Do I need glasses? EOS Diopter question...

Evening all (for those around my time zone).

I had a diopter question. I have noticed with the last two DSLRs I've owned (a temporary 30D and a 5D classic) that even with the diopter adjusted all the way counter-clockwise (not sure if this is a - or a + adjustment, pardon my ignorance) the view through the viewfinder is very slightly blurry. Pictures are sharp as a tack, and this is phenomenon is reproduced with all my lenses.

Do I need glasses? Am I right in assuming that the diopter adjusts so that the image will be perfectly sharp for people with 20/20 vision?

A trip to the optometrist is probably on the books anyway (it has been 15 years), but this made me ponder on whether a DSLR's viewfinder is a good (if informal) way to get an idea. Any thoughts?

The diopter adjusts the viewfinder so that you can see clearly...that is all. Just like the "1 or 2" drill at the eye doctor. It has no effect at all on the optical path for photos.

If you can't adjust either direction on the diopter control and get a clear vision through the VF, then yes, you might need glasses. Only your optometrist would know for sure.

To best set the diopter, point the camera to a blank page on your monitor, defocus the lens and set the diopter as needed to see the autofocus squares as sharp as possible. You may want to tune the setting in a few quick passes, relaxing the eye between them, so that the eye doesn't get then time to adapt to an imperfect setting.

Snydremark - that's what I suspected. I took a short break from photography in 2013, but during that time I took a job as a graphic designer. Add that to my freelance design work and it's not uncommon for me to spend 10-14 hours a day straight, seven days a week in front of a computer screen. That's a rather elevated amount, and could have had an effect on my vision (according to various web sources).

I might put that appointment on top of my to-do list.


Agedbriar - the focal squares look very nearly sharp, but there's a tiny but noticeable amount of blur to them at all adjustment levels.

You can also add a Diopter Correction to the viewfinder. They were originally designed for cameras that don't have a diopter correction. I use a +0.5 for my old EOS 630 because I need reading glasses. (my distant vision is Okay)

On my SL1 and 5D3 I have the correction wheel slightly clockwise to the + side and don't need to add a extra correction.

If you have you wheel all the way counter clockwise to the - side, I think you might need a additional -2 correction. (there is no -1 correction)

http://www.bhphotovide​o.com …on+diopter+e&mn​p=0&mxp=20

Time for reading glasses. If I forget mine my wife has to find something on the menu if we go out. I got progressives and now I can actually see details on my LCD. Made the lasted wedding much easier.

One eye is weaker so by the end of the day as they were adjusting to compensate I could not tell that I had a high def TV.

I'm the same.. I have trouble reading the LCD screen located on top of my 7D up close without my reading glasses.. I have to hold it an arms length away.

But, I have no trouble at all adjusting the diopter for a clear image. Actually, I only have to move it a couple of clicks to get the focus screen in focus.

Before it was readers on, readers off, readers on, readers off and repeat. My new cheaters are a peach.

For someone with 20/20 distant vision, a viewfinder presents an image to the eye as if one were reading a page from about 30" or 36" (depending upon manufacturer). If you cannot focus with diopter setting, your eye's lens for reading vision is not accommodating sufficiently...and your reading a novel or the newspaper should be similarly blurry!

I never have my glasses unless I'm at the office so when I go out to dinner my wife read the menu or orders for me... I need another 10" of arm extension to see the menu...

I'm near-sighted with astigmatism in one eye. Have to always wear glasses. But I hate them when out shooting, so I take them off and hang in pocket. Bought a Hoodman eyepiece and love it! It's the big one to accommodate eyewear, but I still prefer not wearing them.

I had LASIK done several years ago and need readers for up close work. I'm fine looking through the viewfinder on my 70D but can't see the lcd screens without the reading glasses. No problems adjusting the diopter for the viewfinder, all the viewfinder info is clear.

Wilt wrote in post #17289445
For someone with 20/20 distant vision, a viewfinder presents an image to the eye as if one were reading a page from about 30" or 36" (depending upon manufacturer). If you cannot focus with diopter setting, your eye's lens for reading vision is not accommodating sufficiently...and your reading a novel or the newspaper should be similarly blurry!

i like this advice. When my eyes are tired i can't see to read OR through the viewfinder.


I wonder if the diopter could be off a bit?


ClaranC, I am in a similar position. I do a lot of graphic design work too and if i am at the computer all day my eyesight is shot, actually it only takes about 6 hours before i start to notice the difference. I do a lot of product photography in the studio and manual focusing with tired eyes is impossible, even with live view.

About a year ago i bought a pair of +1 old man glasses from a drugstore. They are cheap and the plastic lenses are very hard to keep clean, but they work. I can use them for a short time and let my eyes rest a bit.

Adjust your diopter with totally fresh eyes and see if you can get it sharp.

Quick update - I just got my 5D back from Canon who replaced the entire mirror mechanism and focus screen under their recall/replacement program for the 5DC. The problem has been solved! Whether the mirror was misaligned or there was a an issue with the focus screen, I'm not sure but everything is now in sharp focus through the viewfinder somewhere between the center notch and the far left of the diopter.

I will probably still get my eyes tested since it has been so long, but I'm glad that the issue seems to have been fixed (without the need for glasses)!