T3i focusing screen help please.

So I had a hair on the focusing screen of my camera, it was annoying the heck out of me, trying using my blower on it, then tried something else and so on, read instructions on removing re-installing etc..

Anyhow, I have really messed it up. scratched it, don't get the red dot anymore. pretty sure it is seated in there properly...

So what now ?

shutter count is just over 40,000
doesn't seem worth sending into canon, new t3i bodies are about $450, I'm thinking it will probably end up cost more than 1/2 that to send it in,
should i order up an ebay focusing screen for it ? i have made my mistakes now, 90% sure I will do the next one right..

But most importantly:
will the camera operate and focus correctly with a damaged screen ?
i have taken several shots, they all seem to be in focus, Seems to work fine in live view.
What does the focusing screen do, is it just for the user to see what is in focus or does the camera actually use it?
I rarely use manual focus, my eyes are shot..
there is still a confirmation beep, when camera locks focus..

i want to upgrade to the 70D, but timing is not great,

Sounds like a new screen will fix it. If that's he case it's worth fixing. I was obsessed wih dust and particles on the screen and found oh the more you blow, the more crap is introduced. Just get it fixed and leave the specs and crap alone.

I have a T3i and just bought a 60d last week. It was on sale at b&h for $599. Seems to be a real nice camera

The standard focusing screen in a dSLR is largely a useless tool for evaluating focus...it is deliberately made bright because the reflex mirror lets about half the light through to the AF sensor in the bottom of the camera. As a result, it is much less precise than film SLR focus screens. Not that film focus screens are all that terrific, when you ignore the presence of a focus aid in the center of the screen! I have a Topcon Super D, the first TTL SLR on the market, from 1963. With its f/1.4 lens and center focus aid, it is extremely precise. But if I use the surrounding groundglass focus area instead, focus can be off by several inches, even if I focus very close (6-8' away) were DOF is inherently very shallow. And the dSLR focus screen is even worse that that!

A hair on your focus screen (or even a damaged focus screen) does NOTHING to affect AF precision. And given the inherent error of any bright focusing screen without a focus aid in the center, it also does nothing to your ability to manually focus. It is merely a distraction to someone looking into the viewfinder.

Thanks for your advice, I suspected that the focusing screen was just for the viewer and not really needed for camera operation, I did not think that a hair would affect precision, it had been there for a while and today was the day I was feeling particularly annoyed by it.

i will just order up a new screen, maybe two

The T3i does not have a focus screen which is designed to be normally changeable by the user. With proper instructions, it can be done, but not as quickly as a 60D or 5DII.

If you can remove the existing screen, it is a simply matter to pour distilled water over both surfaces, let stand on edge to AIR DRY (no wiping the textured surface!!!) before reinstallation. No need to buy a new screen at all.

Wilt wrote in post #16277610
If you can remove the existing screen, it is a simply matter to pour distilled water over both surfaces, let stand on edge to AIR DRY (no wiping the textured surface!!!) before reinstallation. No need to buy a new screen at all.

the screen is easy to remove and re-install.
Don't under estimate how much I, hmm, lets say' "messed up" the screen. i am normally very good at repairing electronics of any type, have been doing it for many years,..this one went all wrong..
Thankyou very much for the advice I will keep in mind for next time, I had no idea how sensitive the screen was, I will try the distilled water method, just to see how it works out..but it probably wont fix the scratches from using tweezers..

found one on ebay and ordered it up...

here's a link
http://www.focusingscr​een.com/work/600den.ht​m

Try not to touch the new screen at all. If handling it with your fingers, only touch the edges. The interchangeable screens come with plastic tweezers designed to fit a little tab on the edge, to avoid touching the main part of the screen. Those screens are very easily damaged.

You also mentioned "Not getting the red dot anymore"... that concerns me more. By any chance, have you got the focus set to AI Servo or the mode dial set to "sports", which also would select AI Servo focus? There is not red "focus confirmation" flash when the camera is using AI Servo, though you should still get the initial "focus start" red flash. It also might behave this way if focus is set to AI Focus and the subject is moving (in which case the camera switches to using AI Servo).

Hopefully you haven't done anything that would cause problems with the focus start/confirmation flashes of the selected AF point... It seems unlikely, too, since it's not part of the focus screen itself. It's done by a display above the screen.

I don't know what you paid for the focus screen on eBay. But typically a focus screen ordered directly from Canon isn't very expensive (usually $25-45, depending upon camera). I believe the part you need is CY3-1621.

No, I don't think it wouldn be expensive to have Canon repair it, either. Besides the cost of the part, the shipping to and from Canon might be more than the labor charge. If you are at all uncertain about repairing it yourself, send it in or look for a local camera repairer. It's really a fairly fast and easy job... they might only charge you a half hour labor if you supply the part. They might give your camera a good checkup and cleaning, too.

I have tried it on all 3 focus settings, when i tried in the dark I could see a red flash at some random spot..I am not too worried aboutit, I use the center focus 90% of the time and I still get the confirmation beep...

Thanks for the part number, i looked at some of the retailers like B+H and the local guys, I couldn't find a screen, i did not think of going direct to canon...next time I will check there first..

I will try again myself, up in here in Canada, everything that should be easy is usually a pain in the butt, like sending it to canon..and costs twice as much as it really should.
i will just keep using it as is, until I can afford either the 70D or the 6D..and then I will have a spare camera...

I would just fix it if everything else works. I like the T3i for some reason.

Same part number:

http://myfriggincamera​.com …_44_47_51&produ​cts_id=200