Something lurking in my viewfinder..

Dreadhead · 17 Mar 2013 at 21:22

Hello there,

Recently I noticed two small brown marks in my viewfinder of my Canon 600D.

These don't show up on my photos, so I assume are either on the focusing screen or somewhere else in the viewfinder path.

Oddly they both look very similar, almost akin to a oil spill. I thought maybe due to the patterning on the marks it could be some sort of grease or even a spore growth. I really have no idea how these have appeared. I keep my kit clean and dry in my house, protected in a large bag. I am also quite careful when changing lenses.

I have tried to capture an image using my phone. Can anyone offer any advice on how I can remove these?

My Canon is still under warranty till the end of this month, I assume if it is just dirt then I have to deal with this myself.

Raymond Lin · 17 Mar 2013 at 21:35

Open the lens cap, look inside and up, do you see those marks on the focus screen?

If it is, you can replace it.

Dreadhead · 17 Mar 2013 at 21:56

Hmmm, I have just done so and cannot see the marks.

I assume I am looking at the correct part. Is there a way to detach this without causing it damage?

Raymond Lin · 17 Mar 2013 at 22:00

I take it there is nothing on the mirror?

Dreadhead · 17 Mar 2013 at 23:07

No, nothing that I can see on the mirror. Both the mirror and the focusing screen look very clean. Could the marks be in the cavity just behind the viewfinder glass?

a1ex2001 · 19 Mar 2013 at 14:44

I would ignore them had similar in my 30D as long as I owned it and it never did any harm.

Even if you remove it you will likely get more so start the endless cycle!

hyperst · 19 Mar 2013 at 14:46

I would use the warranty while you can.

mrk · 19 Mar 2013 at 22:26

Eerily they don't look too different to the circles that were on my Sigma lens front internal element!

Andy90 · 21 Mar 2013 at 15:47

Raymond Lin said:
Open the lens cap, look inside and up, do you see those marks on the focus screen?

If it is, you can replace it.

Raymond, not every Canon Camera has a user replaceable focus screen.

According to the Canon Manual for the 600D, the system map doesn't show interchangeable screens for that body (page 276). You can obviously get replacements via Canon or other service centres, but looking at the pictures supplied by the OP there isn't a metal retaining clip to unlock the focus screen frame.

There are a number of locations for spots of dust/oil etc. to reside which will show up in the viewfinder

1) Mirror surface
2) outside facing surface of the focus screen
3) internal facing surface of the focus screen
4) the outside facing surface of the focus dot screen (a transparent layer behind the focus screen)
5) the inside facing surface of the focus dot screen
6) Any of the surfaces of the pentaprism or pentamirror assembly

Those dots however look like they might be a liquid since they look like they're exhibiting Newtons Rings

It might be some oil deposited within the camera from within. If the Camera is within Warranty it may well be worthwhile ringing Canon and seeing if they will clean it free of charge.

Whatever you do don't go poking around inside, you will only end up with more smears/spots etc. on the focusing screen than you started with.

You can find the Canon Repair centres at

http://www.canon.co.uk/Support/Consumer_Products/services_locator/index.aspx

Just select Digital SLR from the drop down

The Official Canon Repair Centre at Elstree are brilliant (they're right at the bottom called Canon (UK) RCC), I've used them myself and their turnaround is very good.