Warning to EM-1 users :sunshine into EVF can create indeletable blotches, as confirmed by Olympus.

Started Jun 4, 2014 | Discussions thread
Anders W Forum Pro • Posts: 21,468
Re: Question

Its RKM wrote:

Anders W wrote:

Its RKM wrote:

Anders W wrote:

Its RKM wrote:

Anders W wrote:

Its RKM wrote:

Anders W wrote:

luisflorit wrote:

Sorry for being late: is there any of the proportion of users in the forum experiencing this problem, and which diopter adjustment the affected users use?

As to the diopter adjustment, the problem should be worst if it is set to zero, i.e., such that a person with perfect vision of perfect glasses can view the EVF with maximum convenience (as though it were at infinity).

I think you'll find that most non-adjustable SLRs had their viewfinders set to position the screen at around 1m viewing distance, not infinity, and that's what the "0" on most adjustable viewfinders corresponds to.

I have never seen any test of what they are actually set to (if not adjustable) or set to at 0 (if adjustable). Have you? If so, I'd be grateful for a reference/link.

I know I have seen this in various service manuals, but I no longer have access to any of those.

Here is one reference which suggests Nikon default is -1 dioptre: see note below the table of corrective lenses. https://support.nikonusa.com/app/answers/detail/a_id/639/~/viewfinder-diopter-adjustment

However what I did do, and you might be able do the same to check for yourself, is dug out my old OM-1 & OM-2 cameras, which don't have any eyepiece adjustment. I then used my OM-3Ti with 50mm lens to shoot into the eyepiece of the two older cameras. Best focus of the screen information was when the lens was focussed at 1.5m for the eyepiece of both cameras. At infinity the focus through the eyepiece was clearly off. This confirms what I believed, but you can probably do a similar check to confirm it for yourself.

OK. That's a good enough test. I don't have any old film SLRs left to play with and haven't yet tried to check what the midpoint or zero-point of my various MFT bodies actually corresponds to.

I just managed to grab my wife's EM-1 out of her hands for a couple of minutes and did a similar test on that at the dioptre setting she is using. Again, best focus was at 1.5m. Since she had ELRT some time ago, her eyesight is perfect, so I'm pretty certain that would be the nominal setting.

Of course, having just done the test, its all a bit moot anyway since the EM-1 doesn't have a marked "0" or other indicator, so you have no idea what it is actually set at.

And why would they be set to anything but infinity? That's where the eye is most relaxed, right?

It may be where the eye is most relaxed, but it is also at one extreme of the accommodation range. It makes more sense to put the image in the middle of that range.

Why would that make more sense? The point where the eye is most relaxed is certaily the one that makes most sense to me. That's also where I personally set it when it is adjustable.

How do you know that's what you are doing? Since infinity is as far as your relaxed eye can go, you'd have to set the adjustment as far as it can go towards infinity while you can still keep the image in focus.

That's exactly what I do. I like to keep my eyes maximally relaxed.

So sometimes you pick up the camera and the eyepiece isn't in focus.

No. That never happens. Accomodation is instant.

That's what would happen if you adjust for one extreme of the range you can accommodate, the eyepiece isn't athermal. There seems no point in adjusting the viewfinder for that condition.

I have never noticed any temperature variations in this regard. If they exist, they are too small to matter.

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