Pentax K100D viewfinder cleaning ?

luisalegria · Expire: 2018-01-18

Gents,

My over-used Pentax K100D is still functioning well after 60,000+ clicks, but it has developed a problem. The viewfinder coating is bad on the outside, and scratched (I must have sandpaper eyeballs ?), and it looks like there is condensation and dirt on the inside of the viewfinder as well, or on the part of the prism near it, or perhaps the diopter lens.

I have checked the focusing screen and the dirt isn't there.

Still functional, but the viewfinder on this was small and dark to begin with, and its worse now.

I can't see any obvious way to disassemble just the viewfinder. I would also consider replacing the whole viewfinder asembly if necessary.

Any idea about where to get Pentax service manuals or parts for K100D ?

scsambrook · Expire: 2011-11-18

I also have a K100d but haven't had any vf problems ... yet. I suspect that the eyepiece lens might actually be plastic rather than glass, which might mean it's more likely to scratch even with careful cleaning. In any case, I'm convinced the viewfinder eyepiece isn't sealed at all, so airborn particles could make their way into the viewfinder system.

Can you atually SEE the dust/dirt you mention? If you can, then I bet it's sitting either on top of the focusing screen or under the pentamirror, although I'm not sure if pentamirrors actually have a "bottom" surface. My K10d has some foreign bodies on its lower prism face and they show as blurred "shadows" through the viewfinder.

luisalegria · Expire: 2018-01-18

Hi Scsambrook,

Thanks for your reply.

I have scratches and coating loss on the eyepiece lens, which I would like to replace, but this is in addition to the other visible dirt and haze. I have removed the focusing screen and both it and the bottom of the prism/mirror seem clean. The problem seems to be at the eyepiece end, or at any rate somewhere I can't reach without more complete disassembly.

scsambrook · Expire: 2011-11-18

It sounds as though Pentax don't want to let us deal with problems easily! My K100D eyepiece is actually a little loose, it 'wobbles' when you change the diopter setting, which hardly promises for a good seal. I tend to use it on the house and garden for close-ups, so it leads a fairly sheltered life, unlike yours which obviously gets plenty to do! Maybe you'll need to send it to a Pentax service station?

I bought my K10D secondhand, and its done about 10,000 clicks, and the viewfinder is quite messy to look through. But it's all screen dirt, so at the worst I can fix it with a new screen.