Originally posted by reeftool I had a real mess on my screen and also the mirror. I had changed lenses during a hike in the mountains last summer and the black flies were still swarming and several got into my camera. It took several tries with my blower and some gentle brushing with the fine brush that came with my blower to get it somewhat cleaned out. The darn things were walking around on the sensor and messed up some shots also. There are some spots still on the viewfinder but I did get the sensor clean. My Spotmatic has a petrified bug of some sort in the viewfinder for decades. Looks like a tick.
This happened to me earlier this year. I was at a zoo and there were a lot of tiny thrips (thunderbugs) in the air - getting all over everyone's skin and clothes.
I was using my FA50 on my K10D and one of the critters must have crept in through the gap under the focus ring, I presume this would be the only gap it could have gotten through. Soon after I noticed an enlarged and very detailed thrips crawling across my focusing screen! Not a pleasant sight.
I decided not to take any more pictures until I got home, just in case the mirror squashed it into the screen. I would try to blow it out in a bug-free indoor environment. This was very annoying as I missed taking some good pictures of the very entertaining prairie marmots.
I got home, dusted myself off, removed the lens and gave the mirror box a thorough blowing out. I did this over a sheet of white paper so I would notice if the bug had come out, but no bug! At least it had left the viewfinder.
It may still be in there to this day, but if so it hasn't caused any problems. Maybe it got stuck on the tacky floor of the mirror box...
A pity I've got no weather-sealed lenses. If so, then I wouldn't mind getting a camera out with thrips around. I suppose I could tape a plastic bag around it though!