CZJ 15cm f/4.5 Tessar Question

[loccdor]

Hey guys, I need to determine lensboard size for this lens I don't yet have.

So I used the front picture, went in the old CZJ catalog and found this lens takes a 42mm push-on. By ratios, that means the outer diameter of the lens is 76-77mm.

Then using the back picture and that same measurement, with ratios it seems the retaining ring is 53mm outer/45mm inner diameter give or take.

Does that make this a copal/compur #2 52.5mm size? Thank you.

 

[Dan Fromm]

Wait until the wretched thing arrives. Between-the-wars shutters don't conform to modern standards. Oh, and by the way, in addition to the retaining ring's inner diameter you need to know the thread pitch.

 

[_T_]

I've done dead reckoning of the size of gear by measuring a photo before and it's only useful for order of magnitude estimations. Knowing the measurements of the photo doesn't put you in any better position to know which lensboard size you need than straight guessing.

 

[JensH]

Hi,

I have a CZJ Tessar 4.5/15cm in dial set Compur #2 on my Zeiss Ikon Ideal 250/7.
Looks exactly like your's, speeds up to 1/200s. Takes 42mm push-on filters.
Same bayonet mount like your's, same mount like my 6.3/21cm in Compound #2.

Anyway I just measured the outer diameter of the mounting thread as 43.8mm, the lensbord has a 44.2mm diameter hole.
The shutter is too large for a modern #1 lens board. Just tested that.

Can't tell the outer size of the retaining ring, as my Ideal doesn't use any due to it's bayonet.

Hope this helps a bit
Jens