Cleaning the focusing screen

lhoff601 · Sep 2, 2014

I have a Nikon F3, with a focusing screen that has some particles that the brush on my Lenspen will not dislodge. I'm not sure what more there is that I can try, that won't badly scratch the screen.

How would you clean this focusing screen, if it were yours?

Thanks!

zanxion72 · Sep 2, 2014

Try removing the focusing screen and submerse it in lukewarm water with plenty of dish washing liquid. leave it there for 10 minutes and then take it out, rinse it and that's it. Do not rub it or you may damage the Fresnel surface.

F4user · Sep 2, 2014

With compressed air from an oil free compressor ( teflon rings ) ... like stomatological grade.
Comercial spray with compressed "air" in fact buthane have traces of oil. I don't like it even for dust cleaning of a computer.
Usually I do not want to touch any optical surface glass or plastic.
[ joke ] Visit your dentist [ /joke ]

Xmas · Sep 2, 2014

ignore

lhoff601 · Sep 2, 2014

Thank you!

AgX · Sep 2, 2014

Try a harder brush. You also can make a brush stiffer by shortening hairs. This also removes the fine points.
Do not brush over the screen, but dip onto the screen.

Chan Tran · Sep 2, 2014

zanxion72 said:
Try removing the focusing screen and submerse it in lukewarm water with plenty of dish washing liquid. leave it there for 10 minutes and then take it out, rinse it and that's it. Do not rub it or you may damage the Fresnel surface.

I must warn about this technique. The F3 screen (like the F, F2, F4 and F5 screens) are 2 pieces of glass sandwiched together and mounted in a frame. Submerge in water and the water can get in between the 2 pieces of glass and you can not get it out. I have done that.

bdial · Sep 2, 2014

You can separate the two sections by undoing the 4 screws on the side.
The plastic is fairly soft though, doing nothing is probably better if you can ignore it.

Kyle M. · Sep 2, 2014

I go over them with a sticky note (post-it) then give them a blast of compressed air. Anything that remains after that I just have to ignore. Unfortunately I am very OCD and find this difficult today. I too once ruined the screen in an F3 by submersing it in soapy water, I had thankfully learned my lesson before I got my F2 and F. My F was absolutely horrendous when I got it, it is now nearly spotless.

shutterfinger · Sep 3, 2014

If you can rub an over ripe grape with your fingertips and not move/break the skin then you can use your fingertips to rub the focus screen in running water with a little dish soap on it. You might get microfine scratches that may or may not be noticeable.

Poisson Du Jour · Sep 3, 2014

Common lens microfibre cloth moistened with water, then gone over with a dry section of the same cloth.
Immersing the F3 focusing screen under a tap is ludicrous with a very real potential for mould/fungi to develop from just a tiny bit of trapped moisture.

Newt_on_Swings · Sep 3, 2014

Yea don't soak the screen, there's some tape that also holds the two piece screen together as well when you take them out of the black plastic holder.

camtec · Sep 3, 2014

I use plain household ammonia and have done for for many years and thouands of cameras. This will clean the smuges left by deteriorated foam. To clean the other spects I use a soft brush. Rule: On most cameras if the specs are sharp they are on the top of the focus screen. If they are blurry, they are on the bottom of the screen.

AgX · Sep 4, 2014

Foam residues can be got rid of with Ammonia? Interesting, so far I have only used organic solvents.

baachitraka · Sep 4, 2014

Do not clean it.

F4user · Sep 4, 2014

AgX said:
Foam residues can be got rid of with Ammonia? Interesting, so far I have only used organic solvents.

If you want to make plastic glue from focus screen ......

Newt_on_Swings · Sep 4, 2014

Ah I saw a video the other day of a technique to clean vinyl records by coating the entire surface with wood glue, then peeling it off when it has dried. Supposedly it gets everything out of the grooves to produce a cleaner sound. Maybe it might work just as well on the ridges of the focusing screens. Haha

Rick A · Sep 4, 2014

I lick mine, then leave the saliva to dry.

benjiboy · Sep 4, 2014

Rick A said:
I lick mine, then leave the saliva to dry.

But what about the focusing screen ?

OldBodyOldSoul · Sep 4, 2014

Meh, I just replace the screen, I'll clean all three of them in 60 years when they are all dirty.

Rick A · Sep 4, 2014

benjiboy said:
But what about the focusing screen ?

:crazy:

AgX · Sep 4, 2014

Newt_on_Swings said:
Ah I saw a video the other day of a technique to clean vinyl records by coating the entire surface with wood glue, then peeling it off when it has dried. Supposedly it gets everything out of the grooves to produce a cleaner sound. Maybe it might work just as well on the ridges of the focusing screens. Haha

There IS actually a commercial lens cleaning product that works just this way.

benjiboy · Sep 5, 2014

I never touch mine with any kind of brush, I blow them with canned air from an aerosol and clean the top with Eclipse lense cleaner, I understand you should never touch or try to clean the plastic fresnel lens.

Old-N-Feeble · Sep 5, 2014

WARNING: That high-pressure water can CUT your skin so be cautious!!

I've taken a filthy Fresnel, separated from the GG, to a car wash and used the engine degreaser to spray away most of the gunk. Then used the rinse at about 18 inches (give or take) to blast away nearly all the rest of it. Remember to hold on tight so the spray doesn't knock the delicate plastic Fresnel to the gritty concrete floor. I followed with a rinse with distilled water and a blast of Dust-Off both of which I'd taken with me. This worked better than anything else I'd tried.

Xmas · Sep 5, 2014

AgX said:
Foam residues can be got rid of with Ammonia? Interesting, so far I have only used organic solvents.

It is a lot simpler removing the screen and replacing the foam before it degenerates.

Cleaning the focusing screen

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