Focus: explain to me like I’m a n00b.

[pgk]

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On 1/10/2025 at 7:58 PM, evikne said:

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.

Not exactly. The rangefinder always shows us a point of focus within the tolerance of the rangefinder (based on its separation and mechincal accuracy) rather than as you put it 'exact'. This will be consistent, but within a tolerance. The problem being that faster and longer lenses may require a higher degree of precision than slower and shorter lenses and beyond this any discrepancy become noticable. So any difficulty (lack of contrast, lack of precise subject matter to align using the rangefinder, user's eyesight and perception of coincidence) can soon become apparent using lenses which are faster and longer and the tolerance is insufficient. Which is why faster and longer lenses are apparently more difficult to precisely focus than slower and shorter ones  - they require better visual conditions in order to operate well.

Rangefinders work exceptionally well within their design parameters but become tricky if used outside them - and these parameters should include light and contrast levels as well as the user's eyesight which may need correcting to ensure that the coincident image is correctly focussed too. As I have stated before, rangefinders work best (often better than other systems) with wide-angle lenses. They can compete with standard and short telephotos and some fast lenses, but start to struggle with very fast and longer lenses. Its simply the nature of RF equipment.

[adan]

This is your problem.

On 1/9/2025 at 6:15 PM, CP93 said:

Visoflex 20.

It is a focusing screen that requires you to distinguish "sharp" from "kinda sharp" from "maybe blurry" to "blurry" with the naked eye.

Take it off and focus with the rangefinder, which is binary - the two RF images are aligned (focused) or they are not aligned (unfocused). Much easier for the eye and brain to detect accurately. Especially with the shorter focal lengths of the M system (50mm or wider).

[Alberti]

I agree with  Sandokan. Glasses might not keep the right prescription after several years.

& yes I liked multifocals a lot, but when the vision changes a slight bit / or when the glasses themselves start to sag a bit,

- - then the good spot is also off, in my experience (I blamed it on that) and the ease of alignment changes . . .

So I have bi-focals; that is, a part of the glass is infinity (and very pure just that); and the bottom is for reading a newspaper/laptop screen at 35cm. Zeiss used to make them; now I have some Israeli glass. I have a separate pair of glasses for the big computer screen.

But really: all M-range shooters with glasses need to have the Digivid or  DUOVID, the specially developed Leica glass (my father used to have it even for his Voigtländer):

Quote

DIGIVID® PHOTO is perfect for working on the camera. It is equipped with two viewing areas: One area that ensures a distortion-free view through the viewfinder and allows you to see clearly into the distance. And an area for checking your recordings on the display and the camera settings.

What can be better better really better than a pair of Leica Digivid  red-dot glasses?

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Simply register for free here – We are always happy to welcome new members!

and also note that they got a  .  .  .   "Red Dot Award for Product Design 2020" for  prescription/sun glasses.

You just can't have enough red dots.

Edited January 12 by Alberti

[CP93]

On 1/12/2025 at 10:09 AM, adan said:

This is your problem.

It is a focusing screen that requires you to distinguish "sharp" from "kinda sharp" from "maybe blurry" to "blurry" with the naked eye.

Take it off and focus with the rangefinder, which is binary - the two RF images are aligned (focused) or they are not aligned (unfocused). Much easier for the eye and brain to detect accurately. Especially with the shorter focal lengths of the M system (50mm or wider).

I find the focus peaking helpful but you’re probably right that I need to use the rf as well.

[adan]

3 hours ago, CP93 said:

I find the focus peaking helpful but you’re probably right that I need to use the rf as well.

One night a policeman comes across a drunk crawling around on the sidewalk under a street light.

"What are you doing, sir?" he asks. "I lost my wallet," is the reply. Whereupon the policeman gets down on his knees also, and they crawl around together, looking for the lost wallet.

After 15 minutes of searching with no success, the policeman finally asks, "Sir, your wallet just doesn't seem to be here. Are you certain this is where you lost it?"

The drunk says, "Oh, I didn't lose it here - I lost it in that dark alley over there!" Disgusted, the cop says, "Then why are we wasting time looking here!?"

The drunk replies, "Because the light is better!"

Moral: Focus peaking is easy to see - but not always the place to find correct focus. Too imprecise, especially with smaller apertures or shorter focal lengths

[charlesphoto99]

Not to mention focus peaking is incredibly distracting to relaxing and fully seeing the scene at hand, which in my mind is anathema to the reason for shooting an M in the first place.