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12-11-2006, 06:12 PM   #1
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cleaning the focusing screen

ANy steps/tips on how to go about cleaning the focusing screen/mirror.

i had a spec on it, and i tried blowing it off w/ the a brush blower but somehow i made it worse..now i see a few more marks when i look through the viewfinder...

rather annoying...it's not on the sensor...

TIA

12-11-2006, 08:24 PM   #2
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QuoteOriginally posted by -=JoN=- Quote
ANy steps/tips on how to go about cleaning the focusing screen/mirror.

i had a spec on it, and i tried blowing it off w/ the a brush blower but somehow i made it worse..now i see a few more marks when i look through the viewfinder...

rather annoying...it's not on the sensor...

TIA
That sucks, JoN!
I can't help you but I hope it is fixable.... I think I am going to be afraid to try to even attempt things like this..... but I know my day will come

good luck, let us know how you make out

randy
12-11-2006, 08:45 PM   #3
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I have some dust particles and what looks like a little dead ant in my viewfinder. First, I thought that the lens is soiled from inside. Thankfully, it's not. I tried cleaning it, but just like you, succeed at introducing couple of more particles .

Now, I've learnt to live with it. However, if anyone has cleaned the VF and mirror successfully, I'd never shy from giving another try...
12-11-2006, 10:11 PM   #4
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Just be carefull its very fragile...

It may also be on the underside of the prism, so when you take the screen out give a little blow (with your trusted blower) inside the camera too (where the screen was)..

12-12-2006, 04:53 AM   #5
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Cleaning the underside of the focusing screen - top of the mirror box - is just ok if you clean it VERY delicately - reason is that it is finely textured plastic and any noticable force will leave permanent scuff marks.

A very light touch with a CLEAN synthetic brush (I use carefully multi washed make up brushes) to dislodge a dust particle is ok - I use the cleaning method shown here The Pixel Sweeper including air blowing using a foot operated air mattress inflator for controlled pressure.

I got caught with a tiny bit of detergent residue on one of the brushes and found I could easily remove it from the focus screen with a Kleenex tissue that I folded to a point (do not touch the tip because of skin oils) and just dipped the point in clean water and then touched it to another tissue to leave the tip just moist - stroked it across the spot where the brush smear was and the screen was absolutely clean.

In any cleaning of this area try to do it with an air stream (NOT canned air IMHO) and if you must touch anything to the screen be very gentle as it is sensitive to pressure damage which is absolutely permanent.

NOW - the MIRROR!! any dust on here will not affect the image and will be invisible in the viewfinder as it is not on a focus plane.

For the anal retentives who can still see dust on the surface and are worried by it, clean compressed air is THE ONLY THING that should ever be used if you want to have the mirror reflecting at 100%

Reason - it is a part reflecting mirror, as most of the light goes to the viewfinder and the metering sensor BUT some goes straight through the mirror to be reflected downwards by a second mirror on the back of the main mirror to the focus sensor which can be seen on the bottom of the mirror box. If you scratch the incredibly fine metalised coating on the main mirror you affect the viewfinder, metering and focus - I suggest it is best to leave it alone as much as possible.

Rod

REFERENCES -
The Pixel Sweeper
Cleaning Digital Cameras - Introduction
CCD / CMOS Cleaning Photo Gallery by Nicholas R. at pbase.com
http://www.kodak.com/ezpres/business/ccd/global/plugins/acrobat/en/supportdo...CoverGlass.pdf
12-21-2006, 08:10 AM   #6
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I took my new (as in factory fresh) lens and k100d body, went into a sealed, low humidity, filtered computer room – (the closest thing you can get to a clean room), did the fast switch - took the white cap off of the camera body and mounted the 50mm 1.4 -- and low an behold – after looking through the viewfinder noticed a black fiber in the viewing area.

I took off the lens, and could see a speck of dust on the grey, angled viewfinder screen(?)in the body of the camera (white dust appears black…).

The sensor does not have dust -- I took out of focus shots at f/22, and a bunch of other shots and the photos look good.

The fiber is clearly visible when looking in the viewfinder, about 1/3 the width of a focus line, but it doesn't bother me a bit. My only concern is that it will migrate to the sensor or some crevice of the camera where it will wreak havoc.

Should I leave it alone? Use the blower? Any other suggestions?
12-21-2006, 08:25 AM   #7
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QuoteOriginally posted by superfuzzy Quote
I took off the lens, and could see a speck of dust on the grey, angled viewfinder screen(?)in the body of the camera (white dust appears black…).

Should I leave it alone? Use the blower? Any other suggestions?
the "grey, angled viewfinder screen" is the mirror that allows you to view the same image the lens sees. It has no effect on the actual image itself. Take a bulb type blower, and with the camera pointing down, gently blow it out. It will be fine. Do NOT use compressed air, as you could spray some propellant into the camera.

A Giotto Rocket blower seems to be the most popular type of bulb blower. I use one and it works great.

Cheers
-Alan
12-21-2006, 09:01 AM   #8
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Changing/Cleaning the Focusing Screen

Removing the screen to replace or clean is relatively easy . . . see the attached document. Please excuse the quality of the pics . . . did this in a real hurry. Hope this helps.

12-21-2006, 09:53 AM   #9
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Where is the attached document? Thanks...

QuoteOriginally posted by rprii Quote
Removing the screen to replace or clean is relatively easy . . . see the attached document. Please excuse the quality of the pics . . . did this in a real hurry. Hope this helps.
12-21-2006, 10:13 AM   #10
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Believe it or not: wash it! (If it is really dirty and if you can not clean it with compressed air.)

This is how: rinse the screen first (to get rid of larger particles that could scratch the screen), have some soap on your thumb and index finger, rub gently both surfaces between your fingers. Then rinse thoroughly (avoid touching the screen, not critical but may help) and let it dry on air. Compressed air or hair dryer at low setting and not to close helps to dry it within seconds. Do not wipe with anything! Don't use any abrasive cleaner of course. Be careful not to drop the screen on anything hard or sharp and make sure you'll not wash it down the sewer by chance. That's all. (Tested and it works.)

The physics behind it: focusing screen is just a piece of plastic with matte surface. Touching it with any paper towel or cloth will just push dust deeper into the micro structure or help larger particles grip it and stay there. Cleaning with the brush blower does the same, pushes dust in. Cleaning it with soap and water will free surface from anything sticky that may be holding dust and will let water molecules carry dust away (they are much finer than any brush!).
12-21-2006, 10:34 AM   #11
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Changing/Cleaning the Focusing Screen

QuoteOriginally posted by superfuzzy Quote
Where is the attached document? Thanks...
Sorry, just realized that the word doc had exceeded the, very small, allowable size. Let's try it this way . . .

Inside the body you will see that the screen is inside a black metal frame . . . at the top of the frame is a small tab . . . press on the tab and the screen will drop down. you can then remove the screen for cleaning/replacement . . . when done, simply push up on the frame until it clicks into place.
Hope this helps

Last edited by rprii; 05-12-2007 at 05:29 PM.
12-21-2006, 10:38 AM   #12
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now...how will one take out the screen (sorry, both my previous bodies had or has unchangeable screens)

edit....just saw rp's post....thanks...
12-21-2006, 11:06 AM   #13
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QuoteOriginally posted by -=JoN=- Quote
now...how will one take out the screen (sorry, both my previous bodies had or has unchangeable screens)

edit....just saw rp's post....thanks...
I can only speak to the models I have (*istDS & K10D) . . . after the screen drops down, you can easily remove the screen from the mounting . . . do not worry about how to put it back because it is notched so that can only be inserted one way. I would assume that all models with replaceable screens are built the same. with tweezers, etc. or, tilt the body and it should drop out into your hand.
12-21-2006, 11:21 AM   #14
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I have a k10 also, so...it should be the same. was thinking of picking up another focusing screen too, so I might tackle that when I pick that up.

thanks for the info
12-21-2006, 12:28 PM   #15
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Yup, it is the same on the K10D. Mine had what looked like a odd-shaped chip of glass in the viewfinder when I took the 1st look through. A quick examination confirmed a "grey spot" on the non-exposed side of the focusing screen. My initial thoughts were damage to the prism, it looked so much like a glass chip!.

Anyway, found a soft'ish plastic utensil, and pushed the clip in carefully, until the frame holding the focusing screen fell away.. the screen actually almost fell out of the body. The dust spec fell out with it, so tweezers to replace the screen, and raise the frame clip back up to lock.

Easy to do, but kinda scary to a newb.
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