Front focusing - feedback needed

[ivancook]

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I have an M11 that I recently purchased used and a brand new 35mm Summilux Close Focus. Rangefinder patch seems to be dead on at infinity (from looking at stars and the moon) and actual photos are extremely sharp at infinity. Also, rangefinder patch and actual focus seem perfect at mid distance. The issue is when shooting around .7m the actual area that is in focus is about 2" in front of where the rangefinder shows focus. For example, in the attached image I shot at about 45 degrees to the ruler and the rangefinder patch shows focus at 15" but actual focus is closer to 17.5". Unfortunately, I have no other lens to test. Is this just to be expected given the mechanical nature of the rangefinder and the narrow DOF at 1.4 or does it need calibration? I'm fairly handy, and I've read through prior guidance on here about calibrating the rangefinder. Hoping to get a bit of feedback before diving in. If the infinity adjustment is almost imperceptibly off in the rangefinder patch, could that yield these sorts of results at close focus or is this more likely to require adjustment of the arm length as well?

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[Derbyshire Man]

New or used?

[JNK100]

3 hours ago, Derbyshire Man said:

New or used?

Lens is new and camera used 

Edited 9 hours ago by JNK100

[ivancook]

4 hours ago, Derbyshire Man said:

New or used?

Lens is new and camera is used but shows no sign of damage or prior adjustment. 

[ivancook]

Looking at the moon again this morning and if anything focus might be stopping just a hair early of perfect alignment in the patch. Could that equate to a few inches off up close?

[jaapv]

No. It is more likely that the shims of the FLE group are out of tolerance.

[Derbyshire Man]

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Where are you based Ivan?

[ivancook]

3 minutes ago, Derbyshire Man said:

Where are you based Ivan?

Texas, USA

[Derbyshire Man]

Tricky. I’d head to the nearest shop with some more lenses to see if you can get a feel for which half is the problem. 

[ivancook]

Am I correct in assuming that adjusting the infinity point in the rangefinder only impacts the view in the rangefinder patch, and not actual infinity focus from the lens?

[pop]

3 hours ago, ivancook said:

Am I correct in assuming that adjusting the infinity point in the rangefinder only impacts the view in the rangefinder patch, and not actual infinity focus from the lens?

If you focus using the scale on the lens barrel, then you're right. If you focus using the rangefinder (which seems to be the whole point), then adjusting the rangefinder will affect the focus of the lens. The infinity stop may or may not still be off, though.

[ivancook]

I wonder if there's no issue at all and maybe I'm just nitpicking and hitting up against the limits/tolerances of the system. At .7m, the DOF is about 2cm. I'm aiming at the 5" line, and the critical focus looks like it's starting just 3/4" in front of where I'm aiming. From reading other threads it sounds like while the FLE has minimal focus shift, it does still have some focus shift and this degree of slight front focus may be part of the strategy to balance for that. Not sure it's worth chasing down. For real world scenarios, the limiting factors are likely going to be my eyesight or hand/subject movement.

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