Is it a Sonnar lens

[nikonbob]

I can't find any info on the Topcor 4.4cm F2 lens and was hoping that someone here might know if it is a Sonnar type.

Bob

[Andrew]

I cant say if it is one way or the other yet Bob, i'm not much help i'm afraid...been looking but cant find anything definite..is there a reason you suspect it a Sonnar type?(because of the f1.5?). this is on a 1957 35L topcon no doubt?


so far i have conflicting info, even one that could suggest its a 3 element (i doubt it, though it seems some immediate cameras before this did have 3 element though), but other source seems to say its composed of 6 elements but it doesn't seem reliable either. for the SLRs it seems they did make some fancy glass and they also made some UV lenses with 6 elements. some other lenses were of Gauss type and others different

i would pull it apart to look at it LOL, it appears to be easy enough, i read somewhere earlier on, so only from memory it went something like, unscrew the lens ID ring with rubber ring, flip out the next cover ring, undo 3 screws, lift out another ring, then 4 screws, then the front lens group can be removed, the rear removes easily with a common lens spanner and needs to flipped on its side to take out through the film plane....something like that, if you felt like it i could find the page again somewhere but it looked pretty easy and straight forward

interesting little mystery, i like to know myself now!

btw does it appear to have yellowish glass in the lens, that comment seems to pop up quite a bit (and they do seem to mean the glass is yellow! weird! unless it is using, i forget how to spell it just now, thorium i think it is in the glass which turns yellow over years, radioactive) and they say it gives a yellow cast on colour film but is excellent for B&W....otherwise i suspect they are confused and mean a yellow lens coating ..or perhaps translating from Japanese is not that good

[nikonbob]

Andrew

Glad to see that I am not the only one who is having trouble finding much on the 4.4cm/F2 lens on the Topcon 35-L. No reason to suspect it is a Sonnar other than the way the photos come out which got my curiosity up. I think I have that page bookmarked on the lens tear down but not being good at that sort of thing I really do not want to attempt it. This particular lens has a blue/purple cast to my eye. If I never find out I'll just keep enjoying it. Works well with both colour and B&W. Thanks for your effort.

Bob