New to M. Question on lens

[ALScott]

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I just got M11P brand new and a used 35 lux in September.  I got the lux from a Leica dealer and it just came back from Leica for a CLA with a 1 year warranty.  I just took them on a trip out west to Yellowstone and the Tetons.  I shot mostly at f5.6-8 and set focus to infinity.  I noticed that when I was taking a landscape it appeared sometimes that even on something very far away (miles) if I backed off infinity just a touch the prism seemed to clear up a tiny bit.  Is that normal and how these lenses work?  But sometimes if something was super, super far away I could leave it all the way at infinity stop.  Bear in mind everything I am talking about was very far away.  These were sweeping landscape shots.

[250swb]

 Many people assume infinity is half a mile down the road when it really is super far away. Your best bet is to compare your feelings with the evidence in the actual photograph and see if there is a mismatch. It's difficult diagnosing without the facts so make a little test for yourself with a sequence of photos going from the lens at it's furthest range on down to something close.

[LocalHero1953]

You can use live view to compare rangefinder distance with true distance - they ought to match. Sometimes they don't for valid reasons (e.g. focus shift as a normal property of that lens) and sometimes because the rangefinder or lens are out of calibration.

Edited October 25, 2024 by LocalHero1953

[Stuart Richardson]

This is the problem with trying to do 60mp with manual focus and a focusing system from 1932. In principle, it can work very well, but it is very very demanding on the tolerances of manufacturing at this point. You should be fine setting it at infinity and f5.6 or f8 with a 35mm lens, but there is a chance that you might get slightly better results with live view or the evf setting the focus perfectly. In my experience not all Leica lenses and bodies are calibrated so perfectly for infinity. They are usually more accurate at around 1.5-3m. This makes sense because that is the zone that most people take portraits, and DOF placement is much more critical up close than at infinity. But if the question you are asking is  "can I just put the lens on infinity and not have to focus", the answer is "it depends". The best way to check is to put the camera on a tripod and focus on the moon or stars, ideally with live view. If the moon is out, it is probably fine with live view. Stars can be a bit dark depending on the ISO gain of the sensor on live view. If the lens at infinity is optimally sharp for the moon or stars, then it is in the right place.

[Maarten]

9 hours ago, ALScott said:

it appeared sometimes that even on something very far away (miles) if I backed off infinity just a touch the prism seemed to clear up a tiny bit.

This might have to do with not always looking straight through the viewfinder. Practice a bit and you will see the two subjects in the focus patch move a little, just like you describe. Once you learn to look straight through the viewfinder this effect will disappear. From your description I read your lens and camera are correctly calibrated. Enjoy your camera and lens!

[ALScott]

3 hours ago, LocalHero1953 said:

You can use live view to compare rangefinder distance with true distance - they ought to match. Sometimes they don't for valid reasons (e.g. focus shift as a normal property of that lens) and sometimes because the rangefinder or lens are out of calibration.

I assume to do this you focus from a known/measured distance with live view and compare it to distance shown on the lens, correct?

[spydrxx]

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The distance shown on the lens is actually an approximation, usually pretty reliable but not exact.

[Jeff S]

16 minutes ago, ALScott said:

I assume to do this you focus from a known/measured distance with live view and compare it to distance shown on the lens, correct?

Live view is exact; it’s what the sensor shows. If the RF matches, you’re good. 

Jeff

[LocalHero1953]

56 minutes ago, ALScott said:

I assume to do this you focus from a known/measured distance with live view and compare it to distance shown on the lens, correct?

Not usually* - the absolute distance is not important, it's just whether liveview shows you the same point in focus as your rangefinder (liveview is always right, because that is identical to your final taken image). I focus on Point A using the rangefinder, and if it is out of focus in liveview, then EITHER the rangefinder is miscalibrated OR there is focus shift involved OR (less commonly) the lens is miscalibrated**.

If all your other lenses show correct focus against the rangefinder then the problem lies in the lens. If they all show the same mismatch, then the problem lies in the rangefinder.

Edit. This facility to use liveview was one of the massive gains of moving away from the CCD M9 to CMOS M240 (and M10, M11) - no more uncertainty about rangefinder calibration.

 

* When I had a digital M, I did actually use a tape measure laid up the garden path so I could see by exactly how much the rangefinder and liveview differed. For closer distances I made a wooden frame with a printed target pasted to it (at 45 degrees to the vertical, with the scale printed stretched by 1.41414 🙂).

** This only happened to me once: an Apo-Summicron-M 90 didn't focus correctly to infinity - Leica recalibrated it. I had bodies recalibrated twice (I would attempt it myself now, if I had one), and I had one lens with a lot of focus shift: Zeiss C-Sonnar-M 50mm f/1.5, which is recognised for it. 

Edited October 25, 2024 by LocalHero1953

[ALScott]

29 minutes ago, Jeff S said:

Live view is exact; it’s what the sensor shows. If the RF matches, you’re good. 

Jeff

 I have a harder time determining focus with live view than RF.  How do you tell using live view if something is in focus?  Just by appearance or focus peaking?  There isn't a focus indicator like SL3 or Q3  or any other AF camera is there?  I started with manual cameras but first RF and of course first one with Live View.  

Forgive me as this is all new.  I need to take some sort of M class.  I am not having trouble using it, I love it, but I do like to know everything about any equipment I have, camera or not.

[Vanillasludge]

Sooo…there is always a grey area with precise rangefinder focusing.  In addition to the variables of lens and camera calibration, there are optical characteristics unique to each lens design.  

Some lenses shift focus as their aperture changes.   Some exhibit field curvature that change the outer zone focus point.  

In the end, if your near and distant images look sharp, you can be satisfied with the calibration.   

[TomB_tx]

15 minutes ago, ALScott said:

 I have a harder time determining focus with live view than RF.  How do you tell using live view if something is in focus?  Just by appearance or focus peaking?  There isn't a focus indicator like SL3 or Q3  or any other AF camera is there?  I started with manual cameras but first RF and of course first one with Live View.  

Forgive me as this is all new.  I need to take some sort of M class.  I am not having trouble using it, I love it, but I do like to know everything about any equipment I have, camera or not.

Good point - I've found focus-peaking not especially accurate. I do better just judging the sharpness as I used to on a ground-glass screen. But using M cameras for 55 years I've come to trust the RF - and it is much faster.

[LocalHero1953]

16 minutes ago, ALScott said:

 I have a harder time determining focus with live view than RF.  How do you tell using live view if something is in focus?  Just by appearance or focus peaking?  There isn't a focus indicator like SL3 or Q3  or any other AF camera is there?  I started with manual cameras but first RF and of course first one with Live View.  

Forgive me as this is all new.  I need to take some sort of M class.  I am not having trouble using it, I love it, but I do like to know everything about any equipment I have, camera or not.

We've all been through it! You need sharp eyes and a wide open lens. One advantage of using a measuring tape or printed scale is that you can see if you can distinguish the millimetre or centimetre scale marks, especially as you zoom in in liveview. It sometimes takes a bit of focusing back and forth before you're sure you've actually focussed on the point you intended to.

They didn't have focus peaking with the M240 IIRC so it wasn't an option.

[LocalHero1953]

I should have said: it is not an absolute requirement to use liveview for focus checking. You can take an image, download it, and zoom in at max resolution to see exactly if your rangefinder focus point is in focus or not. It's what we had to do with the M9. It's slow, but certain.

[Jeff S]

It almost goes without saying, but one should first ensure that their eyesight is well corrected.

Jeff

[pedaes]

11 hours ago, ALScott said:

I shot mostly at f5.6-8 and set focus to infinity.

You will get maximum 'depth of field' if you set hyperfocal focusing by setting the Infinity mark against the apperture one below (for safety)  the apperture you are using. Say 5.6 if using f8/4 if using f5.6.

[ALScott]

52 minutes ago, Jeff S said:

It almost goes without saying, but one should first ensure that their eyesight is well corrected.

Jeff

Well.... that is a solid point.  I do use the diopter on the SL3 and wondered if I shouldn't order one for the M11P.  It's tough to answer as on occasion I do use readers of +1.00 for really close, small stuff but not the computer, etc.

[lct]

I would use focus magnification in LV mode, best way to check if the RF is well calibrated IMO. Otherwise i would use the infinity symbol of lenses for infinity only. I mean the moon, remote mountains, etc. Nothing less than 1,000m i would say but you'll find different comments on the web about that.

Edited October 25, 2024 by lct

[streetrattakesphotos]

Actually, even with the moon. Don't know if the M11-P was the OP's first camera, but with the telephoto RF 100-500mm for my R5, the moon is not at infinity. I have M lenses that don't do very much of this, and they're the ones without much throw at that end of the focus ring, so that it's fairly hard to tell.

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[Jeff S]

1 hour ago, ALScott said:

Well.... that is a solid point.  I do use the diopter on the SL3 and wondered if I shouldn't order one for the M11P.  It's tough to answer as on occasion I do use readers of +1.00 for really close, small stuff but not the computer, etc.

First thing is a good eye exam to assess not just distance, but astigmatism, and correct for each as needed. I use glasses to correct for both, as I don’t want to be taking my glasses on and off when the VF isn’t to my eye.

But as I aged, I found that I also needed a minor (+.5) diopter correction, in addition to my glasses. To figure that out, since I’m not near a dealer, I took my M to a local optician and experimented with their free trial diopters.  I then ordered from my dealer.

Jeff