summilux ASPH. If I were going on a trip, I’d probably take the Summilux for versatility, but I’d be fine with just this lens if it was my only 50mm. It’s all been said before because this lens has been around for quite some time, but a Planar or Summicron is the better all around lens, unless you know you want this one. Nowadays, I’d probably recommend one of the Voigtlander 50mm lenses as a good value proposition; the new 50/1.5 II looks great1, the prior Nokton Aspherical seems nice, and the upcoming APO is probably going to be fantastic.

How often does one get the chance to buy a classic design like the C Sonnar, with just enough improvements to make you not feel like you are using an antique, but not so much as to ruin the magic?

More photos from this lens can be found on flickr.

  1. It also looks a lot like the C Sonnar. I bet it is going to be a bit like a cleaned up C Sonnar: ‘better’ performance, less character. ↩︎