Hi. I need glasses, technically. I prolly won't get any til I get my driver's license. However, I believe it's affecting my photography. I shoot predominantly with my left eye (which I discovered years ago to be my "strong" eye), even though I have an astigmatism. Both my eyes are slightly myopic (near sighted), not enough to make living day to day a hassle (in fact, I rarely notice unless I try to focus on signs far away. They don't look blurry, but I can read them with a friends glasses clearly, and I also have to sit in the front row of class to read blackboards). However, I would like to get one of them thingiemabobs to mount on the viewfinder of my nikon slr. Any idea what correction Ishould get depnding on an eye test, meaning, is there some wierd division to do in order to get the right eye piece, or if I'm -2, should I just get a -2 piece...? thanks, relutantly non-4-eyes, ry

It's called a diopter I believe....and I would imagine that going to a store and testing them out would be the best thing to do..... blind as a bat without my 3rd and 4th eyes

Yea, I'd go with Michelle's suggestion. Try them out in a store. Each manufacturer has a different formula for figuring out which diopter you need. However, someone correct me if I'm wrong, Diopters are meant to be used -with- your eyeglasses or contacts. Diopters aren't like glasses that compensate for things like myopia or astigmatism. They compensate for the difference between seeing normally (with your glasses/contacts) and seeing through the camera. I think that's right, since all the diopter formulas I've ever seen took your prescription and subtracted some number from it to get the diopter you'd need. -=>Donald

You actually try to see the things you photograph? Always a good idea to get a checkup once and awhile from an opthimologist. Maybe student medical services? [They like to practice on living people occasionally...] Likely they won't have a clue about cameras, but doesn't hurt to ask.

Attached Link: http://medfmt.8k.com/mf/diopter.html

Maybe helpful?...... Diopter lenses are used in photography for: closeup photography - the familiar +1/+2/+3/+4 diopter closeup lens kits reducing minimum focus distances (fractional diopter lenses +.25, +.5) changing the focal length of lenses (front of lens adapters, LF etc.) eyepiece corrections for failing, aging, or bad eyesight screw-in 35mm eyepiece diopters for pro cameras variable diopter adjustments on Chimney style viewfinders (Hasselblad) fixed diopters mounted in prism viewfinders on many medium format cameras eyepiece corrections for astigmatism or other vision defects (custom lenses)

Just got new glasses before christmas. I'm blind as a bat. With -7.2 left and -6.5 right. Take my glasses away and everythings a blur. Unfortunately that also means extremely thick lenses or very expensive high index synthetics (I chose the latter). -- Mark

Just so you know... If your problem is an astigmatism diopter may not do the trick. It depends on how severe the astigmatism is. If your probem is all astigmatism diapter alone won't solve the problem. its also a matter of axis. for people with an astigmatism the world is blurry both close and far. If you are just near or far sited diopter will work. Talk to your eye doctor and they can explain it better than I can write it. I have a severe astigmatism and I can see clearly without my glasses at any distance. Plus I was an optician for 12 years (the one who makes the glasses). Magick Michael

I used to have glasses for my farsightedness and astigmatism ('used to' because they got trampled on at a gig last year). Sometimes, even with the glasses ('cause they get in the way), I actually have difficulty seeing the cross hairs during manual focus (I don't have auto focus). Will the diopter help? My optometrist recommended contact lenses, but I find them too tedious for my lifestyle. (I only need it for reading, photography and puter use.) (*

Diopter will help the farsighted issue but the astigmatism will not be affected. If the astigmatism is less that -1.00 (the middle number or Cylendar) you should be OK without glasses.

hummm. i used diopter lenses for years before i realize they waz absolutelky useless for my astigmatism. I've a really bad vision from the right eye (-9.5) and a really good one from the left (more than 12,25), in some cases my left eye weakens and my vision falls; this means that many times my own eyes dof and distance evaluation distorts... to not mention when my left eye simply gives up and all blurs =) Not funny ... when i was younger (8-9 yo) my vision with the right eye was really better and for some times i've tried dioptic correction lenses but i was forced to use glasses anyway to shot. The Diopter lenses cannot correct an astigmatic issue as zhounder said. The trick is to choose tha most comfortable glasses (with really light mount) and an High Eyepoint camera. Most of the recent SLR cameras of middle-high and high level has an HP pentaprism. some old ones can be refitted if the body has an interchangeable pentaprism (a Nikon F3, for example, has an HP pentaprism as an option; Nikon F5 has an HP pentaprism for itself... and F100 too i think). I dunno what kind of camera you have... a great help can come from your camera's focal screen... for example i've always used as a reference my Nikkormat stygmometer to be sure of the focus when my eye was tired. A nice solution (if you have enough money) is buy a telemeter camera... focus is a lot easier coz you see 2 images and you have to make them surmount to have the right focus on the scene...