M8 and Noctilux

[Olsen]

I have found out that my M8 is back focusing with about 10 cm at about 2 meters focusing distance when focusing with the very tricky Noctilux with it's tiny DOF. Still, the viewfinder is perfectly alligned at infinity. How could this be?

 

[StuartR]

The rangefinder may be perfectly aligned, but that does not mean that the lens is perfectly matched to the body. For absolute precision, the nocitlux should be individually calibrated to the M body that you are going to use it on.

The other possible issue is focus shift. The noctilux does have a small focus shift depending on aperture.

 

[andrewch]

I had a similar problem with my 35mm pre-asph summilux that front focus by a few inches at 2m. One technician that I sent the lens to kept telling me that he could see nothing wrong with the ground glass on the back of his M6, even though I showed him a 100% view of pictures taken wide-open at 1m. I guessed it was just too much hassle for him to fix it. Fortunately I found a good technician who ground down the focusing cam for me. He would grind down a thread, check the focus on my R-D1, and then ground another one until the focus was perfect. He made me a very happy man.

 

[Olsen]

The rangefinder may be perfectly aligned, but that does not mean that the lens is perfectly matched to the body. For absolute precision, the nocitlux should be individually calibrated to the M body that you are going to use it on.

The other possible issue is focus shift. The noctilux does have a small focus shift depending on aperture.

I called the norwegian importer, Lars Farnes, today and presented the problem. They said that 'something might be wrong with the viewfinder even though it is correct at infitity'. I have two Leica lenses that needs to be coded and wondered if I should turn in the camera as well. He said that all lense coding - and adjusting - all old lenses will be adjusted 'finer than they have ever been', is performed at the factory in Solms -and so is waranty inspections of M8, and will take 5 to 6 weeks....

Now I am wondering if I should send in the camera and the lenses now - or wait until something even worse goes wrong with the camera. Like a freeze, or something. Or is it likely that the fine tuning of the Noctilux is enough adjustment. Any opinions?

 

[Olsen]

I have done some furhter tests. It is the Noctilux that is causing the back focusing! Not the M8. The M8 is totally in line with the viewfinder when I use my Zeiss Ikon Planar 2/50.

 

[Olsen]

Æhum!

Some further test results: It seems to that removing the UV filter on the Noctilux (voila!) improves it's accuracy dramatically... It is now down to a few cm which could well be the tollerances of my own eye sight....

I make the conclusion that 'nothing is wrong with the M8', it is staying home while my two old (well...) Leica lenses will be sent to the gass chambers, - æhu, Germany. (Don't mention the war!)

 

[furcafe]

I agree w/Stuart. There is enough variation between M bodies & lenses that even if each is individually within specifications, a given camera-lens combination can be off. An additional factor is that the margin for focus error w/a digital sensor is apparently less than w/film (because sensors are thinner than film). FWIW, I had my M8's focusing fixed because, among other problems, I was getting backfocusing w/all of my Leica lenses (LTM & M). Since I got it back, I've noticed that there is still a small, but noticeable backfocus w/most of my modern lenses that are 50mm & longer; for whatever reason, wides & vintage 50mm+ lenses are fine. Since I have more film bodies than digital bodies & experience no backfocusing w/any of lenses when they're mounted on the film bodies, for now I'm going to simply make a slight focus adjustment when using certain lenses on the M8.

The rangefinder may be perfectly aligned, but that does not mean that the lens is perfectly matched to the body. For absolute precision, the nocitlux should be individually calibrated to the M body that you are going to use it on.

The other possible issue is focus shift. The noctilux does have a small focus shift depending on aperture.

 

[StuartR]

Actually, in many ways I think it is a testament to the sharpness of the M8 that these minute errors show up at all...

 

[jaap]

Æhum!

Some further test results: It seems to that removing the UV filter on the Noctilux (voila!) improves it's accuracy dramatically... It is now down to a few cm which could well be the tollerances of my own eye sight....

I make the conclusion that 'nothing is wrong with the M8', it is staying home while my two old (well...) Leica lenses will be sent to the gass chambers, - æhu, Germany. (Don't mention the war!)

THIS ISN'T FUNNY AT ALL !

 

[Olsen]

I agree w/Stuart. There is enough variation between M bodies & lenses that even if each is individually within specifications, a given camera-lens combination can be off. An additional factor is that the margin for focus error w/a digital sensor is apparently less than w/film (because sensors are thinner than film). FWIW, I had my M8's focusing fixed because, among other problems, I was getting backfocusing w/all of my Leica lenses (LTM & M). Since I got it back, I've noticed that there is still a small, but noticeable backfocus w/most of my modern lenses that are 50mm & longer; for whatever reason, wides & vintage 50mm+ lenses are fine. Since I have more film bodies than digital bodies & experience no backfocusing w/any of lenses when they're mounted on the film bodies, for now I'm going to simply make a slight focus adjustment when using certain lenses on the M8.

Well. Mine was mostly backfocusing with the Noctilux with it's UV filter on. Markedly less with the filter off, but the tendense is still there. With the Zeiss Ikon my M8 is dead on.

The Farnes rep emphesized that digital cameras demand smaller focusing tolleranses and that the coding - was not just coding, but changing of the bayonett e and ditto very accurate focusing adjustment. Why this is so, I don't know.

I have a Canon EF 50 mm 1,0L which is also demanding to focus. You can forget AF because only a few cm off a.e. the eyes and the picture looks soft. You have to rely on a very good eyesight to be sure that you are dead on.