Focus issues

[dagimage2]

Having just bought a new lens and performed a few tests with it, I discovered something very disturbing, which is that my RD-1 focusses properly with one of my lenses, and severely front-focusses with the two others. With my Minolta 40mm (the main lens I use) the focus is spot on, but with my Canon ltm 28mm and my new ZM 21mm, when the rangefinder coincides on something about three feet away, the lens is actually focussed on something about 8 inches nearer to the camera. As the focus distance increases, the degree of front focussing seems to increase as well, although I haven't tested that rigorously.

I'm not sure how to address this problem. I know how to calibrate the rangefinder for infinity, and did that when I first received the camera. I think that calibration may have slipped a bit, but I'm not sure. And the problem seems to be with near focus calibration. But the fact that it happens with a couple of my lenses, but not one other, suggests that the one lens would also need adjusting. Which is puzzling, because I used that lens, and the canon 28mm, for years on two different CL bodies, and never noticed any focus issues with either lens.

Does anyone have any suggestions for confirming where the fault lies here, and what steps I should take to fix it? It's got me paralyzed a bit, and is very frustrating.

Thanks.

Dave

 

[LCT]

Got focussing problems with the M-Rokkor 40/2 as well but none with my 3 copies of the Summicron-C 40/2 despite its sloping cam. I don't know why.
See: http://photo.net/bboard/q-and-a-fetch-msg?msg_id=00M6Y5

 

[bluelight]

I have similar problem Dave,

I have three LTM lenses and all of them front focus. I ended up opening the top plate to adjust the baselength.

When I got the three lenses alomst focus OK close and infinity, I added a Nokton 35mm and now the inifinity focus is off only with the Nokton.

I did check collimation for one of the LTM lens and it is slightly off. Now I face similar problem.......

 

[Philip Whiteman]

I think this is a problem that many of us were unaware of when we all used film rangefinder cameras (when we generally took far fewer exposures and put down the odd dud result to operator error or subject movement)

My 50 mm Summicron focuses perfectly on my R-D1, my seemingly less demanding of the rangefinder 35 mm Summicron tends to back focus by a hair, my 28 mm Ultron back focuses by enough for me to deliberately misalign the rangefinder on the 'closer' side to compensate (although the effect varies with working aperture, which is a known aspherical lens issue) and my 25 mm Voigtlander is spot-on!

At least the instant focus check – especially with R-D1s software – allows you to recognise and work round the problem…

 

[dagimage2]

That just seems kinda crazy. So is this due to something like differential wearing of the focus couplings for differently aged lenses, or manufacturing tolerances, or something?

Is it possible to have the lenses somehow all calibrated so they're all consistent, so I can calibrate my rangefinder and have them all work properly?

Or is there anyone who services these things who can calibrate my rangefinder so that it's at a reasonable compromise between all my lenses?

Should I have Epson check out the rangefinder and make sure it's ok? (I think I'm still under warranty).

 

[LCT]

...Should I have Epson check out the rangefinder and make sure it's ok? (I think I'm still under warranty).

Normally yes but you can't be sure if the new body will be any better as in most cases Epson just replaces the body.
If you don't fear to void the warranty, do again what you did previously but differently: calibrate the RF so that it is accurate on subjects between 2 and 20 meter more or less.
That is what i do personally. I've been using more than a dozen M lenses in 3 years with the R-D1 and in most cases it adresses the issue.
Otherwise take a look at my link above about the Rokkor 40/2. It is actually my only lens which is back-focussing significantly. Difficult lenses like 50/1.4 at full aperture are just OK. So if you try my trick above it is well possible that your Rokkor will be out then, you can't be sure if you don't try it anyway.