Astigmatism and rangefinders

[Bob Ross]

Advertisement (gone after registration)

There is an interesting article by Ctien about how astigmatisn can change the way each of us use a rangefinder, on Mike Johnston's site. Scroll down to the article titled Rangefinder Follies.

THEONLINEPHOTOGRAPHER.COM

Bob

[Advertisement]

The Leica Q3 is available for pre-order at B&H Photo Video and Adorama

[sm23221]

He brings up an excellent point. I wonder how many lenses and camera bodies "went back to Solms" because of uncorrected astigmatism, myopia and hyperopia.

[john_nyc]

Wouldn't astigmatism only cause a problem if you're keeping both eyes open while shooting?

 

I have astigmatism, and if I'm not wearing glasses or contacts and I close one eye, my double vision magically goes away (as does my depth perception).

 

I know a lot of people do shoot with both eyes open, but I could imagine that unless the VF has a 1.0x mag, having one eye see at 1.0x and the other at say, 0.72x is sort of like inducing an astigmatic state. That's why I could never get used to it when I've tried doing it.

 

I'm no expert on vision, I'm just speaking from experience with my own defective peepers.

 

John

[Bob Ross]

Astigmatism.....probably more than we want to know...

Astigmatism - Wikipedia, the free encyclopedia

I have a slight bit of it, but enough to correct and all my lenses focus fine without glasses, but with a diopter correction. Who knows?

Bob

[jaapv]

:D I've been flamed repeatedly for saying this. The number of people who will blame the tool before looking at themselves for a simple explanation is amazing.

[lxlim]

:D I've been flamed repeatedly for saying this. The number of people who will blame the tool before looking at themselves for a simple explanation is amazing.

 

Did not flame you. but it probably was under corrected astigmatism for me when I sent in my M8 to Solms. I did not understand rangefinders then. Pro or no Pro, I learnt a great deal from this forum.

[andybarton]

Advertisement (gone after registration)

This is an extremely interesting link - we should put this into the wiki, or somewhere else where people with focussing problems could be directed.

[Phillip_Meyer]

I would imagine that problems with focusing the rangefinder due to un-corrected or under-corrected astigmatism would depend on the axis of the astigmatism.

 

Because the rangefinder on the Leica focuses the images across the horizontal plane, I'd guess that the closer the axis is to 90 or 180 the more it could impact. I would also suspect that it is probably only going to have an affect on lower cyl powers because people who have large cyls would probably just get a blurred image whatever they look at. However, I'm really not too sure I'd have to work it out.

 

I have an uncorrected -0.25 cyl, perhaps that's what's causing all my problems, however, my problems have been with some but not all lenses and have been verified by other people (shop owners) and on other bodies. Therefore I suspect this could be a problem in some cases but is unlikely to be the problem with the majority.

 

Phillip

[jaapv]

The solution, Philip, is to visit an optician and try focussing the camera with the correct trial glass between your eye and the VF. The way you can rule out your eyes as the cause. It seems unlogical, but rangefinders require near-perfect eyesight correction.(or enough experience to compensate)

[andybarton]

It should not be forgotten that a dioptre correction lens will not correct for an astigmatism. Consequently, anyone with an astigmatism would need to have correction for that "off-camera"

 

I am a left-eye shooter, with a mild astigmatism and always wear my glasses when shooting. I tried a dioptre corection lens, but had no joy with it at all.

[cme4brain]

He brings up an excellent point. I wonder how many lenses and camera bodies "went back to Solms" because of uncorrected astigmatism, myopia and hyperopia.

 

 

Those lenses sent to Solms came back and the problem they were sent for (poor focusing) was corrected, implying an equipment problem. Had the poor focusing been attributable to poor eyesight, I would image the focus problem would have persisted.

 

I have noted however that with my 50 year old post-LASIK eyesight I have some difficulty focusing my M8 and M6. I therefore am not spending $$$ on fast lenses (f/2.0 or faster) with shallow DOF as my eyesight alone would create focusing errors. I need a larger DOF to correct for this.

[andybarton]

You have just convinced me not to have my eyes lasered. Thanks!

[jaapv]

It should not be forgotten that a dioptre correction lens will not correct for an astigmatism. Consequently, anyone with an astigmatism would need to have correction for that "off-camera"

 

I am a left-eye shooter, with a mild astigmatism and always wear my glasses when shooting. I tried a dioptre corection lens, but had no joy with it at all.

 

Leica does supply an "empty"dioptre correction glass holder for an optician to put a specially corrected dioptre lens in. I think Leica bei Meister has them in stock.

[andybarton]

When I spoke with my normal optician, they told me that they couldn't make a properly corrected lens small enough to fit the correction ring.

 

It would also be necessary to have the lens set such that the eyesight was perfect when focussing at 3 feet, from what I understand.

[jaapv]

That is quite possible. An optician friend told me that glass makers like Zeiss have severely limited the choice of lenses in 10 mm, nor do modern shaping machines allow the grinding down to that size.

[Ronazle]

Perhaps this will add to the discussion without distracting it too much: about 1965 I decided to try SLRs and put aside my Leicas and went on a SLR binge. After missing about a million good photos I returned to Leica rangefinders. Apparently, my fairly strong astigmatism was coupled with a very strong optic muscle (?) causing my eye to follow focus in a rather pronounced manner. This caused prolonged focusing without clicking the shutter and ,hence, missing the photo. This was only present through prisms not on ground glass.

On the other hand, my astigmatism (corrected w/conventional glasses) has no problems at all with rangefinders. Using test targets (and a 1.25 magnifier) my 90mm Summicron focuses fine although it did have a backfocus problem when I acquired it (used).

[sm23221]

When I spoke with my normal optician, they told me that they couldn't make a properly corrected lens small enough to fit the correction ring.

 

The size is not the real issue. If an inidividual has an appreciable amount of astigmatism they would necessarily have to rotate the eyepiece 90 degrees to obtain the same correction when shooting a vertical frame. That could become a real pain and is very inconvenient.

[sm23221]

Those lenses sent to Solms came back and the problem they were sent for (poor focusing) was corrected, implying an equipment problem. Had the poor focusing been attributable to poor eyesight, I would image the focus problem would have persisted.

 

I have noted however that with my 50 year old post-LASIK eyesight I have some difficulty focusing my M8 and M6. I therefore am not spending $$$ on fast lenses (f/2.0 or faster) with shallow DOF as my eyesight alone would create focusing errors. I need a larger DOF to correct for this.

 

I would imagine some truly had mechanical problems but I've read many posts that stated the lenses were returned "without being fixed". The point being, every photographer should ensure they have the best corrected distance vision first before sending in their lens.

 

Being presbyopic should not affect your ability to focus a rangefinder. I would consider other factors such as lens or media opacities, or possibly higher-order corneal aberrations as a result of having refractive surgery.

[Advertisement]

Hallo,

Look here: Leica M

[Bob Ross]

I have a friend that had an eye fatigue problem with her DSLR and eventually traced it to astigmatism. Fortunately the AF helped with photo output, but as she continued to shoot her composition got sloppy. I haven't gotten an update on her situation. So, the smaller dimmer SLR finders of DSLRs, that might even carry their own astimatism to add to the user's are also something to know about. I do know that I am very viewfinder sensative and buying the top end models to get the best available VF has beem my solution. These MVC-P&Ss (micro view camera-point & shoot) with their LCDs are still something I have to get used to or skip altogether.

Bob

[luigi bertolotti]

This is going to be a really interesting thread... I'm not so expert of eye defects, but I do wear glasses and have astigmatism at the right eye only (always use left on Leica VF... accustomed for years...) : anyway, my contribution for what is worth... these two pics were taken (100% crop) in the standard way.. tripod, 45°, distance 1,5 m, Summarit 75 wide open, BUT I used my RIGHT eye, and in BOTH I made the RF align "the best I can" (continue not to like much the short helicoid of Summarit...).

The first is WITH my glasses ON, the second with my glasses OFF

 

spectacles ON

Welcome, dear visitor! As registered member you'd see an image here…

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

 

spectacles OFF

 

Repeat, in BOTH I aligned the VF at MY best, of course at the center line... rather impressive... one could even think that my lens has a randomly "floating" element...