Which M 90 'cron is prefered?

[jhodges]

I have an M2 and am looking at getting a 90 for it. I haven't

decided on the 'cron or elmarit yet. That's a decision I'll make

when I decide to pull the trigger. My only question is, what is

prefered? The 48mm version or the 55mm version? Is there a

difference in optics or was it just the barrel design that changed?

Would the 55mm diameter cut into the viewfinder of my M2

significantly? Thank you in advance for any help.

 

John

[Robin Smith]

John

 

The 48mm is older and larger and not as good at wider apertures. The 55mm is a 1980 reformulation and it is a very nice Mandler-type Canada lens of improved performance wide open. It commands a c$300 premium over the first version. The latest is the APO-ASPH 'cron which externally looks much the same as the 1980 version and is expensive and utterly superb by all accounts, but perhaps too sharp for a flattering portrait.

[mark_sampson]

The early (1957-80) 48mm filter Summicron is a real howitzer. I used one for almost 20 years and never liked the huge size and weight. No problems optically though.

[feli]

I would recommend the last pre-ASPH Summicron-M. It's the most compact and best performing Cron of the old bunch. From what I hear the ASPH is in a class of it's own, but may be too sharp for portrait work.

 

feli

[andy_piper2]

John: the 55mm-filter 90 is shorter than the 48mm early version, so viewfinder penetration is mostly a wash (with maybe even an edge to the 55 - which was actually originally a 49mm for its first year or so, but with a thicker rim outside the filter threads that carried the serial number/Leitz engraving - when Leica switched it to 55mm filter they put the engraving INSIDE the filter threads).

 

There is a substantial difference in the optical designs. The original 48 'cron was a true 90mm lens (e.g. the optical center is about 90mm from the film at infinity focus). The 1980 redesign is a telephoto design - the optical center is closer than 90mm to the film at infinity, so the lens is stubbier.

 

At close focus (lens extended to maximum) and with the lens hood pulled out - all 90 f/2s will block an arc of the 90 frame that extends at least 2/3rds of the way to the corner of the RF patch.

 

With the exception of the 90 f/2 APO, any Leica 90 f/2.8 outperforms any Leica 90 f/2 at most apertures for resolution, although the differences get quite small in some cases. If you need f/2, you live with it.

 

The pre-APO 48 and 55/49 versions are pretty close for resolution - but the 'tele' 55/49 version has more contrast - sometimes a lot more.

[david_kieltyka1]

IMO the last pre-ASPH design is the best of the bunch. Wide open performance is great for portraits and just fine for everything else. The lens is lighter and more compact than earlier versions. It doesn't intrude into the M2's 90mm frameline.

 

-Dave-

[albert knapp md]

Depends what your goals are. For most purposes, sharpness is

key. Therefore, I have and love the 90mm F/2 APO. It is simply

amazing.

[robert_bouknight]

Hi John, Own the 90 APO now and owned the 55mm version just prior. One small change that has not been mentioned is that the redesigned larger aperture ring on the APO version reduces accidental disturbance of the stops when focusing, for me. Bumping the aperture ring on the previous version is not that bad on an M6 with light meter, but was a pain when I was using it on my meterless M3. Also, I do find myself using the APO at f/2. Careful focusing required, but results can be quite nice, especially in low light, low contrast situations.