Help required re: Mamiya 6 infinity focus

[Canon Alberic]

Hi everyone

I've just acquired a Mamiya 6 body with all three lenses. (It's my first rangefinder so I apologise if this is an obvious question!)

With any of the three lenses mounted, I cannot get the rangefinder patch images to align horizontally at infinity focus. For relatively near objects with each lens (usually less than 30 ft), I can focus and align the patch images perfectly well. However, for objects beyond the focus range (ie. at the infinity symbol of each lens) I cannot get the patches to align. This is the case for objects 500ft away or several km away - I have tested this with antennae several miles away. To clarify, the patches never meet (ie. they do not go 'beyond' infinity).

So, does the M6 body rangefinder require horizontal adjustment, or am I missing something? Hope this makes sense.

Thanks in advance, and best regards,

Douglas

 

[john_s]

It's probably close enough, particularly since the lens apertures are not particularly wide. I have stopped worrying about very small discrepancies. It's a matter of degree.

A lens at its infinity stop will be focused on infinity. The problem might be noticeable at closer distances. I would be inclined to take some critical test photos at a couple of distances, say 2m and 5m, using the rangefinder, and see if there's inaccurate focus.

It is possible to adjust the rangefinder yourself. Instructions are on this site somewhere, but it is possible to do some damage if you're not careful.

 

[Canon Alberic]

Thanks, John, that makes sense and I'd rather not starting adjusting the body, if at all possible, so I think I'll leave well alone until I get my first rolls back from the lab.

 

[historicist]

Just a thought, but on mine the RF patch is quite sensitive to the position of your eye - if it's a bit off centre the patches don't quite align.

 

[Canon Alberic]

Just a thought, but on mine the RF patch is quite sensitive to the position of your eye - if it's a bit off centre the patches don't quite align.

Absolutely, same with mine too. With my eye "centred", I still cannot get the patches to align. I assume that you can - have you had to adjust your body at all?

 

[Matus]

Check it out again an if it is not a wrong position of the eye than you need to have the rangefinder of the camera adjusted. Do not get fooled by the relatively "slow" lenses. In fact in particular with the 150 - if you want to be able to use the lens close to wide open, your rangefinder needs to work correctly and the lens needs to match it.

So - check it out and if necessary send the camera for a service - together with the 150 lens so you can be sure you will get the focus right.

Remember - if the RF patch does not align for infinity it means it is off through out the whole focusing range, not just infinity.

 

[Canon Alberic]

Many thanks, Matus. The issue is consistent with each of the three lenses, so it seems I do need to have the camera's RF adjusted. Can anyone recommend a service place in London/UK for the Mamiya?

 

[historicist]

All I can say is that I got mine cheap in Japan, and felt that it was slightly off at infinity. It didn't cause any problems in practice, partly because the dof at infinity is massive and partly because infinity rarely forms a part of any photo I make. Whether it'd be a problem for more critical users I can't say.

I took it to Aperture UK in Museum Street (who btw would be at least one place in the UK that can service the Mamiya 6) to have a general service and told them about this and they seemed to think there was nothing wrong with it, and that it was to do with my eye position - given that they stood to make extra money from a RF alignment, I'm inclined to trust them.

With my current (different, very rough) Mamiya 6 the RF patch often seens to be a tiny bit off vertically or horizontally, and moving my eye changes how much off it is, so I'm inclined to think that the finder is quite sensitive to eye position (never had the same issue with a Leica). It's never been a problem in practice, my pictures have always come out sharp, so I've never bothered to get someone look at it.

Again I'm not a big infinity shooter and mine might be different from yours...

 

[Canon Alberic]

All I can say is that I got mine cheap in Japan, and felt that it was slightly off at infinity. It didn't cause any problems in practice, partly because the dof at infinity is massive and partly because infinity rarely forms a part of any photo I make. Whether it'd be a problem for more critical users I can't say.

I took it to Aperture UK in Museum Street (who btw would be at least one place in the UK that can service the Mamiya 6) to have a general service and told them about this and they seemed to think there was nothing wrong with it, and that it was to do with my eye position - given that they stood to make extra money from a RF alignment, I'm inclined to trust them.

With my current (different, very rough) Mamiya 6 the RF patch often seens to be a tiny bit off vertically or horizontally, and moving my eye changes how much off it is, so I'm inclined to think that the finder is quite sensitive to eye position (never had the same issue with a Leica). It's never been a problem in practice, my pictures have always come out sharp, so I've never bothered to get someone look at it.

Again I'm not a big infinity shooter and mine might be different from yours...

That's really useful, thank you.

 

[Matus]

Douglas, I would say - expose one or better two rolls of some color slide film (be sure to read around here how to use the built-in lightmeter - it can be easily fooled by bright sky what results in underexposed images) with the 150 and 75 lenses (50 is the least sensitive to rangefinder problems) - wide open if possible - and note in a notebook for each image where the focus was. Choose static subjects with some distinct, easy to focus on features (fences, bicycles, street lamps, etc ...). The lenses are scary sharp even wide open - it is easy to notice wrong focus afterwards.

Once you get the films back from the lab - put them on a light table and take 8x loupe to check for focus. Be prepared for some miss-focused images, it takes some getting used to. But if you end up with images which show some systematical focus error (either closer or farther than intended), then you need to have the camera checked. To check infinity focus you need objects at least 1km away.

________
Actually - I did exactly what I wrote above when I bough the Mamiya 6 (in August) - mainly to learn how to use the light meter and to see that everything works as it should. This were the best invested 2 rolls of film - afterwards I knew quite well how to compensate for different light conditions and most of my slides from following vacation were correctly exposed.

 

[dtcls100]

I adjusted my 4 Mamiya 6 bodies by making sure a full moon was precisely in focus at infinity using the 150mm lens. The rangefinder of the Mamiya 6 is very sensitive. Even something a mile away should be very slightly out of focus at infinity. The rangefinder focus adjustments take a long time to get right and you have to proceed VERY SLOWLY in the tiniest increments to get it just right. Now all of the bodies (using the same lenses) essentially match up at various distances and with a tape measure.

Also, the image will not appear to be sharp if the vertical adjustment is very slightly off. The rangefinder adjustments in the body are very subtle -- the slightest adjustment can make a noticeable difference.

 

[Canon Alberic]

Thanks again everyone, you've been really helpful. I tweaked the horizontal adjustment screw around 1/6th of its circumference anticlockwise and distant objects are now lining up perfectly.