Bloody dust spots

[Grant]

I've tried to rid of 2 dust spots I can see through the viewfinder, and they WONT budge.

I've tried cleaning the viewfinder itself, and the mirror too, and yet still they havn't moved. It's most annoying.

Anyone know how to rid of these pesky things?

p.s. They don't turn up on pictures, and only through the viewfinder, so it definitely isn't on the Sensor.

 

[SDK^]

They might be on the focus box above the mirror

 

[Grant]

They might be on the focus box above the mirror

Now they're always out of focus, i.e. No matter what I adjust on the lens, they still stay blurred, I'm not too informed when it comes to how the camera works, so does this further cement your idea or not?

Cheers!

 

[CT]

You should be really careful of cleaning the mirror at all as they're usually surface mirrored and are easily permanently marked. It's highly unlikely to be on the mirror anyway.

The most likely location is the focusing screen itself. It's located above the mirror and sits at 90degs to the verticial axis of the camera forming the roof of the mirror box. If you remove the lens and look up you can just see it. I had a couple of similar spots myself, but have learned the hard way that you can make things worse by transferring more muck up there by trying to remove them. I ignored them and they're now no longer there so it smacks of just loose dust.

It's unlikely that dust has got inside the prism housing on the other side of the screen, which is the other possibilty. It's not unheard of for bugs to get in there though and even leave poop which becomes visible in the viewfinder.

Annoying though it can be I'd be inclined not to worry about it. The focusing screen is user removeable/replaceable on a lot of cameras but again you can do more harm than good with clumsy fingers.

 

[oldgit]

CT we've had a thread of this ... someone even did a better job of the artwork than me ( this was posted there), but I cant find the thread.

Focusing screens on Canons are ok to clean if you are careful, and only a few £10's to replace if you scratch em...