[Thomas]

When I received my 645D the view in the finder was perfectly clear and rectangular. Now in the lower right corner of the view and irregular shape has appeared. It gives the look of excess glue or caulk oozing into the view of the finder. It's slight and has no effect on the images. Anyone else seen this goop appear?

[MarkJerling]

Are you sure it's not loose material? I.e. a bit of dust on the focus screen?

[Thomas]

No, it's not loose nor is it dirt. It looks like excess material of a rubbery nature that has been squeezed into the visible area. It appears right at the lower right edge.

[JinDesu]

Is there any possible way you can get a picture of this?

[Thomas]

The best I could do. Light reflecting off an outside table through the viewfinder and I shot the image on the reflex mirror. When looking through the finder the irregular shape is quite opaque with distinct boundaries, not as it appears here (may be a focus issue with my shot). As you can it doesn't cover much of the finder, but what is it?

[-Linus-]

and the mirror itself looks OK?

-Linus-

[Thomas]

The mirror is fine, it's something in the finder.

[Silent Street]

Fungal growth/mold.

[672]

Have you pulled the focus screen? Ever? Looks like it could use a cleaning and perhaps that will reveal the nature of the obstruction.

[Thomas]

Have you pulled the focus screen? Ever? Looks like it could use a cleaning and perhaps that will reveal the nature of the obstruction.

No I never have. I have none of the focus problems that others have reported and so I'm very reluctant to disturb the optical path. I may try that at some point, but since it doesn't affect photos, I'm in no hurry*. I am curious if anyone else has seen this.

I'm quite sure it's not fungus, having seen many examples. This material has a very distinct boundary, not apparent in the photos.

* Update: Curiosity got the best of me; I pulled the screen, nothing there.

[672]

okay, so you pulled the screen and still saw the obstruction. then its either foam seals in the screen area which have deformed , or as you have said, heavy adhesives in the prism area which have migrated for some reason.

[672]

Um, Thomas, what happened with your viewing system ? Is it clear now?

[Thomas]

Thanks for asking, but it's the same. It doesn't look like something that would go away on its own. It has no effect on seeing through the finder, other than seeing a weird, wavy line at the bottom, so it's not worth the time and expense of sending it for service. In the old days, before the dearth of service centers, I would have walked in to Pentax Canada for immediate evaluation.
I'm curious if anyone else has seen this. I vaguely remember a post mentioning something like this.

[mazwick]

Thanks for asking, but it's the same. It doesn't look like something that would go away on its own. It has no effect on seeing through the finder, other than seeing a weird, wavy line at the bottom, so it's not worth the time and expense of sending it for service. In the old days, before the dearth of service centers, I would have walked in to Pentax Canada for immediate evaluation.
I'm curious if anyone else has seen this. I vaguely remember a post mentioning something like this.

Hi there,
Ihad exactly the same effect.
As the body was still under warrenty I sent it to the service. they said:

Extreme heat caused a kind of "glue" of the prism to "melt".

I was in africa and there was some direct sunlight going into the viewfinder, but it was no real extreme heat. The service repaired it, but with much hesitation. they said it was a mishandling of the body. Finally they surrendered and they did it free of cost.

There is definitly no effect on the IQ. I insisted as I wanted to sell the body as good as possible.

Martin

[Thomas]

Thanks Martin, that makes perfect sense. I wonder what the Pentax definition of extreme heat is? My camera has never been above 110F, although it is possible it was left on a tripod for a short period when the sun may have coincidently been shining at the eyepiece.