Originally posted by fan22 Thanks for all the replies.
I had no idea those parts were so sensitive - I wish there was something mentioned in the user manual about cleaning do's and don'ts since this was my first dslr.
The image from the viewfinder is a bit hazy in some spots especially lights - should I just live with it instead of potentially making it worse if I assume the smudges are oil and try and get it off with a lenspen or something? Would a lenspen damage the mirror or outer viewfinder screen? I didn't press hard on the mirror because I was using the cloth to lightly brush off the dust so I'm guessing it's oil residue.
I'm getting a kx and certainly learned my lesson here. Has anyone experienced fungus on the viewfinder screen before? If not I guess it's scratches afterall.
A lenspen only works with pressure applied. Don't use it on the mirror at all. AND don't use it on the focusing (or viewfinder) screen at all. The "micro lines", pentaxpup refers to, are the grooves of the Fresnel lens (which is the cause, why a focusing screen can be illuminated evenly) and the lenspen will ruin those (there are tiny "balls" of cleaning agent in the lenspen, which will get stuck in these grooves).
The lenspen is only useable on lenses, that's why its sold under that name.
Question: How could you have oil residue on a microfibre cloth you use inside a camera? That should be impossible, because you would at all times only use completely new and unused material for cleaning the optical parts inside a camera - don't you?
O.k. now I give you a hint for cleaning the mirror, if it is really necessary: Use only PecPads or other completely lint free use-once pads (no cosmetic pads etc.) and apply two or three drops of pure(!) isopropylalcohol (pharmacie, highest quality they have or can order for you) onto the PecPad and then you can wipe it carefully (= very, very gently pressure only) over the mirror. Wipe only in one direction, down the mirror and avoid to rub or wipe in circles etc. The mirror is, as I wrote earlier silvered on its surface (different to household mirrors, which are mirrored on their backside, and that is the reason, why you can clean them easily) and very easily scratched.
End all you cleaning efforts with giving the mirror chamber a throrough clean with a Rocket Blower (no canned air, the pressure may be too high and damage the fragile mechanisms inside or you can end up with having even more oil residue on everything...). You would do that with the camera mount pointing down, in order to allow all dust, lost brush hairs etc, to fall out of the mirror chamber.
If I remeber rightly, the guide for cleaning a camera is right at the beginning of the manual and it does not mention cleaning mirror or viefinder or focusing screen for a reason.
Ben