dirty, blotchy area/spot in the bottom corner of viewfinder, but isn't the sensor?

using my 5dmkii in london right now. i was trying to blow off a piece of lint on the mirror, somehow got this blotchy, dark area that i now see in my viewfinder. but it doesn't show up in the pictures, so it's not the sensor for sure. i've tried cleaning it but no luck (the mirror and the screen).

how does one normally clean/remove these spots? really annoying me every time i look through my camera.

would i have to take apart my camera to get into the viewfinder? could be my focus screen (can i even remove that without the little tool?)?

my 5D II has a few black specs in the viewfinder. it is annoying, but doesn't affect picture quality or show up in photos. I tihnk there is a way, but it does involve taking a few pieces off your camera to get to it, which in that time, you may introduce other contaminants.

give it a while, and you'll forget they are there.

Just remember that if you can see it in the viewfinder, it can't be on the sensor and you'll be ok. It could be from the black foam the mirror lifts up into,f I get it occasionally and just live with it or blast it with the blower until its gone. I wouldn't worry about it unless it really bothers you.

It sounds as if it's either on the mirror or the focus screen... Merrely a nuisance, won't effect images.

The focus screen is easy to remove... Go buy a pair of plastic tweezers and use those to grab the little tab, after unclipping the focus screen. Be careful not to touch either the front or the back of the screen, and most especially not the mirror. That's very delicate and easily damaged.

If it's on the mirror, I strongly suggest you take it to a local camera repair shop to have it cleaned. Don't try to do it yourself. You risk damaging it and it will be very expensive to repair.

If the focus screen is damaged, it's not a huge thing... Costs less than $50 for a replacement and you can put it in yourself. The new one will come with the little tweezers, by the way.

But a repair shop might be able to clean the focus screen, too. It's optical plastic and easily damaged, too... so be careful.

There are also foam light seals/bumpers around the focus screen. Be careful to not damage those, either. But if they are getting old, they can crumble and be the cause of stuff you see on the mirror and focus screen. Again, a local camera repair shop should be able to replace the light seal, if needed.

None of this would be expensive... Unless you try to do it yourself, screw something up and end up having to have major repairs done. No, I don't recommend you take the camera apart and try to get into the viewfinder and pentaprism area. You might never get the camera back together! At the least, you have to be very careful, there are often adjustment shims used in there to be sure everything is perfectly aligned. There are a lot of parts and some electronics involved in disassembly, too. The pentaprism and viewfinder are usually pretty well sealed against stuff getting inside anyway, on most cameras. It's much more likely the stuff you see is on one side of the focus screen or the other, or on the mirror.

amfoto1 wrote in post #12752829
It sounds as if it's either on the mirror or the focus screen... Merrely a nuisance, won't effect images.

The focus screen is easy to remove... Go buy a pair of plastic tweezers and use those to grab the little tab, after unclipping the focus screen. Be careful not to touch either the front or the back of the screen, and most especially not the mirror. That's very delicate and easily damaged.

If it's on the mirror, I strongly suggest you take it to a local camera repair shop to have it cleaned. Don't try to do it yourself. You risk damaging it and it will be very expensive to repair.

If the focus screen is damaged, it's not a huge thing... Costs less than $50 for a replacement and you can put it in yourself. The new one will come with the little tweezers, by the way.

But a repair shop might be able to clean the focus screen, too. It's optical plastic and easily damaged, too... so be careful.

There are also foam light seals/bumpers around the focus screen. Be careful to not damage those, either. But if they are getting old, they can crumble and be the cause of stuff you see on the mirror and focus screen. Again, a local camera repair shop should be able to replace the light seal, if needed.

None of this would be expensive... Unless you try to do it yourself, screw something up and end up having to have major repairs done. No, I don't recommend you take the camera apart and try to get into the viewfinder and pentaprism area. You might never get the camera back together! At the least, you have to be very careful, there are often adjustment shims used in there to be sure everything is perfectly aligned. There are a lot of parts and some electronics involved in disassembly, too. The pentaprism and viewfinder are usually pretty well sealed against stuff getting inside anyway, on most cameras. It's much more likely the stuff you see is on one side of the focus screen or the other, or on the mirror.

thank you all for the reassurance!

i did try to lightly clean the mirror and screen with a promaster lens cleaner (sprayed it on the special towel and gently tried to clean the areas). when i get home i'm going to take it in and have it cleaned somewhere locally.

if i screwed up the mirror, (don't think i did but worse case scenario) how would i know? would i see immediate effects on picture quality? would i hear it or notice it in shooting? thanks again