Front-focus with Leica M3 & 50 cron

Sweet Baby Boy · Jun 22, 2014

Hey everyone! So I finally got my paws on a Leica M3 and a 50 f/2 Summicron version 3. I totally love this set up but I'm running into some nasty front-focusing issues across the range of focus. It seems I have better focus towards minimum distances but I still can't nail a tack sharp exposure. The 50 cron just arrived from a CLA so I'm already stretched on money.

I tested the rangefinder at infinity on some sailboats towards the horizon and it appeared to be properly aligned. It is a pretty foggy afternoon in Chicago though...

Is there any other tests I can do to confirm if it's the lens or rangefinder? I found a lil' test on this site but I'm not sure if it's legit. http://rick_oleson.tripod.com/index-123.html (Last photo)

One more thing. I hear the M3 is pretty easy to adjust. Anyone try adjusting their horizontal alignment? I'm tempted to do this myself to save money and time.

Thanks!

P.S. I brought samples.

blockend · Jun 22, 2014

Difficult to believe it's the lens. Front focus, or focus shift as it is otherwise known, occurs on some wide aperture lenses (typically f1.4 and under) when they are stopped down slightly, usually showing around f2.8 to f4. A misaligned rangefinder is much more likely.

Sweet Baby Boy · Jun 22, 2014

Thanks for the reply. I really hope it's the RF and not the lens.. Sherry Krauter also mentioned it being more likely the RF being at fault. I do have some additional photos taken stopped down and they show slight signs of focus shift.

The lens and patch hits on infinity so it isn't back-focusing. From what I've read, that means I'll need to adjust the horizontal eccentric screw clockwise.

If I were to do this indoors, does anyone know if this diagram actually works?

chriscrawfordphoto · Jun 22, 2014

Rangefinders on Leicas do go out of adjustment over time. I've had to have every one I have owned adjusted after I bought it. Every one. Lenses for RF camera can also go out of adjustment but this is less common than the camera going out.

Sweet Baby Boy · Jun 22, 2014

I see. Was it pricey to have your RF adjusted? I'm leaning towards sending it out since every tool I own doesn't catch well with the horizontal RF screw. :/ About to go back out and test infinity again since the fog has lifted.

chriscrawfordphoto · Jun 22, 2014

Don Goldberg charged me about $100. Was worth it; he is the only Leica repairman I have tried who was able to get mine focusing absolutely perfect, not even a millimeter off.

Sweet Baby Boy · Jun 22, 2014

chriscrawfordphoto said:
Don Goldberg charged me about $100. Was worth it; he is the only Leica repairman I have tried who was able to get mine focusing absolutely perfect, not even a millimeter off.

Youxin Ye just referred me to DAG. He said Don has better equipment for obtaining precise focus calibration so I'll probably have to go that route and give him a holler. I've heard nothing but good things about DAG..

Xmas · Jun 22, 2014

The registraction plate distance needs to be correct and parrallel to film gate.
Then the two screws on the rangefinder arm (eccentrics) need to be set together at 1, 10 meters and infinity the two screws interact.
If the rfdr has been damaged it may need top off first.
It is easy to reset infinity but leave the other two off.
But the lens may be the problem instead... they also have many adjustments...

Pioneer · Jun 22, 2014

Don is very, very busy. Sometimes it can take awhile to get things back.

Call him first, let him know what you want, then get a time quote on how long it will take him to do the work.

Just sayin...

Patrick Robert James · Jun 23, 2014

If the rangefinder is aligned at infinity it is either completely messed up or the lens is way off.

I know the first version Summicron's lens block unscrews from the focusing helix, so if that is the case for your lens, someone might have put a shim in there that shouldn't be. You may want to check that out.

Don't screw around with the rangefinder mechanism yourself. If you aren't sure what to do, send it to Don or Sherry Krauter (sp?).

Sweet Baby Boy · Jun 23, 2014

I managed to slightly correct my RF at infinity but I figured it'd be best to recalibrate everything. I just sent my M3 and Summicron v.3 off to Sherry Krauter. I considered DAG but I've heard turnaround times are a bit long despite his quality work.

darkosaric · Jun 24, 2014

When it will be back - you can enjoy for many many years . Just be careful on close focus: M3 goes up to 1 meter, and summicron v3 up to 0.7 meters.

Xmas · Jun 24, 2014

darkosaric said:
When it will be back - you can enjoy for many many years . Just be careful on close focus: M3 goes up to 1 meter, and summicron v3 up to 0.7 meters.

Some have been (or can be) 'enhanced' to work ok to 0.7 or so.

Quick email to Sherry... needed...

But it is bad setting it at infinity the rangefinder is not like a SLR where infinity is a good datum, instead setting it to 12 foot with arm pivot eccentric is better if you shoot at 12 foot.

For a full calibration the two eccentrics need to be at the single positions that minimise the error at 1m 10m and infinity.

Pigs to get spot on.

If you drop the camera and the lens needs new hood you need to check infinity otherwise the rangefinder won't change over decades..,

Patrick Robert James · Jun 24, 2014

As long as you are getting it looked at, have Sherry convert it to .7 meter focus. It is easy to do and you can benefit from all close focus lenses. Mine actually focuses a little closer than .7.

Front-focus with Leica M3 & 50 cron

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