Whoops marked my viewfinder with a rocket blower. Help please!?

Hi Guys,

This morning my rocket blower arrived and I couldn't wait to try and remove a couple of bits of dirt that have been visible through my viewfinder on my 400d. As I was probing around inside the body, the end of the rocket made light contact with the clear material that has the autofocus pattern on and an almost finely ridged surface. To my horror when I now look through it, there are three quite distinct light smear or scuff marks. :O Does anyone know how I might be able to rectify the situation? It seems almost impossible to believe I could have done any permanent damage, so light was the contact. Grrrrr, or at worst how much a rufurb would be? That's a serious lesson learned!

The good news is that it won't affect your images. I don't know it the focus screen is replaceable on the 40D but that may be your only cure. You can try to clean it carefully with a pec pad and some eclipse (not sure if this is safe so do your homework).
Anyway, if it fails, here is a link...
http://www.katzeyeopti​cs.com …ing-Screen--prod_40D.html

meady100 wrote in post #5395708
Hi Guys,

This morning my rocket blower arrived and I couldn't wait to try and remove a couple of bits of dirt that have been visible through my viewfinder on my 400d. As I was probing around inside the body, the end of the rocket made light contact with the clear material that has the autofocus pattern on and an almost finely ridged surface. To my horror when I now look through it, there are three quite distinct light smear or scuff marks. :O Does anyone know how I might be able to rectify the situation? It's seems almost impossible to believe I could have done any permanent damage, so light was the contact. Grrrrr, or at worst how much a rufurb would be? That's a serious lesson learned!

thanx for posting. you may spare someone else from doing the same thing.

ed rader

You have probably marked the underside of the focus screen. They are interchangeable though difficult for users to clean. I would take it to be service cleaned. If you have damaged it you can buy spares and they come with instructions and a tool for the job.

It's supposed to be easier for the user to replace than my 30D screen, and that was easy. The Katz Eye site has detailed instructions - looks the same to me as for the 30D: http://www.katzeyeopti​cs.com/files/40D.PDF

A new screen from Canon is pretty cheap according to those who have gotten one. A few dollars...

EDIT: oops, you said 400D and I read 40D. Here's the link to the 400D instructions:
http://www.katzeyeopti​cs.com/files/400D.PDF

-js

Thanks people. It could have been a lot worse I guess. I'll give cleaning it, or replacement a shot. Last time I go *near* that thing!!

Take out the focusing screen before you attempt another cleaning.

I did the same exact thing. Fortunately when I sent it to Canon they cleaned it for me.
But afterwards I bought a Ef-d focusing screen and found out that the focusing screen is pretty easy to remove (provided you have the correct tool). You should remove it first before you do any new smears on other parts of the camera especially the mirror.

If it were mine I'd take the screen out and have a close look at it. It's probably not scarred, just some goop from the blower nozzle on it.

Washing in dilute liquid dishwashing detergent, rinsing under the tap and air drying couldn't possibly damage the screen. It's made of plastic, not gossamer...

-js

EDIT: this is true on a 40D (or 20D or 30D) but not true for the 400D. See post #12.

Oops, you said 400D and I read 40D. Here's the link to the 400D instructions:
http://www.katzeyeopti​cs.com/files/400D.PDF

Looks the same as for my 30D except for the multiple shims.

If you're not comfortable with an operation of this delicacy any camera repair shop should be able to do it in 5 minutes...

-js

so...whats the recommended way to get rid of spots in the viewfinder?...or do you just deal with them...they don't show up on my shots...just curious as i've first noticed a couple a few days ago...i have a rocket blower...just afraid to do anything wrong

number six wrote in post #5395873
Washing in dilute liquid dishwashing detergent, rinsing under the tap and air drying couldn't possibly damage the screen. It's made of plastic, not gossamer...

Except that this is a Digital Rebel focus screen. The focus screen on the DReb series (300D, 350D, 400D, 450D) have tiny stick-on reflective dots for the red AF LEDs. Those dots come off very easily, and then you don't have the AF LEDs any longer.

meady100 wrote in post #5395708
Does anyone know how I might be able to rectify the situation?

Probably not. You'll probably make things worse.

Focus screens are easy to smear, and very hard to unsmear.

Nobody bothers to refurbish them. They're dirt cheap brand new. I think I read the other day someone paid $2.61 US for a replacement screen for a Digital Rebel—I don't know what the price is in India. The part number that you need for the XTi/400D is YN2-3580-000. You'll probably pay more for shipping from Canon than for the screen itself, so I suggest that you buy more than one.

Doug Pardee wrote in post #5396262
Except that this is a Digital Rebel focus screen. The focus screen on the DReb series (300D, 350D, 400D, 450D) have tiny stick-on reflective dots for the red AF LEDs. Those dots come off very easily, and then you don't have the AF LEDs any longer.

Geez. I started out thinking 40D because I misread the OP, now I'm giving bad advice.

I'll edit earlier posts...

-js

This is great help. It's a relief others made the same mistake. Gosh, I was wondering how the screen managed to light up. Reflective! I'll see if I can take it out anyhow and assess the damage. Thanks especially for the link Number Six - it looks pretty scary, but I'm excited to give it a try. This is a great forum