heavy dust inside my focuser :(

pierce

i have a 350D aka rebel xt thats treated me very well, taken 25000 or 35000 pictures (I've lost track how many times the photo number has wrapped around), but of late there is a LOT of black spots in the viewfinder and they are starting to annoy me. I'm pretty sure they are on the top side of the focuser screen, as attempts to move them around with canned air (yes, I know the caveats, and I know how to use it properly) have proven futile.

has anyone attempted to take off the top of the viewfinder on an EOS Rebel X(R/T/Ti/etc) to clean in there? I assume I'd have to remove the popup strobe and somehow get under the prism (or is it a mirror box?). I have jewelers screwdrivers and such. I see some screws on either side of the viewfinder, and it appears the top including the pentaprism cover w/ the flash is a seperate piece of plastic.

ziggy53

Dust that is visible only in the viewfinder is likely on the viewfinder screen. The viewfinder screen is located inside the mirror box at the top of the camera. Cleaning involves the removal of the viewfinder screen and risks damage to the primary mirror. (The primary mirror is a front-coated mirror and may be easily scratched.)

Repairs to the mirror usually involve replacing the entire mirror box assembly, often around a $250-$350USD affair (for the XT/350D). If they replace the mirror box they may also replace the shutter assembly at the same time, raising the cost to around $350-$450. Are you sure you want to proceed?

Alternatives include taking/sending your camera to an authorized and capable service center where they can perform the cleaning at much less cost than the potential damage you can incur. You could also have an improved viewfinder screen installed for a $65 service fee (plus the cost of the screen itself.) In that case you might look at Katz Eye screens:

http://www.katzeyeoptics.com/item--Installation-Services--prod_install.html
http://www.katzeyeoptics.com/item--Canon-350D-Focusing-Screen--prod_350D.html

(Note that I neither use nor recommend Katz Eye screens, but we have some users who are pleased with their's.)

pierce

yes, i'm quite sure its on top of the focusing screen, as these dust particles are in sharp focus in the viewfinder. the mirror looks fine (and even if there's a bit of dust on it, its out of focus in the viewfinder).

I was asking if anyone has done this sort of repair themselves, how difficult opening/removing the top of the camera might be, or if it has to come out the front of the camera (seems less likely from my examination).

I've had cameras in the past that had removable/replacable focuser screens (I believe the Pentax MX 35mm SLR that I had in the late 70s was of this design), but obviously, the EOS 350D isn't readily replacable.

ziggy53

OK, if you still want to clean it yourself, the link I listed above that relates to the replacement screen from Katz Eye has a DIY instructions for replacing your own screen and you can use those instructions for "cleaning" your own screen.

In addition to their instructions, which I haven't read in a while, I suggest you also locate a lens grade microfiber cloth to cut and place over the mirror during your removal of the screen. This can help prevent scratches on the mirror but you still need to careful.

pierce

oh wow, so the focuser screen *does* lift out. thank you, that makes life MUCH simpler.

gryphonslair99

ziggy53 wrote:

OK, if you still want to clean it yourself, the link I listed above that relates to the replacement screen from Katz Eye has a DIY instructions for replacing your own screen and you can use those instructions for "cleaning" your own screen.

In addition to their instructions, which I haven't read in a while, I suggest you also locate a lens grade microfiber cloth to cut and place over the mirror during your removal of the screen. This can help prevent scratches on the mirror but you still need to careful.

You tried.