Dirt in viewfinder, HELP!

[Jwreich]

I taking some pictures this afternoon and notice a black spec just beside one of the AF points in the viewfinder. I try to clean it off myself but only get a fiber on the viewfinder.

I call the camera store and they tell me to bring it by, they will help clean it off. This is located in the shutter area, behind the lens on the VF. At the camera store, he blows it off with canned air and that appears to blow some more "stuff" on the VF area...

I think I've taken about 4000 shots since buying my Rebel XT 5 weeks ago. The guy in the store proved the sensor was fine and therefore my pics were fine, but when I look in the VF to frame a shot I have faint little black specs.

The guy at the store wondered if the foam padding for the mirror was the issue. I don't know, but the "stuff" is now on the inside of the VF housing where I can't get. The canned air seems to blow it around, but not out...

This does not appear to hinder my pictures. What should I do? Send it to Canon and wait 4 - 6 weeks for a cleaning, find a local repair shop to clean the camera or live with it and shut up?

Thanks for your suggestions.

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[shiato storm]

could be the focusing screen...if you take off the lens, and look above the mirror - the way the light goes to your eye - you'll probably see a small screen, usually this is a matte/semi-opaque screen that may have etching on for focusing aid. it could have got between this and the viewfinder/prism mirror...do a check as I think in some cameras this focusing screen is fixed in place, in many (most?) models its possible to replace the focusing screen for custom jobs i.e. macro screen has a grid. before you messing around inside the camera too much though make sure your camera can give you access to the screen as - since you've tried all other avenues - this could be what it is.

[Jwreich]

Shiato,

I do believe you are correct. The "stuff" is between the focusing screen and the VF. The mirror is clean as well as the sensor. The images are all nice from what I can tell, but I SEE the black "stuff" in the VF.

I don't know if I can pull the screen out, but I don't think I would want to try this.... Any suggestions.

[britain]

I too have same issue , with new 20D straight out of the box.:evil:

[Jwreich]

Wow Britain,

At least I had mine for a while. I just when to Wal-Mart and got some canned air to give it a try for myself. Wish me luck!

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[britain]

Kmart compressed air? Dont they own Sears now? Unfortunatly where I bought the camers is a few hundered miles away....:cry:

This ones very dirty and I'm not a happy camper...its like having poison ivy itch...irritating! Let me know if it works!!

I may do the same..

What the chance of this dust or particles going some place more damaging??:eek:

Good luck !!

[Jwreich]

Better news.... After some very careful work with a can of air I have been able to move a good portion of the "stuff" from the focus assist screne. I still have a few black specs, but not as many as after my trip to the camera store.

I know a simple removal of the "screne" by a repair shop would have it clean as new, but as long as the images from the sensor are clean I'll be happy for know. I've never owned a SLR camera before so I don't know how usual this is for this type of camera.

Regards,

[britain]

I think perhaps I'll try the same untill I can get the camera back to SD. I want to make sure there is no fungus growing it it. :)

Most of of the shots I'll be taking will be in a dirty dusty conditions, must learn how to clean it.

Only picture I've taken is a white wall with several different lens to be sure that the junk is not on the cmos...seem to have one criminal spot....

[buze]

I have dust on the mirror/af screen on a regular basis. Only cleaned the sensor twice (with compressed air) but the mirror it's very common. I use the same brush I have for the sensor to clean it. Not only the mirror you can see, the one at the too of the body too. I brush a little too loosen them up, then give it a compressed blow -- all of that with the camera over my head pointing downso the specks don't fall back in!

[Jwreich]

What the chance of this dust or particles going some place more damaging??:eek:

Good luck !!

Well the only place I can think they would make it worse is if they made it on the sensor. The funny thing, You can buy a kit at most good camera stores to clean the sensor's, they are easy to get to under the mirror.

Does the 20D have a pop up flash? The XT does and knowing these cameras aren't air tight, I blew air through the little hinge openings for the flash. This helped to move some of the dust out of the camera.

[dsze]

1. NEVER use compressed air or blow with your mouth on your sensor, use a hand blower.

2. NEVER touch your mirror with ANYTHING except air from a hand blower.

3. Who cares if there are dust specs on the VF as long as there isn't so much that its blocking your view? ;) They don't effect the images your making.

-daniel

[buze]

They obviously affect the autofocus system, since it's it's own view of whats happenning. As for compressed air, if you are careful to hold the can perfectly vertical, and give a few "empty" very short blows to remove anything from the tube, it works, it's clean; I tested that many tines by blowing it on a UV filter (which are REALLY good at displaying *any* form of residue)

And why not touch the mirror ? I mean, people touch their sensors to clean them, and the mirror is nowhere near as sensitive.

Seems there is lots of really wierd urban legends about this and that floating around. The rule should probably be "think, and be very careful" but leaving junk on the mirror in fear of touching it a very wierd concept!

[KennyG]

They obviously affect the autofocus system

They do not affect the AF system. AF does not follow the same path as the VF. Dust on the mirror could affect AF however.

You can easily tell if dust is behind or in front of the focus screen. Keeping the camera still look into the VF and move you head very slightly. If the dust moves in relation to the etching on the focus screen, it is behind it, if it moves with it it is on the front of the screen.

[dsze]

They obviously affect the autofocus system, since it's it's own view of whats happenning. As for compressed air, if you are careful to hold the can perfectly vertical, and give a few "empty" very short blows to remove anything from the tube, it works, it's clean; I tested that many tines by blowing it on a UV filter (which are REALLY good at displaying *any* form of residue)


Nope... as KennyG said. Dust on the mirror is easily blown off in most cases with a hand blower. And why take a chance on canned air? Why take even the smallest risk of blowing something other than air onto those delicate parts? ...just doesn't seem worthwhile to me. I've also read/heard that the force of canned air can actually cause more damage by forcing dust particles into worse places. I bet your owners manual states very clearly that you should use a hand blower and NOT canned air (not that the owners manuals are always correct) :lol:

And why not touch the mirror ? I mean, people touch their sensors to clean them, and the mirror is nowhere near as sensitive.


Nope, wrong again. The mirror is much more sensitive to touch than the filter that is being touched directly in front of the sensor.

Seems there is lots of really wierd urban legends about this and that floating around. The rule should probably be "think, and be very careful" but leaving junk on the mirror in fear of touching it a very wierd concept!

Right! There are alot of wierd urban legends floating around. However, I think you'll find the consensus to be that canned air and touching mirrors should be avoided.

If you believe my statements to be urban legens, please do enlighten me. I may be incorrect. Do you have something that states using canned air/touching mirror is recommended and/or that dust in the VF effects AF?

-daniel

[britain]

Hummm, Good info..This time for me, I'll just take the camera in for service. Once warrenty is NG I'll go in clean it myself.

[Jwreich]

When the camera store pulled out the compressed air, I decided I could do the same. So far so good...

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[britain]

Actually got to use the camera today, the particles in the VF are a pain but what a great camera!:) :) :)

[buze]

Right on Jwreich! Compressed air is a tool, it has several uses. I've been using compressed air for about 20 years; you can do amazing things with it. Like, I can cool down a component by holding the can sideway, or blow dry clean air etc.
Oh, and you need to know how to position the tip to create a small vortex that leads the particles out, etc.
All in all, it's a tool. Like a hammer, you can break all kinds of things with a hammer, but you can also do lots of delicate things with one.

The operating manual discourage use of tools that *might* be bad in the wrong hands, and rightfuly so.

[summerwind4]

compressed air is also what i use, but i would never recommend it to anyone, especially if i don't know them.
the hand blower is really the safe bet, but can also be the contributer of more dust. it has to get air from somewhere right?............and just what is in the air?
with compressed air though you have to use a lot of common sense and NEVER use a brand new can. i always pick one (i keep several going for my needs) that is 1/3 or less full for any internal blowing, and even then i take test shots at something to get the feel of how much force is coming out of the can to determine the distance from the sensor. it doesn't take much, and it's only going to remove obvious pieces of junk that are showing up.
but this works for me, and with mechanical background it makes it easy for me.
for some though, canned air is a natural disaster.

[2112]

Ya, I just noticed a black spec thru my viewfinder today :( Its not on the lens and when I have no lens attatched, I can still faintly see it. It doesnt show up in any of my pictures though, so does that mean its not on the image sensor? How do I find out where it is?

[bolantej]

my understanding is if you can see it in the viewfinder, it's either on the mirror or on the focusing screen. you cannot see it if it's on teh sensor uintil you view your image on a monitor. take off the lens,and look at the mirror and focusing screen to try and locate the dust.

[Jwreich]

If it isn't on the pictures, it's not on the image sensor. Good for you. I found a local repair shop that cleaned the focus screen for $5.00. Now I have clear vision.

[buze]

Actualy it seems to be a tad more complicated than that. The mirror that you see when looking in the camera is partly tranparent, there is *another* one, smaller, behind it.

The light you see in the viewfinder is from the first mirror (mostly) and the second mirror gets it's share of lignt *trough* it to direct it to the AF.

So if the Focus Screen is dirty, it doesn't affect the AF. If the first big mirror is dirty, you will see some junk AND it will affect the AF by transparency; and if the second mirror is dirty, you won't see anything but your AF will be totaly bonkers. And it will affect your pictures indirectly, since the AF might be off (and will definitly hunt at the slightest problem)

To see if your second mirror is dirty, *very gently* fold back the main mirror and look behind. Some time ago I discovered I had all kind of junk on that one, and that was really ruinning plenty of my shots since the AF was hunting and sometime was totaly incapable of focusing....

Clean with even more care than the sensor !

Junk is everywhere !