J12 convert

[ZorkiKat]

so a j12 will not fit a contax lla?

joe

However, the other, non-normal Jupiters (-9 and -11, 85mm and 135mm respectively) will work fine on it. Ditto with the turret finder. My contax IIa had a Helios-103 when I got it.

 

[ZorkiKat]

Hey Alexander,
To my knowledge, the LTM J.12s date by first two numerals of serial number, --> #5201944 is 1952 vintage. Not sure about the CBMs... anybody?

Reagan

Yes, the CBM Jupiters coming out of Arsenal and other factories also used the year prefix numbering system.

Jay

 

[back alley]

No Joe, the CBM J-12 won't go on a postwar Contax IIa/IIIa. Same could be said of the prewar CZ Biogon for the Contax II/III.

Years ago, I bought my first J-12 with the intent of fitting it on my Contax IIa. Found that it wouldn't because the IIa/IIIa had a 'lump' in their throats (covering the lower part of the shutter roller) which prevented the J-12's large protruding rear from getting in fully. So rather than have an 'orphaned' lens on hand, I got a few Kiev RF for it instead 😛 ...

Jay

thanks jay.
brian is sending me a j12 for the nikon s2 and i assumed i could use it on the contax lla as well.

 

[Xmas]

Joe

Please dont try it, both the j12 and origional Biogon are not compatible, with the IIa (or IIIa) shutter surround. You will damage the coating for sure.

The j12 is really marginal on Contax II and Kiev, about 1mm clearance, negaitve clearance with the post war models. Zeiss did a post war 35mm that will work!

Noel

P.S. Sorry Joe did not read last post...

 

[back alley]

...learning every day...

 

[Xmas]

Joe

I thought you were getting a Nikon or CV 35mm?

The J12 on the Nikon, will not need a filter but some will flare badly, in bad conditions, so if you do use a filter you will then need a deep hood, I use a oly OM 28mm filter on a 40.5-49mm step ring, when I fit a filter.

I dont worry too much about flare, not have a bad case yet. But then we get cloud here most of the time.

I'd also make sure the rear bevel of the optic does have black paint on it, many dont, the bevel will give strange effects if it is not painted.

Noel

 

[back alley]

noel,
i decided on the cv 28 for the nikon and then brian had a j12 (from frank) that he worked on and it's being sent to me.
so, i'll have 28/35/50 covered.
a perfect back up and a perfect get away kit for when i want to go back to basics, so to speak.

i like hoods so maybe i'll start looking for one for the j12.

joe

 

[varjag]

Vented 40.5mm S&W hood on black J-12 looks like at home and doesn't seem to vignette.

 

[back alley]

Vented 40.5mm S&W hood on black J-12 looks like at home and doesn't seem to vignette.

cool, i have one of these for the 50/1.5 cj

joe