Amadeo Contax LTM adapter focus problem

[pb908]

I have been hanging around this contax RF forum for a while. I have Contax IIa which I painted black, a nice Contax II, and as well M/Ltm body. My lenses collection is growing up by now, 3pcs of 5cm f2 sonnar (all CZJ, prewar uncoated, prewar coated, and a postwar coated), one 5cm f1.5 uncoated, one 8.5cm f2 postwar coated, and lately, a 13.5cm f4 uncoated.

so the idea of getting a contax to Leica adapter is going to be great, in fact, I already bought one, shiped from amadeo directly to my country, take a month to come. I bought the ltm one, as I can use it in my IIf and I can set the frameline with a simple ltm to M adapter for my M body.

in the first time, when I put my 5cm f1.5 on my RD1, i got front focus problem, then I put all other lenses, 3 5cm f2, 8.5cm f2, all give me front focus. So at the end, in order to use those lens, I need to reshim ALL of my contax lenses (reduce the shim originally installed). This works so far.

but as I told you before, that I just got a 13.5cm f4 uncoated, it gave me front focus as well before I remove few shim from the lens. I have tried to change the ltm-m adapter, from a cheap one(fotodiox) to the expensive one (voigtlander), and both have the same front focus problem.

Is this a coincidence that ALL (6) of my lenses (from different years/models/design) gave me front focus problem? i don't think so. i check few threads on RFF regarding amadeo's adapter and found some people reported the same problem.

i have shot few rolls of film, using most of those lens on my contax IIa/II just before I shimmed them.. during this Christmas weekend I scanned few rolls and almost all show that focus was correct.
but now, I have a doubt that all of my lenses will focus correctly on my Contax..

what to do? Returning amadeo's adapter is not good idea as I already shim all my lenses (and enjoy it much), and i don't think i will not get the same problem in return. My only option is to spare one 5cm and calibrated it for my film contax RFs.. any ideas?

for any of you having amadeo's adapter, do/did you get the same focus problem (without shimming the lens) ?

 

[Mister E]

Are you sure you have a Contax and not a Nikon to M adapter?

 

[pb908]

Yes, it is a contax.. There is a word CON on the body of adapter..

 

[fbf]

do they work fine on the ltm body? The more important question is which ltm-> M adapter are you using on the rd1? If they aint' Leica, CV made, I think you have the answer. I actually had problem with early Leica made adapter so the only adapter I would trust is the CV type II

 

[pb908]

I have tested the adapter + shimmed lens with my IIf, and I can say focus is correct, as does on RD1 with fotodiox & CV adapter. i assume if the lens is unshimmed(original condition) it will be front focus badly as what I had tested before (with rd1).

that's why I am suspecting the adapter is the culprit..

if I see the contax adapter from the back, it has a stepped area (around 1mm thick) between thread and holding area. I believe if this is filed down correctly, all sonnar lens will be focused perfectly.

i even read that even brian sweney said he need to shim his lens as well. But I can't write the link here as I reply/write this thread from my phone..
try to google contax ltm adapter on RFF, you will find it..

 

[pb908]

Bump... Any user have the same problem?

 

[monochromejrnl]

I would suggest contacting Amedeo to explain what you are experiencing with front focusing. I suspect he'll offer to replace it.