Does my sensor mirror need cleaning?

[syar]

Sorry if this posted in the wrong section but couldn't see a better place to put it. Anyway I go my DLSR (Sony Alpha a200) about 7-8 months ago. Never had a problem with it and apart from wiping the lens and eyepiece, and the occasional blow out with a rocket blower I haven't needed to clean it. Yesterday however when I looked though the eyepiece I could see two dust marks. I cleaned the lens, eyepiece and I had a look at the senor (held it down so not to get any more dust in) and nothing. Photo's come out fine with no marks one it. I have tried both lens and its exactly the same.

The only thing I can think that it can be is the mirror. Now having never cleaned the sensor or the mirror I am kinda worried I might do something wrong, also i don't have any cleaning materials with me. I know I should do but that will change as of now. Do you think that my local camera store will clean or even show me how to clean the mirror? I have a few days off this week and I might go into my local town and take a few shots, I could then pop into the store and get some stuff to clean it. Do you think my problem is the mirror or could it be something else?

[RexK_Cozumel]

when you look at the mirror do you see anything on it? If you can see it in the viewfinder but not in the images then it is either on the mirror the focusing screen or inside the viewfinder itself. If it is really bothering you that much then you can clean the mirror, take the focusing screen out and clean that, or take the camera in to be cleaned.

[syar]

Well I have had a look at the mirror but I couldn't get any decent light on it. I'll have another look next time I have chance. How possible would it be that it's on the inside of the viewfinder? It doesn't look like it is. When I look though the viewfinder it looks like its on the end of the lens, but the lens is clean. thats why I am thinking its the mirror. I'll get some light on it and have a look soon. I'll have to go to the local store and let them have a look later on in the week

[Downy]

When I went to the camera store and asked, he told me the mirror I'm looking at through the viewfinder won't affect the shot. That's the mirror that lifts out of the way, so he told me not to sweat it. Shots come out good, so I figure he was right. Had him show me the proper way to clean my lenses also.