Newbie Leica RF focusing question

[jay83091]

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Hi Everyone,

I’ve been using my Leica M6 paired with a Summicron 35mm for about a month now, and I’ve run into some confusion regarding focusing that I hope you can help clarify.

When I set the lens to f/11 and place infinity at the upper end of the depth-of-field scale, the minimum focus distance shown is around 1.75m. My understanding is that everything between 1.75m and infinity should be within acceptable focus. However, when I look through the viewfinder at a subject clearly within this range, the two rangefinder patches in the viewfinder are not aligned. This has left me a bit puzzled, as I assumed the rangefinder alignment wouldn’t matter as long as the subject was within the focus range.

Am I misunderstanding something about how zone focusing works with a rangefinder, or could this indicate a calibration issue with my camera? Any tips or advice would be greatly appreciated.

Apologies if this is a basic question—I’m still learning the ropes!

Thank you in advance for your help.

 

 

[andybarton]

On what subject distance are the rangefinder patches unaligned?

It should coincide on a subject about 4m/12ft away. This is from my 35 Summicron.

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[UliWer]

The rangefinder (if it is properly aligned) indicates only the exact point of focus when the patches are aligned exactly. With your settings for zone focussing a subject at approximately 3m should be in exact focus and you should see this in the rangefinder. So you should try to focus a subject exactly and look if the results show the max. sharpness at your focussing point. With film this is not so easy as you see the results only some tmes later and can't reproduce them immediately. 

The early rangefinders of the M3 and M2 had small "dents" in the focussing patch where you could guess the zone focus for f/5.6 and f/16 with 50mm lenses though this wasn't really exact and so they abandoned it in the later M models.  

 

[spydrxx]

I'm sure your user manual gives a clear answer to your question. Simply put, the rangefinder focusing patch is designed to align precisely with the spot where the lens is focused. It does not show depth of field. The markings on the lens barrel for various distances are usually pretty close but not precise....therefore consider them approximations rather than exactitudes. As far as zone focusing goes...., it is a nice concept, but often results in disappointing outcomes, because it doesn't rely on the subject being in exact focus -  (the opposite of what a rangefinder is designed to do), and by giving a range of "acceptable focus" also takes into account the size of the printed image and a specified viewing distance from the picture. If you want good pictures, defined by excellent focus, use the rangefinder as it was designed. If you want snapshots based on zone focus, trade your Leica for an inexpensive fixed focus camera which relies on the depth of field using a small aperture, Those of the last century were designed to deliver "acceptably sharp" images for the masses usually within a range of 8-9 ft to infinity.

[jankap]

The rangefinder measures a distance. At that distance, your camera achieves the maximum sharpness. That is a plane, as in all cameras, but other cameras indicate with coloured dots an area of focus.

In front and at the back of the plane of maximum sharpness, the sharpness gradually decreases. The depth of scale points indicate where the sharpness decreased so far, that beyond these distances the subjects cannot be called sharp. These DOF marks were a measure for film, so take care.

My advice, measure with the rangefinder the distance to the most important subject and do not reason more. 

Edited December 23, 2024 by jankap