Focus: explain to me like I’m a n00b.

[CP93]

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Definitely not a newbie, but still wasting frames due to missed focus. Been photographing since 1966, everything from 35mm (rangefinder, SLR) to MF to digital. I’ve had a greater percentage of missed shots since getting the M, than I’ve seen in ages.

Camera: M10-R.
Lenses: various Leitz, Voigtländer, and Contax.
Visoflex 20.

Doesn’t happen all the time, but I can’t put my finger on what the difference is. I know the basics: shutter speed, stance, not jabbing at the button, etc., etc.

Other than reminding myself to  “ s l o w   d o w n “  I’m not sure what I’m missing. (Response: “The focus, obviously, doofus.”)

Suggestions?

Edited January 10 by CP93

[Jeff S]

The following is for RF focusing, which is the the only way I’ve ever used an M…

Also, be sure your VF and RF windows are clean and unobstructed, and that your camera and lenses are properly calibrated (easy to check with tripod and live view). Plus, besides the vision suggestions in the linked thread, be sure your eyes are corrected for any astigmatism.

Edited January 10 by Jeff S

[erl]

1. Assess your natural vision. Do you need glasses or cataract surgery? Both can have a significant effect on your RF focussing.

2. Test the accuracy of your camera/lenses.

a. Set up a reliable 'test bench' (see pics below) and photograph it, using a tripod, at a range of distances, starting at minimum for the lens and extending out to say 20mtr. Do this at a variety of apertures. Deliberately shoot at an oblique angle of approx 45Deg. Set a target point (I taped a pencil at that point for easy sighting). Using a scale rule gives simple readout on any variation of focus.

 b. Repeat for as many lenses as you wish.

This will reliably tell you if your errors are due to equipment failure or operator error.

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[Sandokan]

+1 to above two posts. 

I had an issue with f1 lenses and my M240. I always missed focus and blamed camera until a friend nailed focus every time. I tested it as above and camera and lens were fine. 

I then decided I was useless and bought the SL. Only a few years later did I realise that after having been stable for 30 years, had got worse from -6.0 to -6.75. 

New glasses, all in focus. 

Back to M, but I still love my SL

[Chris W]

Ultra low f stop lenses are very hard to focus anyway, especially with such a narrow plane in focus.

I tend to have my lens set to f2 at the lowest, even though I have f1.4 lenses. Since the internet there has been a mad craze for shooting everything 'wide open'. If I want to nail focus in critical situations I set my f stop to f4 or f5.6.

[TomB_tx]

Another point: does it happen more with certain lenses? Some lenses are known to shift the plane of sharpest focus as they stop down enough to show at mid apertures. I have a couple that nail focus wide open but not at f4 or so. That would show if you pixel-peep at 40mp. 
As pointed out, aging vision doesn’t help. My focusing improved after cataract surgery.

[erl]

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If your camera and lens are properly adjusted and your eyes are good, focussing at f1.0 is consistently possible.

[CP93]

Thanks folks. More data required.

[jgeenen]

vor 15 Stunden schrieb CP93:

Definitely not a newbie, but still wasting frames due to missed focus. Been photographing since 1966, everything from 35mm (rangefinder, SLR) to MF to digital. I’ve had a greater percentage of missed shots since getting the M, than I’ve seen in ages.

As you said yourself - more data required.

Assuming nothing has changed, just the camera. Is it the first time having 40 Megapixels? Then the reason could be the higher magnification at 100%. If you blow up more, you will see more mistakes …

Assuming the camera‘s rangefinder is misaligned or your eyes having trouble to focus with RF - have you compared with lifeview focused shots?

or are you just too critical? I recently started to scan my old film archive. In Lightroom, so many scans look blurry. I was disappointed, never experienced this in the past to that extend… Then I printed samples at 8x10“ and compared to the original silver print. Both look equally sharp. Nothing to complain…

[evikne]

Actually, focusing a rangefinder with a large aperture shouldn't be any more difficult than with a smaller aperture. After all, what you see in the viewfinder (focus patch and angle of view) is always the same, regardless of both aperture and focal length. 

Edited January 10 by evikne

[spydrxx]

As I keep reminding myself every couple of years:

1. Check alignment/adjustment of rangefinder at minimum focus distance and infinity

2. Get eyes examined and proper glasses prescription

[charlesphoto99]

Stationary subjects, moving subjects, with or with our the Visoflex? Lots of info you are leaving out...

[pop]

1 hour ago, evikne said:

Actually, focusing a rangefinder with a large aperture shouldn't be any more difficult than with a smaller aperture. After all, what you see in the viewfinder (focus patch and angle of view) is always the same, regardless of both aperture and focal length. 

Focusing needs to be more accurate for longer focal lengths and larger apertures because of decreasing depth of field.

[M11 for me]

May I add somthing that was not said yet:

You write that you use Visoflex. I like Visoflex 2 very much as well but I do not use it for focussing. The focus I always set with the rangefinder window.

[evikne]

1 hour ago, pop said:

Focusing needs to be more accurate for longer focal lengths and larger apertures because of decreasing depth of field.

The acceptable range of perceived sharpness increases with a smaller aperture and shorter focal length, but the exact focal point is always in the same place, regardless of these factors.

The rangefinder always shows us this point, no more, no less, and in that way I feel it's always equally easy (or difficult) to use.

Edited January 10 by evikne

[pop]

2 hours ago, evikne said:

it's always equally easy (or difficult) to use

This is certainly the case. It's always equally easy to use. But that's not so useful if the picture taken with the aperture wide open will appear unacceptably blurry when it could be acceptably sharp when stopped down.

[Chris W]

Yeah, I'm with 'POP'.

I think there is a confusion about the act of focussing and the final image. Of course focussing with any aperture selected is always the same on any rangefinder camera.

But if you look at the final image taken, if you shot at f1, then the sharp part of the image taken is likely to very thin indeed. Like a headshot, the eye might be in focus but many parts of the face out of focus (nose, ears etc).

For a lot of photography, extremely low f stops are not that useful IMO. And it's become an internet trend as YouTubers say they take every picture with their lenses wide open.

I generally set my 50mm f1.4 M lens at f2 minimum, and when I'm just out and about shooting I often start with the lens set to f4, because I'm not looking for a tiny plane of in focus subject in an otherwise blurred photograph.

[evikne]

I certainly agree with you too. I'm just saying that a perfectly accurate focus is always equally easy or difficult to achieve, because the exact focal point is always in the same place. But of course, by stopping down, any inaccuracies will be camouflaged and the image will appear sharper. 

[pop]

15 minutes ago, evikne said:

I certainly agree with you too. I'm just saying that a perfectly accurate focus is always equally easy or difficult to achieve, because the exact focal point is always in the same place. But of course, by stopping down, any inaccuracies will be camouflaged and the image will appear sharper. 

... not taking into account the focus shift of certain lenses, of course.

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Hallo,

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[Ralf]

Am 10.1.2025 um 20:58 schrieb evikne:

The acceptable range of perceived sharpness increases with a smaller aperture and shorter focal length, but the exact focal point is always in the same place, regardless of these factors.

The rangefinder always shows us this point, no more, no less, and in that way I feel it's always equally easy (or difficult) to use.

+1