Backfocus - M8 or lens or both

[MJones]

I've been using M8 for about 6 months and love the RF. I've searched some threads and other forums for lens focus issues and found a few things on this topic but want to ask specifically for my lens set.

I've recently picked up a used 35/1.4 asph and 75/1.4 (both in excellent to mint exterior and glass condition) but both exhibit some backfocus, especially at 1.4 and at closer distances. I've seen it written in other posts & forums that this can be an issue to these lenses especially the 35asph-lux. So this may be what I have to live with but...

I also have a 50lux (new) and Zeiss 35&25 and have used a Leica 24&21 and none of these exhibit any sort of back focus. I've tried all the same settings and conditions as with 35lux and 75lux but this lens set does not back focus for me (which is good).

Anyone with similar experience?
Is this more of a lens issue? Can lens be calibrated for improvement?
Could the camera calibration be off to cause this behavior but for only certain lenses?
All of the above?

Or just not a steady hand and eyesight going? I don't want to discount my human error. I've read how unforgiving some lenses are especially the 75lux.

My next step is sending camera in for adjustment and maybe the lenses, but don't want to go through expense and time if someone knows better this issue.
Thank you for any ideas and recommendations.

 

[jdos2]

I'd send the camera in for adjustment. Should still be free.

Seriously.

I bought several inexpensive lenses when I got my M8 in an effort to keep cost down for a couple years.

I had to spend several hours getting the focus JUST RIGHT between 'em all- and even THEN, I had to send one back to Japan for adjustment- and I've another waiting to go back when I get the first back (it's been nearly 10 weeks now...).

You want to be SURE. The 35mm f/1.4's DoF is deep enough that if you notice problems with focus there's something going on. Since the Leica doesn't have a native "point of reference" that comes with the camera (in contrast to the Contax- where '0' degrees of rotation is infinity- a very valuable plus in the days of the ability to see the grain of any picture taken within seconds of taking it!) I'd want to be absolutely certain that the camera is set up right.

Mine wasn't.

It is now.

 

[MJones]

Camera Service

Camera Service

I'd send the camera in for adjustment. Should still be free.

Thank you for the information. Do you know if all warranty service is done in Germany? Of course I will check with Leica but I wonder if anyone has had service done in USA through Leica.

 

[JWW]

There's been lots of posts and "how tos" in LUF on this. I have a large assortment of lenses and the 75mm Lux is the most critical I have due to shallow DOF. I did a slight adjustment using the allen key adjust in the M8 and the 75mm is right on. The other lenses have a far greater DOF so that slight tweak did not affect them.

Btw be aware that the 35mm A summilux feature is a slight focus shift as you stop down which is different from back (or front) focus.

Jan

 

[Ben Z]

I can't help but think that if, as you say, the 50/1.4-ASPH is dead nuts on, that it's not the body. I had a 75/1.4 once, back in the days of film, used it on several bodies that I knew were properly adjusted, and focus was always hit or miss wide open at f/1.4 in the near range. Just the slightest leaning forward or back, that I didn't even realize I was doing, and that I couldn't detect in the rangefinder, was enough to throw eyes just enough OOF to ruin the shot. It was particularly a problem when I'd focused on the eyes and recomposed...no way to be sure the eyes were still in focus. A fast lens of that length is a whole lot more surefire on a reflex.

 

[MartinP]

I suppose half a roll with the camera on a tripod and some static "target", with some depth to see what is happening of course, is the way to double-check.

I am almost glad I have no high performance lenses . . . . almost . . . .

 

[MJones]

There's been lots of posts and "how tos" in LUF on this. I have a large assortment of lenses and the 75mm Lux is the most critical I have due to shallow DOF. I did a slight adjustment using the allen key adjust in the M8 and the 75mm is right on. The other lenses have a far greater DOF so that slight tweak did not affect them.

Btw be aware that the 35mm A summilux feature is a slight focus shift as you stop down which is different from back (or front) focus.

Jan

Thanks for the info - I found a thread on LUF using a hex wrench to adjust the infinity point and so many of the replies sounded to be about the same issue with the same lenses.

I'm going to go through some more tests with tri-pod and different objects as suggested in a couple other further replies and make sure which lenses are doing what before I do anything further. Thanks for the help.

 

[MJones]

I can't help but think that if, as you say, the 50/1.4-ASPH is dead nuts on, that it's not the body. I had a 75/1.4 once, back in the days of film, used it on several bodies that I knew were properly adjusted, and focus was always hit or miss wide open at f/1.4 in the near range. Just the slightest leaning forward or back, that I didn't even realize I was doing, and that I couldn't detect in the rangefinder, was enough to throw eyes just enough OOF to ruin the shot. It was particularly a problem when I'd focused on the eyes and recomposed...no way to be sure the eyes were still in focus. A fast lens of that length is a whole lot more surefire on a reflex.

I'm going to try some more tests to make sure what is going on and patterns. Maybe the 50 is off it's just that the 75 tolerances are higher and showing up more. I've also ordered a 1.25x magnifier to help with the 75. Thanks for the ideas.