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Photography Question 
Irene Troy
BetterPhoto Member Since: 5/27/2004

Cleaning an SLR Mirror

Okay, Ive learned to clean my digital sensor thanks to the advice gained here and even know how to remove "welded junk". However, how do I get "welded junk" off the mirror? Everything Ive ever read or been told states in capital letters: Don't touch the mirror!!! However, there is this extremely annoying little black blotch on the mirror that refuses to go away. Ive hit with the rocket blower to no avail. I even got desperate and took a sensor swipe, wet it lightly with Eclipse fluid and very gently ran it across the mirror nope, the blotch is still there. Yes, I know, the blotch doesnt show on an image, but it is in the line of sight and drives me batty. In the past, Id have taken the camera to the shop and they would have used their power blower and all would be great. The camera shop closed last month Im still in mourning and the only other shop within 50 miles is terrible and I wouldnt let them touch my gear. The camera is a Canon 5D. So, anyone have any good ideas? Thanks, as always!

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9/16/2007 4:15:57 PM

Bob Fately   Irene - Don't touch the mirror! The reason is that you will undoubtably ruin it - unlike your household mirrors the mirror in an SLR is a front-surface type - that is, the microscopically thin reflective layer is a coating on the face of the glass substrate (your normal mirrors have the silver reflective layer underneath a protective layer of glass).
If this glob o' gunk is stuck on that well, you will need to send it in for cleaning. At least, it won't affect the actual images.

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9/16/2007 8:13:37 PM

Bob Cammarata
BetterPhoto Member Since: 7/17/2003
  I've read warnings about fiddling around with SLR mirrors and I just train myself to ignore those glitches that appear on my reflex mirrors and focusing screens that cannot be easily removed.
As long as my film is not affected, I try not to worry too much about them.
I've "coerced" a few stubborn specks off my mirrors and focusing screens with a dry Q-Tip but NEVER have I tried to remove the mirror to clean it off.
BTW ... Did you ever have a tiny bug get in there and start running around when you're trying to focus??
That can really be a hassle!

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9/16/2007 9:09:09 PM

Alan N. Marcus   Hi Irene,
Its true; SLR mirrors are of the first surface variety. This means the reflective surface is on top of the glass. Had the camera maker used an ordinary mirror with the shinny side on the back of the glass, you would see a weak but annoying secondary (double) image when you looked at a brightly lit subject.
Once upon a time, first surface mirrors were made by plating pure silver on glass. This made a nearly perfect mirror but silver is soft and tarnishes quickly. Modern first surface mirrors are vacuum plated aluminum. Not as good but time to tarnish is long-drawn-out.
Now opticians have a trick or two up their sleeve. A modern fist surface is over-coated with a super thin layer of clear transparent quartz. This over-coat reduces the fragileness of the first surface mirror. In fact, the surface is quite durable.
Now before you take a scrub brush and begin cleaning your first surface, you need to know that a SLR mirror is hinged as its movement is a fast up-down blink. Likely you will damage the gear train if you apply too much pressure.
Now if you are a brave soul, you can safely clean with most any lens cleaner. I use double distilled vodka (40% ethyl alcohol). An OK lens and mirror cleaner is a liter of vodka with two drops of liquid dish-washing detergent added. For a stubborn spot, try ordinary Windex on a Q-tip and polish with a well-washed T-shirt material as these are lint free. Should the Windex leave a streak or smear, follow with the vodka.
Cleaning of precision optical surfaces is not for the faint of heart. Chickens should stay far away.
Alan Marcus (dispenses questionable techno babble)

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9/16/2007 10:08:33 PM

Irene Troy
BetterPhoto Member Since: 5/27/2004
  Well, guys, thanks for the advice! Im trying to figure out just how far Im willing to experiment with removing this annoying spot. After all, the camera only cost me about $3000 and I have that in my change tray LOL! Bob, I once had a small fly die inside my old film camera. The fly flew in when I was foolish enough to set the camera down with no lens or front cover attached. I removed the corpse with a Q-tip that had been dipped in alcohol. Somehow, despite my lunacy, the camera survived and served me well for a few more years. But, I guess Ill either try Alans ideas or wait until Im in Boston and find a decent camera shop to deal with this annoyance. Thanks again.

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9/17/2007 11:09:19 AM

Steven A. Serpa
BetterPhoto Member Since: 7/22/2006
  Good Morning,

I would like to know how to professionally clean my sensor the camera is a Canon 20D.

I have never used anything but the air blower to clean it but I too have a few spots that always need healing in Photoshop to remove them.

So, if you have the correct procedure or if you can direct me to an article it would be greatly appreciated.


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9/18/2007 4:49:57 AM

Bonnie Berlin   are you sure it's not junk caught between the viewfinder assembly? I have a similar issue and my mirror is sparkly clean - cause i'm too stupid to be afraid of cleaning it!!!
the great camera shop that I sometimes use (they are about 3000 miles from me right now) said I needed to send it back to canon to get rid of all that junk. only when am I supposed to do without my camera for 3 weeks? and I also have the 5D. I guess it has a reputation for letting in the dirt.

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9/18/2007 5:14:28 AM

C, William Dunsay
BetterPhoto Member Since: 5/6/2005
  Canon, will clean for you if nothing else works or try them first. turn around is fairly fast. Plan on about a week to ten days. Call customer support.

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10/7/2007 3:32:44 PM

Amanda  M. Freese
BetterPhoto Member Since: 10/18/2007
  That's scary, I was once advised my Ritz Camera to take a lint free cloth and clean a light smudge I had on my mirror. .. I made sure to ask someone that I thought was a professional first and they turned out to be wrong? My camera functions fine, but who knows what I might have done to it anyway..

I used the edge of the cloth with my finger force. . do you guys think it's ok..?

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10/28/2007 5:23:40 PM

Irene Troy
BetterPhoto Member Since: 5/27/2004
  Amanda - relax! If your mirror still functions you did no harm. Long before I found this site and long before I got semi serious about my photography, I cleaned the mirror on an old film camera. I did not know that this was a bad thing, but the camera and I survived fot shoot many more images. No, you should not touch the mirror, but, well...let's just say that we all do things that we shouldn't. BTW: the spot on my mirror/whatever, remains, but I'm learning to live with it. If life ever slows down to the point that I can stand being without my camera for a week or longer, I might send it off to Canon.


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10/28/2007 6:01:34 PM

Amanda  M. Freese
BetterPhoto Member Since: 10/18/2007
  ok, thanks!

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10/28/2007 6:09:52 PM

Pete H
BetterPhoto Member Since: 8/9/2005

With basic precations, you should have no fear in cleaning the mirror.

I've cleaned mine more than once using "sensor Swabs" from "Photographic Solutions." They are simply sterile swabs with a little medical grade methanol.

Alan is quite correct in that modern day mirrors use a quartz overlay that is VERY resilient to scratching. Mirrors are also "annealed"..a thermal cooling process that further strengthens the material.

I am guessing you can actually SEE the dirt on the mirror? Some people mistakingly see a dust spot when looking thru the viewfinder. In this case it is usually the glass prism that has some dust on it, NOT the mirror.
If that is the case, one can usually blow it off with a air bulb.

You should clean the mirror. With every mirror slap, you run the risk of dislodging the dirt and eventually depositing it on the sensor..Not a nice thing.

I think all these warnings we read about cleaning the sensor, mirror etc are overblown and probably designed to generate more income for the camera companies.

DSLR dirt is a fact of way around it.

all the best,


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10/28/2007 6:14:29 PM

Irene Troy
BetterPhoto Member Since: 5/27/2004
  Thank you, Pete! I definitely agree that the issue of whether or not the user can clean the camera sensor is totally overblown! So many people seem to think that one must have an advanced degree in engineering to complete this fairly simple task. Personally, I was initially a little scared about cleaning the sensor on my first digital SLR; however, after the first time I failed to see what the big deal was about. When I got my Canon 5D I had a moment of should I or not but, again, once done the first time, it has become merely another routine item on my check list. I end up having to clean the sensor about once a week. I use a rocket blower, Artic Butterfly and PS swabs with Eclipse fluid and have never had a problem.

I did wonder about the mirror cleaning business as I said above, I did clean the mirror on my old SLR and did not hurt anything. I have used the blower on the mirror and even the swab with the Eclipse fluid, but the spot remains. I read the part about the dust maybe being in the glass prism and wonder if this is my problem. I have used the rocket blower at just about every angle without noticeable success. Im rather resigned to the spot remaining as a part of the camera.

Most of my photography takes place outdoors, often in fairly dirty and even wet conditions. I actually purchased the 5D because, as a pro level camera, it is very tough and designed to hold up in adverse conditions. I am reasonably careful using lens hoods all the time but, dirt, dust and even unwanted moisture is simply a fact of life in my type of work. Thanks again for your info!


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10/29/2007 6:00:13 AM

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