Summarit 50 2.5 is as aspherical as 50 2.4 lens, Skopar is not. But Summarit is M, not LTM.
50 2.5 Skopar is much more practical choice in LTM, IMO. Even now it is less expensive than Cron, yet, it has all metal build, modern focus tab and it has optics free of issues. Even filter is right size!
Just yesterday, while picking up lens cap for lens hood which is for Cron 50 IV (I think it will fit on Collapsible Cron as well), I was looking at one LTM Cron. Not trashed one, but it shows its age. Lens was looked after, clean, but the state of coating is alarming. Something like patina is starting to show up. Just like any old Leitz lens I have used including Collapsible Cron it is next to impossible to find one in same optical condition as modern Viogtlander or even old FSU lens. Well, aluminium exterior of FSU lenses needs cleaning now, but it is not big deal to polish it and repaint engraved numbers.
And I don't want to offence so valuable and kind person as Erik. I just would like to mention what on f8, nothing close in the frame type of BW pictures as above, anything is great. My 19$ Industar-22 was great on M3 once I shimmed it and so is great colimated J3 for FED-2 on M3 with HP5+ at f8 and on next to infinity focus. I'm honest here, every time I do pictures as above with something like Industar-26M (9$ lens) I question myself, why I need Summicron?
But every time I look at Summicron Collapsible portraits and close distance images (BW prints) I want one back.
🙂
Maybe I just haven't seen enough portraits with Color Skopar 50 2.5 which were as impressive for me as with Collapsible Cron.
Here is Collapsible Cron, split print, I slightly over-exposed it: