M8 Focus Problem

[gerasdoc]

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I recently noticed that the rangefinder on my M8 is not in focus at when the 28 cron asph on it is set at infinity. Is this something that I can correct myself?

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[carstenw]

What is the situation with your other lenses, and what other lenses do you have? How is it when focused up close?

[gerasdoc]

I have several other lenses that seem to be focusing correctly. The exception is the noctilux, but I have atributed the focusing difficulty with it to it's limited DOF and my inexperience. Do I need to do a detailed analysis with all of my lenses?

[Shootist]

You need to check EACH LENS for proper infinty focus. You do that at night with a far off STAR (IE true infinity).

If most lenses make the images line up in the viewfinder at infinty but some don't then you need to take the lenses that do line up the images and do a close focus test. If those same lenses focus correctly close up, 3-4-5 feet (1-2 meters) then the lenses that do not line up the images at infinty need to go in for adjustment.

 

IF those same lenses, or all lenses, don't focus correctly close up then your camera is out of adjustment and some of your lenses may also need adjustment.

 

Yes you need to do a detailed focus test and rangefinder test, close up and at infinity, with each lens.

[gerasdoc]

I have seen a number of references to the rangefinder needing adjustment when there are focusing problems. How does one determine if it is a rangefinder problem or a lens problem?

[jdos2]

The "absolute measure" of infinity on an M mount lens is a known distance inside the body from the lens mount. This is what makes it hard to adjust the rangefinder- it's no Contax "infinity is set at zero degrees" mount, where one KNOWS where infinity HAS to be.

 

What I've done that works well enough was to pick the lenses that need to focus well and make sure that they do on my camera, nudging the end-pivot just a touch when things start to go south (I carry my M8 everywhere, and the rangefinder does show change after a few weeks). I can focus my 90mm Summicron well enough, and when that was very (very) carefully adjusted, I double checked against a star and found the rangefinder lined up perfectly at infinity.

Sadly I confirmed two new lenses (not Leica) are poorly calibrated- and one has been out of my hands for two months now- back at the factory.

 

What would be nice is if someone sold an inexpensive calibration tool- a lens mount with a precision tang to engage the rangefinder to the appropriate infinity distance. It would THEN be much simpler to set it correctly. Until then, it's still a guessing game, even with very educated guesses.

 

J

[1234]

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The danger in reading the many threads on this particular topic on the forum is that at least 95% of the entries use imprecise terminology and/or advocate voodoo procedures and/or show misunderstanding of basic laws of physics and lack of common sense, making it difficult to say the least for someone in trouble to know what to do.

[Shootist]

The danger in reading the many threads on this particular topic on the forum is that at least 95% of the entries use imprecise terminology and/or advocate voodoo procedures and/or show misunderstanding of basic laws of physics and lack of common sense, making it difficult to say the least for someone in trouble to know what to do.

 

Sorry but what the hell does all that mean.