Dumb question about diopter..

[skydragoness]

I hate having glasses..

anyway, i noticed while playing around w/ my M42 manual focus lenses that sometimes what appears in focus in the viewfinder doesn't show up that way on the screen after the shot.

I'm supposed to adjust the diopter without wearing my glasses right? Duh..

[wirrah]

I either wear glasses and set the diopter to zero or don't wear them and set it all the way to the right in my case. That's -3 on my *istD. Either way I have to use my glasses to see in the distance clearly. If I set the diopter to zero I have to take my glasses off to see the LCD screen clearly.

That said I have found that best focus (even if blurry) is still correct focus even if I don't have glasses/diopter correctly set but that may be just me. Without glasses or the diopter set no part of the image is ever in focus.

cheers

Greg

[LeoTaylor]

To adjust the diopter I first get the sensor in focus, easily done with an autofocus lens and a simple scene. Then I adjust the diopter so the viewfinder is in focus. I remember its position in case I bump the slider. I >think< you could adjust the diopter with or without glasses as long as you continue to use it the way you calibrated it. Your manual focus lens will be fine once the sensor and viewfinder match.

After years of using manual lens I'm discovering the AF lens does better than my eyes. I still focus special stuff manually with the K110D, but for my regular photos with a K100D I use the kit 18-55 and its buddy 50-200.

[WMBP]

Originally Posted by skydragoness

I hate having glasses....

Yeah, me, too.

I'm supposed to adjust the diopter without wearing my glasses right? Duh.

Yes. And when you are adjusting the diopter, remember that you are NOT trying to get a photographic subject into best focus - you are trying to get the info at the bottom of the display into best focus. By "info at the bottom" I mean the info about shutter speed, etc. The diopter is correctly adjusted when that stuff is as sharp as it can be. So you can adjust the diopter in a dark room or while pointing the camera at a blank wall.

Will

[AndrewG NY]

I usually have the diopter all the way to (or one click shy of) the right. My nearsighted vision is good enough that I can then use the viewfinder with or without my glasses on.

The diopter adjustment technique that I've been using is:

a) Aim at a blank light-colored wall.
b) Don't worry about whether the lense is in focus or not. You might even find this easier if lens is out of focus.
c) Focus the diopter so that the focus screen AF frame markings are sharp

This would roughly correspond to the earlier suggestion to adjust the diopter so that the viewfinder LED info was sharp.

On a related topic I recently have been trying out the Pentax O-ME53 Magnifying Eyecup, and I'm still deciding on how much I like it. It does appear to enlarge and brighten the viewfinder a little. The downside is that it also introduces some viewfinder vignetting and you can't see the whole frame & viewfinder LEDs anymore without moving your eye around a bit. This effect is of course even worse while wearing glasses.

I tried this on a K10D. I suspect that it might work a little better on a K100D or K110D as the viewfinder magnification is a little lower to start with. I don't own any bodies with smaller viewfinders to try it on.

I am thinking this might be most useful when working more deliberately, such as with an ultra wide angle lens, perhaps with a tripod. The ultra wide angle image tends to be a little tricky to focus critically as your details are very small in the viewfinder.

[LeoTaylor]

To me the purpose of the Diopter adjustment is to make the subject in the viewfinder in focus the same focus position where the lens is focused on the sensor. I depend on visual focus with many manual lenses.

That said, I tried Will's method of focusing the text below the display and was amazed to get the same results. I know my setting (one click left of center on both cameras) and the text method zeroed in on the same result. I was even doing the adjustment without a lens on the K110D.

It is much easier than the method I mentioned in this thread though once you memorize the correct spot you need not adjust again.

I wonder if anyone will chime in with an example where the text method results in out of focus images.

Originally Posted by WMBP

Yeah, me, too.




Yes. And when you are adjusting the diopter, remember that you are NOT trying to get a photographic subject into best focus - you are trying to get the info at the bottom of the display into best focus.

Will

Hmm, good stuff Will. I hadn't thought of that. Will surely give that a try.

Ed