How do you know you have back or front focus problem

[woodda]

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Hope you can help. I recently bought an M8 and the focus seems not as good as expected. I would greatly appreciate soem guidance to check if I have a problem with the rangefinder or the so called Back focus situation

 

Thanks in advance

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[jaapv]

If you don't know you don't have it..... Seriously, put the camera on a tripod, focus on one book pulled forward in a bookshelf and position some other books forward and backward and study the resulting picture. Having said that, a lot of apparent focussing problems can be traced down to a minor discrepancy in vision of the photographer, not noticed before. A rangefinder requires good vision, or good correction, to function well. Start at the beginning, your own eyes, suspect the camera next and the lenses last.

[woodda]

Is there a simple test to confirm

[jaapv]

Sorry, I posted in two surges.

[jfgilbert]

There is a test chart and prodedure (written for DSLR, but that can easily be adapted to the rangefinder) here:

http://focustestchart.com/

Hope that's what you were asking for.

Jacques

[colorflow]

I shoot a tape measure (or yard stick) on the floor with the camera on a tripod looking down at about 45 degrees. Use time delay exposure. Focus on a certain mark and see where the actual focus is in the photo. This provides an easy way to see how far off the focus is. Remember to multiply the focusing difference on the yardstick by 1.414 to calculate the actual amount of front or back focus. Do that with several lenses or bodies (film bosies also helps) if you have them to see whether the lens or M8 is at fault.

 

But I agree, suspect your own eyes first.

 

I found that all my lenses shift their focus back when stopped down. Some backfocus and others front focus when wide open. One was not acceptable in my opinion, so it will go back to Leica for adjustment.

 

Hope this helps,

Alan

[woodda]

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Many Thanks, How do you know if it the camera range finder vs the lenses

[colorflow]

Many Thanks, How do you know if it the camera range finder vs the lenses

 

I ran the test on several lenses and also with a M6. I concluded the M8 rangefinder was ok since some lenses front focus while others back focus and no real difference from the M6 with the problem lens. I will run some more tests with the M6 with all the lenses to compare with the M8 results.

 

Alan

[woodda]

Thanks for the suggestions it seems to be OK must be me and being optermistic re shutter speed. Odd as I cannot remember having this problem with my MP last week. Maybe digital is more sensitive. Is the 1.25 Magnifier critical.

 

Any views

 

Cheers

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