M2 Infinity Setting

[ColColt]

I never paid much attention to it after I had to tweak my vertical alignment on the M2 but noticed late tonight, as there was a clear sky and moon, that the infinity setting is a little off. Setting the lens to infinity i found it was better in focus just shy of the infinity setting. I had to back off just a mite. Is this discernible in photos in any way and if so if I mess with trying to correct it will it affect the vertical I just corrected?

 

[BetterSense]

It is probably not significant. In most pictorial applications, it is not worth tuning in perfect infinity focus. It is far more important that intermediate and close focus be accurate.

 

[Newt_on_Swings]

Did you also try it with a different lens? Sometimes lenses can be slightly off as well. Easiest way is to lock the shutter open and use a piece of scotch tape across the film plane and use a loupe to check if your focusing matches the lens markings and rangefinder.

 

[mnemosyne]

AFAIK, if done properly, the adjustment of the vertical should not have any influence on the horizontal adjustment.

It is not uncommon that the horizontal adjustment is slightly off in some M cameras with certain lenses. Even if I had this with all my lenses, I would not let it bother me UNLESS I notice that the RF is off at medium or short distance, which is not necessarily the case.

As long as your rangefinder works properly wide open at short and medium distances (easy to find out when you put your camera on a tripod and do a series of test pictures), be happy and do not touch the mechanism. The minimal horizontal offset at infinity might be annoying, but is mostly irrelevant for pratical photography unless you use long lenses at wide apertures and long distances a lot. If you shoot at infinity, simply set the lens at infinity. When you start to tamper around with the horizontal adjustment, you stand to loose much more than you could possibly gain, because there is a risk that, when not done properly, adjusting the infinity setting to perfect matching will throw the rest of the system out of whack. If you notice missed focus shots on a regular basis and have the feeling that it is not user error, test your rangefinder carefully (tripod!) and if you find any irregularities please have it ajdustd by a competent repair person.

There are factory manuals for the M2 available on the internet that explain the adjustment procedure of the Leica rangefinder mechanism in all its glory. I recommend you have a lookt at it just to understand that contrary to Internet lore this is a rather complex and demanding procedure (if done properly). You will ask yourself why Leica wrote pages of text describing adjustment and testing, when all the Internet experts claim that anyone with a screwdriver can do the job during a coffee break! You will also learn that it is possible to mess up the mechanism in such a way that the camera has to be disassembled to have the RF re-adjusted from scratch. And, one might add --- this is not written in the repair manual, but taken from a recent post by some very unhappy fellow in a different forum --- it is indeed possible to screw up the job so thoroughly that even Leica factory service has to determine the RF unrepairable and replace the whole unit ...

 

[Xmas]

I never paid much attention to it after I had to tweak my vertical alignment on the M2 but noticed late tonight, as there was a clear sky and moon, that the infinity setting is a little off. Setting the lens to infinity i found it was better in focus just shy of the infinity setting. I had to back off just a mite. Is this discernible in photos in any way and if so if I mess with trying to correct it will it affect the vertical I just corrected?

There are two adjustments for horizontal and they can interact with the vertical.

The two adjustments have only one position where the rangefinder is both accurate at each of 1m, 10m and infinity and has minimal error at intermediate points.

If the vertical is off normally the horizontal is off.

I'd not recommend you think about DIY.

The other questions are the register plate distance from the film plane and each lens heliciod.

The only easy way is to use a laser pointer and a computer program...

If you have a /0.95 Leica want them both back, they have been doing that from the /1 in '79.

 

[mdarnton]

Adjusting horizontal for simple infinity is not that hard. I've been doing it for over 40 years and never messed up a camera. If you habitually break things. . . . maybe. The correct way to go about it is to assume that everything else is right unless you have indications otherwise, not get the book and try to fix everything, broken or not.

However, if the photos are in pretty good focus, the adjustment is right, and you shouldn't mess with anything. For years I've been pondering Leica family focus issues, and recently come to the realization that there is no way to get everything absolutely right in all situations, and that, for instance different lenses or Canon vs Leica treated the more flexible issues, focus shift with different apertures being the main one, differently. When I came to that realization, a lot of things fell into place. So it doesn't do much good to get compulsive about it.

 

[Xmas]

Adjusting horizontal for simple infinity is not that hard. I've been doing it for over 40 years and never messed up a camera. If you habitually break things. . . . maybe. The correct way to go about it is to assume that everything else is right unless you have indications otherwise, not get the book and try to fix everything, broken or not.

However, if the photos are in pretty good focus, the adjustment is right, and you shouldn't mess with anything. For years I've been pondering Leica family focus issues, and recently come to the realization that there is no way to get everything absolutely right in all situations, and that, for instance different lenses or Canon vs Leica treated the more flexible issues, focus shift with different apertures being the main one, differently. When I came to that realization, a lot of things fell into place. So it doesn't do much good to get compulsive about it.

The only point about testing on the moon is it tells you there may be a problem at close in where you need the rangefinder.
The M is not like a SLR where you need to set it at infinity and job done...
If you want it quick and dirty you set up the rangefinder at 5 meter where you need eye lashes sharp.
If you set either of the adjusters at infinity you have just 'fixed' five meter good.

 

[ColColt]

When I saw the focus was a bit beyond the moon I couldn't help think of an old movie, "Toy Story". Even though a kid movie I enjoyed it way back when with my step grand daughter. The line from Buzz Lightyear, "To Infinity, and beyond", made me think of the focus going past the moon.

I think I'll leave well enough alone. I got some sharp pictures yesterday while doing some street shooting at a variety of distances and some of the close up shots, 10-20 feet, were more than acceptable with the 50 and 90 lens I was using...a good example was this shot from about 10-15 feet with the 90 f2.8 at f4.

Dntwn+012a by David Fincher, on Flickr