Diopter Question

[Donovan]

Hello,
I am new to the Bessa world. I recently purchased a R2A with a CV 50/2.5 Color Skopar and I have enjoyed it so far. I wear prescription eyeglasses (can't see far away) and I was wondering about diopters. If my pictures are in focus (as I saw them through the VF) does that mean I don't need a diopter? Or can a diopter make it easier for me to focus? The LED shutter speeds at the bottom of the VF (when using AE) are kinda wacky visually but I've heard other people think they are not too clear. Would a diopter make the shutter speed more readable? Basically, what is the benefit of a diopter if your glasses are producing 20/20 before one looks through the VF? Thanks for any responses.

 

[silverliner]

You need to go back to to your optician/opthalmologist for detailed examination. You may need a new pair of glasses with progressive lenses in case you are over 40 now. The focusing power of our eyes is poorer as we are getting older. If you can still recall, when we were very young kids we could bring the book really close to our face and still we were able to read those words. Do it after you turn 40 and see the difference. The numerical speeds in R2A viewfinder were set at a certain distance probably 2 feet away and that can be troublesome for those having presbyopia. I myself need a new pair of progressive lenses every two years otherwise I cannot focus most of my cameras.

 

[john_s]

If you wear your glasses when using your camera, you should be able to focus well.

If you prefer to not wear your glasses while using the camera, a diopter correction would probably help. If your eyeglass prescription is mostly spherical, a diopter will be useful. If you have a significant cylindrical component to your prescription, a diopter can not correct for that.

An example: I am short sighted and need glasses for driving. My right eye prescription is -1.5 spherical and a tiny amount of cylindrical that I can ignore. For most cameras a -1.5 is good. Note that for the Bessa cameras the diopters for the Nikon FM series fit and might be easier to source. According to the Nikon web site, the marked diopter on their correction eyepiece lenses is the value of the lens added to the constant value of the camera viewfinder which is -1. So the Nikon diopter marked "-2" is actually a -1 piece of glass.

When in doubt, a slightly lower value might be safer. Trial and error in low light is the best way to choose the right value.

As silverliner said, as you get older your eye's ability to adjust becomes less, making choice of correct value diopter more critical.

 

[ClaremontPhoto]

If my pictures are in focus (as I saw them through the VF)...

A rangefinder camera is focussed by aligning two images, not by looking at the scene as would be the case with a single lens reflex camera.

 

[john_s]

A rangefinder camera is focussed by aligning two images, not by looking at the scene as would be the case with a single lens reflex camera.

True, which is why RF is so much better than SLR in low light. But for those of us who don't see well, it's still better to have the correction as good as possible.

 

[silverliner]

A rangefinder camera is focussed by aligning two images, not by looking at the scene as would be the case with a single lens reflex camera.

Right! But without good or corrected eyesight how could one make a perfectly superimposed images?