Cleaning focussing screen of Leicaflex SL

[tony_salce]

The focussing screen of my SL has some dust and/or fine particles on

it that are most annoying. Or at least I think they're on the

focussing screen. Maybe they're on the mirror ? I really don't know

How do I best remove them whether they be on the focussing screen or

on the mirror ?

 

Regards,

 

Tony Salce

[sal dimarco]

Using a very fime camel's hair brush wipe the surface of the mirror and the screen above it. If the dust is still there, sendthe camera in for a cleaning, because the dust is inside.

[albert knapp md]

Tony:

If the camel brush gambit fails, try compressed air in short

spurts and NOT too close to the camera or the optics as it may

result in condensation. If this fails, send it back to Leica USA,

DAG or another competent repair service of your choice.

[jay_.]

Be very careful using a "camel's hair brush" on the mirror. If the bristles have been touched by human hands, they will have oil on them and smudge the mirror. If there are any particles in the brush or on the mirror, they can scratch it permanenly with ease: Leicaflex mirrors are *very* fragile. Some repair books recommend dipping the camel's hair brush in ether and shaking it dry first--but I don't endorse handling either for a couple of reasons (it's highly flammable and you don't want to inhale the vapor!). I also don't endorse using canned air to clean out the mirror box because if held at the wrong angle you can squirt aerosol propellant into it. I use one of those really large blower bulbs. If that doesn't get the specks off, you can take a rolled-up piece of lens tissue (not the impregnated kind used for eyeglasses!)and tear the end off (to make it ragged)and use it to just loosen the individual specks (i.e. don't actually wipe with it)so the blower bulb will remove them. I suggest holding the camera with the lens opening facing down when doing this, sothe particles drop out of the camera.

 

Note that with SL/SL2 finders there are sometimes small brownish blotches in the finder...that is a kind of fungus, and will not come off without a professional disassembly and cleaning (if at all).

[doug herr]

<I>Note that with SL/SL2 finders there are sometimes small

brownish blotches in the finder...that is a kind of fungus, and will

not come off without a professional disassembly and cleaning (if

at all).</I><P>

It could also be de-silvering, which is fixed by replacing the

prism. I usually ignore the dust on the viewscreen until the

camera has to go in for service for other reasons. It's too easy to

mess up a viewscreen or mirror.

[neil_parker]

In my experience, almost anything you do to clean a focusing screen (and even more so a mirror) is quite likely to make things worse. If you blow it with canned air, even gently, you will build a static charge that will turn the screen into a dust magnet in the future. A blower brush might take off large, loose chunks, so its ok for that use but not likely to help for much else, and using a brush is almost certain to put more crud on than it takes off, unless it is scrupuously clean, and has no loose hairs.

 

If you see sharp dust spots they are on the screen, not the mirror, and definitely never try to clean a mirror except as a last resort, as they are 'front surface' and will scratch immediately.

 

I think the best thing for a non-repair person to do is what I do; develop a mental photoshop 'dust & scratches' filter, I just don't notice it anymore:-)

[tony_salce]

Thank you all for responding to my query. Your replies have all been very instructive.

 

I know it is not deslivering of the main prism because Sherry put a new one in about a year ago. It is just dust.

 

I'll just leave it until it is next due for a service.

 

Thanks again for your replies.

 

Regards,

 

Tony Salce

[oliver_s.]

AFAICT the 'fungus' is the inner side and glue of the leatherette strip over the lens mount dissolving. At least mine does precisely that.<p>I cleaned my SL's mirror box by breathing into it, in the way you would to get a sound out of a clarinet. It worked well.<p>Dirty mirrors and focussing screens are annoying but cannot affect image quality for obvious reasons. Exception: the user, shocked by the amount of dust on the focussing screen, starts trembling.

[don_gillette]

The spots you see in the viewfinder, if sharply defined are on the ground glass. Take a camel hair brush that you have sprayed in ether and let dry, not all ethers will work some have contaminents, be careful. Then very gently remove any dust off the underside of the screen and the mirror. Do not use compressed air to clean , you could blow dust to the top of the ground glass which would require complete dissassembly to remove and then the prism would have to be re=aligned. When cleaning the mirror remember that it is a front surface silvering type, (very fragile coating. Always keep either a body cap or lense on the body to keep dust out..