I've used a Giotto's blower to blow off both sides of the focusing screen - any other ideas as to what could be causing dust in the viewfinder? Doesn't show up in photos, just bugs the hell out of me when I compose a shot and see dust...
I assumed blowing the focusing screen would have done it, I suppose I could replace the screen, just wondering if there is something else I'm not thinking about (don't want to replace screen, just to find out it didn't help).
If you've removed to focus screen to blow off both sides then perhaps a particle or two of dust have settled on the bottom of the pentaprism or depending on how recent your camera the lcd screen that is installed between the pentaprism and the focus screen. Other than that perhaps on the mirror? I would guess the more in-focus the dust appears the closer to the focus screen.
The focusing screen has a high dust resistance, to the point where the dust simply falls off the screen just by tipping and shaking it a little.
The superimposed indicator plate though is a dust magnet, and it is where the dust clearly visible in the viewfinder is most likely to be. Cleaning it is a bit harder though, as it involves a bit of work removing a couple screws and taking care not to let the small metal parts fall onto the mirror or sensor.
