[ChipB]

If the "stain" is on the focusing screen, then, according to the Katz Eye website Pentax K100D K110D K200D K x Focusing Screen - KatzEye Optics the screen can be replaced (even though it's not advertised as such). I've replaced one on the K200D - another one that's supposedly not replaceable - and, while it's not real easy, it's not too tough a job.

In order to determine whether it's the mirror or the screen, remove the lens and place a piece of white paper over the mirror - look through the viewfinder and see if you still see the "stain". If so, it's on the screen, if not, it's on the mirror.

Good luck.

[AbsoluteZedo]

Using that test i have concluded that the "stain" is on the mirror, Any suggestions on how I should go about removing the stain, i've tried a few things, but no dice.
Unless the mirror is somehow damaged.

[bobD]

Well I would hazard that the propellant from the air can has reacted with the aluminium coating to produce some localised "tarnishing".

Can you list the can contents so we can confirm ?

[AbsoluteZedo]

The content of the can, ie the compressed air bitterant = difluoroethane

I stupidly used a Multi-purpose cleaner during my panic stage and the contents are
listed on this website:
All Purpose Cleaner | Fabuloso Household Care

[Wheatfield]

Just remember that it is a very thin deposited layer of Fine (99.99% pure) silver.
Yes, silver is a metal but pure silver is a soft metal somewhere around 2.5-3 on the mohs hardness scale .

Pure gold, silver, and platinum are all relatively soft, with Mohs ratings between 2.5-4.
I am a jeweller and can attest to the softness of pure silver.

For reference fingernails are 2.5 on that same scale.

So what you are saying is that he shouldn't scrape the mirror with his fingernail hard enough to damage his fingernail?
Sage advice, I suppose, though I would hope unnecessary.

[AbsoluteZedo]

On the Moh's scale..pretty sure air doesn't have a hardness. Any damage that incurred is most likely from the cleaner and/or difluorethane, Assuming there is any damage at all. Thats what I am having trouble determining. My methods of cleaning have used things with less than a 2.5 hardness rating, xD.

[AbsoluteZedo]

Is the mirror even replaceable by itself or do you have to replace the whole assembly. It doesn't look like an easy task in and of it self

[ChipB]

Is the mirror even replaceable by itself or do you have to replace the whole assembly. It doesn't look like an easy task in and of it self

I've never heard of anyone replacing the mirror - I think it would be a pretty big deal.

[AbsoluteZedo]

Yeah It seems like it would be, just looking at the construction of it. It really looks like its permanently damaged...I hope its not. Even if it is i don't think its ground to buy a new camera just yet.

i'll have to get a professional to look at it. The sensor is pretty dusty too but that was probably from me looking at the mirror so much, i can probably easily clean that with an squishy airblowers and/or swabs, Or i might just get that professionally cleaned too. I really hope the

[Ex Finn.]

Not doing a mirror replacement in your garage.
It is locate in the "front housing block".

Screen captures courtesy of Pentax hack site.

[AbsoluteZedo]

Yeah...that looks pretty dangerous to do by yourself. I'm not much that would cost for a professional to do but it looks pretty expensive.

[Ex Finn.]

Might be a time to retire that body and go for a newer model.
I still "have" my K100D (my daughter took it from me), a good camera producing nice images.

[AbsoluteZedo]

It definitely is a good camera, its unfortunate i have to drop cash for a new body. I wonder if anyone would be willing to buy a functional camera with a slightly ugly looking viewfinder, and how much the value of the thing would be in general.