Horizontal rangefinder adjustment (M11)..

[AveryWagg]

When using the 50mm Summicron lens (v5) recently, I noticed that the camera was out of rangefinder calibration a bit (at infinity). That seemed odd as I had just finished setting the camera's calibration using the CV-90mm lens a few days ago. Well, it turns out the RF calibration is a pinch different for each lens. Most of the lenses become well aligned when I use the 50mm to adjust the camera's calibration. Even my old Tele-Elmart-90mm was bang-on. However, once set, the new CV-90 becomes the odd man out. It'll now goes past infinity a bit. Not by a lot, but it is noticeable.

My question is; Is there some kind of adjustment I can do to the new CV-90 lens to make it align like the others?

..Avery

 

[Godfrey]

When using the 50mm Summicron lens (v5) recently, I noticed that the camera was out of rangefinder calibration a bit (at infinity). That seemed odd as I had just finished setting the camera's calibration using the CV-90mm lens a few days ago. Well, it turns out the RF calibration is a pinch different for each lens. Most of the lenses become well aligned when I use the 50mm to adjust the camera's calibration. Even my old Tele-Elmart-90mm was bang-on. However, once set, the new CV-90 becomes the odd man out. It'll now goes past infinity a bit. Not by a lot, but it is noticeable.

My question is; Is there some kind of adjustment I can do to the new CV-90 lens to make it align like the others?

..Avery

Sounds to me like the RF actuating cam in the CV-90 is slightly off from its proper position. I don't have one of those lenses, would have to see how it's put together to see how to effect an adjustment. You might need to rig up some kind of optical test bench to do it.

G

 

[Bill Blackwell]

Interesting you bring this up as my M11-P's RF doesn't quite line-up at infinity with any lens. The mis-alignment is so slight it's not worth it for me to have it fixed. The only thing I would know to do in your case would be to either send the lens and camera to a repairperson and have him or her adjust the lens to the camera or try adjusting it yourself. I believe all you need to do is add or memove shims from behind the lens mount.

For me, assuming you're not having any focusing issues in your images, I'd just leave it.

 

[whagen]

To adjust the M11 at infinity is vers simple. All you need is a 2mm allen key.

 

[whagen]

If you have a missalignment at infinity with all your lenses its probably the camera. You can simply adjust infinity on your M11. I would do the adjustment. If infinity is not correct, you also have a misalignment at all other distances. The only thing you need is a 2mm allen key. The roller inside the body is mounted excentrically. Take a target 2 or 3 km away to check infinity with the lens. Take off the lens and adjust the roller with the allen key carefully in very small steps. If infinity is correct with the lens, crosscheck the close distance.
If it is the lens which needs to be adjusted, you should consult a repairman as there needs to be added or removed shims. This you can not do yourself.

 

[peterm1]

I wonder if it matters much. If it is only with one lens, then as others point out the problem is most likely with the lens itself (or a slight combination of both the lens and the camera). But in any event, I find that in practice, 99% of infinity photos are shot stopped down and the extra DOF conferred by this "covers all sins". If this is so with your lens, you may not need to worry as a matter of practical necessity. Of course, if it focuses beyond infinity, as DOF extends more beyond rather than in front of the point of focus, the "wriggle room" is less and you may need to make an adjustment. But based on what you have said I suspect this is best made to the lens not the camera (as adjusting the camera to the quirks of THIS lens may throw the focus of other lenses off.)

 

[whagen]

I wonder if it matters much. If it is only with one lens, then as others point out the problem is most likely with the lens itself (or a slight combination of both the lens and the camera). But in any event, I find that in practice, 99% of infinity photos are shot stopped down and the extra DOF conferred by this "covers all sins". If this is so with your lens, you may not need to worry as a matter of practical necessity. Of course, if it focuses beyond infinity, as DOF extends more beyond rather than in front of the point of focus, the "wriggle room" is less and you may need to make an adjustment. But based on what you have said I suspect this is best made to the lens not the camera (as adjusting the camera to the quirks of THIS lens may throw the focus of other lenses off.)

First of all you have to find out, if the camera or the lens is missaligned. If only one lens does not reach infinity it is probably the lens. If all lenses show the same effect it is probably the camera. The easiest way is to check the camera with a lens which is perfectly adjusted to infinity. As said to just the camera is very easy and takes 5 minutes.
The rangefinder is generally adjusted to infinity and if so it will fit also at close focus distance even with a Noctilux. At infinity the DOF might work but with open aperture at close focus distance you will get a front- or back focus of some cm.

 

[AveryWagg]

I wonder if it matters much. If it is only with one lens, then as others point out the problem is most likely with the lens itself (or a slight combination of both the lens and the camera). But in any event, I find that in practice, 99% of infinity photos are shot stopped down and the extra DOF conferred by this "covers all sins".

I think you're right. I'll just shoot the CV-90 at F4, or tighter and let it go at that. Thanks!

..Avery

 

[brusby]

Make sure to check the rangefinder focus against magnified live view. A lens and camera both correctly calibrated should agree at all distances.

It helps if you have at least one lens that is known to be correct so you can use that as a baseline to check your camera's rangefinder accuracy and then to compare your other lenses to it. Maybe even go to a Leica store and see if you can use one of their lenses that are known to be correct to do a quick check of your camera's rangefinder accuracy.

Once the rangefinder is known to be accurate, I'd proceed to check all my other lenses by focusing with the rangefinder and then checking in live view, to see which seem to be calibrated correctly and which don't.

 

[Rob-F]

For adjusting the camera, I use one or another of several TV station transmitter towers that are anywhere from about 3 miles to 6 or 7 miles away, all visible from my office window. I see little or no difference as to which one I use, but of course it makes sense to use the one furthest away, as long as it's a clear day. I like the towers because the vertical steel structural members appear very thin at that distance, making it very easy to tell if they are in perfect coincidence. Of course, some prefer to use the moon. No argument as to the moon being a good infinity target (well, Venus is better still); but my TV towers are far enough, I believe. I get to do the work indoors, and I need the window sill as a work surface!

 

[WoodallP]

For adjusting the camera, I use one or another of several TV station transmitter towers that are anywhere from about 3 miles to 6 or 7 miles away, all visible from my office window. I see little or no difference as to which one I use, but of course it makes sense to use the one furthest away, as long as it's a clear day. I like the towers because the vertical steel structural members appear very thin at that distance, making it very easy to tell if they are in perfect coincidence. Of course, some prefer to use the moon. No argument as to the moon being a good infinity target (well, Venus is better still); but my TV towers are far enough, I believe. I get to do the work indoors, and I need the window sill as a work surface!

I am very unlucky (in one sense), I used to be able to see the Eiffel tower through my window but it was too damn close 😂. I now live the other side of Paris but facing the opposite direction. The only way I can see it is standing in the middle of a busy road!

I now have a block of flats at about a mile, not perfect I know but probably useable.

 

[Rob-F]

I am very unlucky (in one sense), I used to be able to see the Eiffel tower through my window but it was too damn close 😂. I now live the other side of Paris but facing the opposite direction. The only way I can see it is standing in the middle of a busy road!

I now have a block of flats at about a mile, not perfect I know but probably useable.

Well, living in Paris can't be too unlucky, though!

 

[peterm1]

I am very unlucky (in one sense), I used to be able to see the Eiffel tower through my window but it was too damn close 😂. I now live the other side of Paris but facing the opposite direction. The only way I can see it is standing in the middle of a busy road!

I now have a block of flats at about a mile, not perfect I know but probably useable.

While speaking of the Eiffel Tower there is a lovely story of someone (I forget exactly who) who hated it for aesthetic reasons. But even so, he used to dine regularly at a restaurant located in the tower. When asked why he did this in the circumstances, he replied it was because the view from the restaurant was such that it was the only place in the vicinity where he was not obliged to look at the tower while he was dining. 🙂 🤣

 

[Freakscene]

While speaking of the Eiffel Tower there is a lovely story of someone (I forget exactly who) who hated it. But he used to dine regularly at a restaurant in the tower. When asked why he did this in the circumstances he replied it was because the view from the restaurant was such that it was the only place where he was not obliged to look at it. 🙂 🤣

It was the British writer William Morris Quote Origin: This Is the Only Place Where I Can Avoid Seeing the Damned Thing – Quote Investigator®

 

[peterm1]

It was the British writer William Morris Quote Origin: This Is the Only Place Where I Can Avoid Seeing the Damned Thing – Quote Investigator®

Was he also the same William Morris who was a leader of the Arts and Craft movement? Perhaps he got the name wrong - thinking it was the "Awful Tower". Not that I thinks so myself. 😳

 

[Freakscene]

Was he also the same William Morris who was a leader of the Arts and Craft movement? Perhaps he got the name wrong - thinking it was the "Awful Tower". Not that I thinks so myself. 😳

One and the same. William Morris - Wikipedia

 

[peterm1]

BTW testing close focus is easy enough too. Though a little long to explain when written.

I had to do this with my M8. I took a 2 metre long piece of planed wood, marked a central focusing mark (the aiming point) then also marked in1cm increments both in front and behind for about 45cm on either side. I used a medium Texta for this. I then made two little signs on paper - one said "by rangefinder" and the other said "by measured distance". In this instance the measured distance would always be 3 metres (see below). As I shot images at various f stops I would also mark which f stop I was using for that shot on the paper as well, I then placed one or other of these papers in each shot so I knew these key variable when I later reviewed the images on my PC. I set my camera up on a tripod and laid the wooden measuring stick on the ground such that the central point (the aiming point) was an EXACT measured distance from the plane of the sensor on the camera. to the central aiming point. I used 3 metres as the measured distance to the target because the lens I was using (a 50mm lens) had the 3 metre marked on it. Also 3 metres is a reasonable portrait distance and this distance is relevant as I would be shooting at this distance quite a bit

I then proceeded to shoot the lens, starting with a fully open aperture using, first using the rangefinder to aim at the central point, then another shot would be taken by zone focusing set at 3 metres. On each occasion the relevant paper sign was placed on the ground alongside the aimpoint on the wooden rod before taking the test shot. After this I repeated the same at various f stops - f2, f2.8, f4, f5.6 to see how the focus point moved due to focus shift or due to miscalibration. At some point the depth of field from stopping down tended to correct any areas.

From there it was a simple matter to load the resulting images onto my computer and examine how close to intended point of focus the shots were (and whether it was ahead of or behind the target.) This gave me a reasonable idea if the rangefinder was accurate and if not, how far out it was at each f stop. The shots that were measured by distance would, if unfocused, suggest the problem was one of lens calibration / shimming. A soft result with using measured distance suggest that the camera rangefinder was out. This is usually the culprit but doing this kind of test confirms it and gives a guide as to how much adjustment was needed for the rangefinder.

 

[mdarnton]

First world problems (that's a joke, folks.) But digital problem, for sure. The RF mechanism was designed 100 years ago for film. It wasn't intended to focus for pixel peepers, nor could it ever compensate for focus shifts and still can't, even in theory, and the results were "good enough" on average on film. You could set it to be theoretically right, but few lenses actually worked just that way. Sure, lens cam manufacture is one part of it and that problem has been there since the start but relatively unimportant in the actual use the camera got, since just about no one was using Leicas to shoot the high-res landscapes where it shows up the most.

Now that we can zoom in to 100% we can see all of the flaws in the concept. When I go back and digitalize my film I see all sorts of theoretical problems that weren't problems then in real prints, but now is different. But I think asking an inherently flawed relic to do the job on a modern digital camera is asking too much of the technology. Wish on.

That's why I've never had the desire for a digital RF camera and use all my classical lenses on a Nikon Z5, which can actually focus them accurately, at aperture, regardless of all their real problems.