Diopter adjustment: is it necessary?

[biglouis]

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I have a question which is taxing my brain since acquiring a M4-2.

 

I'm about to go out and use the camera for the first time. Now, I am long sighted which means I do not see image in the viewfinder in sharp focus. However, having played with the camera I do see clearly enough the merging of the two images into a single image when focussing. I do this by looking at the edges and making sure one is over the other (which I guess is the way everyone does it).

 

Here is the question - if I use this technique, does it really matter if I can 'see' the image as focussed? Is the image correctly focussed as long as I have ensured that the two images are correctly merged?

 

I ask because I find it difficult to peer through the viewfinder with my glasses on.

 

TIA for any advice

 

LouisB

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[brunom]

Louis

 

In essence what you have described is ok. As long sighted I'm assuming you see ok all around you but have problems close up, which is what I have. I use a +1 and everthing through the viewfinder is as sharp as my distance viewing. Why not use a dioptre lens?

 

Bruno

[lars_bergquist]

I'm longsighted too, but use multifocals, i.e. with far focus at the top of the lenses, and close focus at the bottom. So head and camera position is really instinctive, or became so after a little bit of practice. Both subject, frames and rangefinder are seen with crystal clarity. (BTW, the optical or virtual distance to the frames is 2 meters.)

 

The only drawback is that my camera is a M4-P, and the 28 mm frame cannot be seen in its entirety at the same time, because of the higher eyepoint. So I experimented with an appropriate screw-in correcting lens, but found myself half-blind except when looking though the finder. Adjusting f-stops or speeds or reading a Leicameter thus necessitated the infamous specs off-specs on drill. I found that I could live with a bit of 'guesstimating' when using the 28, which is not one of my mainstay lenses on FF.

 

However, the old, pre-M6 eyepiece rim is sheer murder with synthetic glass lenses. So I

obtained a complete new rubber-rimmed current eyepiece for my camera. Any competent camera mechanic can do the replacement. Please don't try to do it yourself.

 

The old man from the Age of the Brilliant Finder

[biglouis]

Louis

 

Why not use a dioptre lens?

 

Bruno

 

Bruno, I suspect a +1 would be adequate for my prescription. I'll try to get one but in the meantime I was just checking that my assumptions are correct. Thanks for your advice

 

LouisB

[moikle]

Here's a useful link to one of LUF's members site.

 

Leica FAQ - M eyepeice correction lenses - how to estimate?

 

Mike

[rick_dykstra]

Note that the M cameras have a built in -0.5 dioptre correction. This helps us shortsighted folks a little but might be something of a hindrance to the long-sighted. If your prescription is +1 for specs, you might need +1.5 for comfortable focussing. Any optometrists on board?

 

Would wearing your reading glasses while shooting be an option? I wear my 'driving' glasses usually for M work, or screw in a -2 dioptre (which works for my -1.75 dioptre with a little astigmatism script).

 

Best bet would be to get to a good dealership and try a few dioptre lenses out.

[robsteve]

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I am still a bit confused about this diopter thing.

 

Are people fitting diopters to use the viewfinder without their glasses or fitting diopters to correct focusing problems they have even with glasses on?

[brunom]

Robert

 

It's usually to enable clear viewing through the finder without glasses on.

 

Bruno