strangerbeat
Member
My Bronica ETRS has a lot of dust and gunk from the foams stuck in some of the crevices... its really annoying.
How can I properly remedy this situation? Air cans and pumps arent cutting it... i really need to get in there and rub.
Any proper care suggestions? :bang:
How can I properly remedy this situation? Air cans and pumps arent cutting it... i really need to get in there and rub.
Any proper care suggestions? :bang:
pvdhaar
Peter
Whatever you do, don't rub the screen. The Fresnel pattern in the synthetic material is very prone to scratching. For the SQB, I used to take out the screen and dip it in lukewarm water with detergent in it. Rinsed it with clean water afterwards.
But even if it's not spotless, anything that's left behind doesn't show on the pictures
But even if it's not spotless, anything that's left behind doesn't show on the pictures
Bill58
Native Texan
You can use a slightly soapy solution of water and liquid dish detergent w/ a soft brush to clean, then rinse thoroughly in distilled water and let dry. Distilled water leaves no spots or rings after drying.
FallisPhoto
Veteran
Whatever you do DON'T USE ALCOHOL!!! Alcohol will turn your focusing screen opaque and white. Rubbing the screen is also ill-advised, since if you rub it, the gunk doesn't come off, but lodges in the crevices. That said, if you have GOT to do it, use a very soft artist's brush and use naptha to dissolve the foam gunk, NOT alcohol. Don't rub hard; let the solvent do the work. Plan on it taking a l-o-o-o-o-n-g time (several days). This should only be done on screens that are bad enough that you have little to lose, because even with all the precautions, it still probably isn't going to come out well for you.
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strangerbeat
Member
wow. best advice i've seen after googling a bunch of other threads the past few days. thanks guys!
sreed2006
Well-known
I had a dirty focusing screen once, and put it into a solution of rubbing alcohol and water.
That ruined it immediately.
Now, if there's a speck on the focusing screen that won't come off with a blast of air or a light stroke with a super-soft brush, I just admire it when I'm composing pictures and think back on the day I destroyed that focusing screen.
That ruined it immediately.
Now, if there's a speck on the focusing screen that won't come off with a blast of air or a light stroke with a super-soft brush, I just admire it when I'm composing pictures and think back on the day I destroyed that focusing screen.
FallisPhoto
Veteran
It'll do that -- probably in mere seconds too.
I once found a post somewhere or other online where a supposed repair guy was actually recommending alcohol for cleaning focusing screens; if it wasn't ignorance the guy has a really nasty sense of humor.
I get TLRs for repair sometimes with alcohol smears on their focusing screens. If it's on the smooth side, it can sometimes (less than half the time -- and only if it isn't too bad) be polished out with NevrDull metal polish and a lot of patience; if it is on the other side, it's just plain ruined. On SLRs, of course, the alcohol smears are always on the ridged side -- so they're just toast.
Mohan
Established
Well, It's ok on Groundglass focusing screens.
FallisPhoto
Veteran
Depends on the type of alcohol. Rubbing alcohol is never okay to use, because (1) it is only 90% pure, at best, and only god and the company that makes it knows for sure what the other 10% is. For example, I read the lable on one bottle recently that contained balsams, oils, and other things sensible people don't want in their cameras -- the idea being to get the crud out of the camera, not to put more in, and (2) isopropyl alcohol is a much more aggressive solvent than other types of alcohol and can dissolve and otherwise attack things you don't want it to -- and the fumes can do this, not just the liquid itself. Ethyl alcohol, on the other hand, is relatively benign; I still wouldn't use it on a focusing screen though, even ground glass, when there are other, more harmless, solvents that work just as well, with far less risk to the camera. It won't hurt the ground glass itself, but it will attack nearby balsam cements, for example. I'm convinced this is why you see so many old Voigtlander plate cameras with Skopars that have seperating lens elements.
Denatured alcohol and ethyl alcohol are the only alcohols I use in cameras and then only in very small amounts under tightly controlled specific conditions -- none of which involve focusing screens. Truth be told though, if a focusing screen in an SLR gets something stuck to it, you're almost certainly going to be a whole lot better off learning to live with it than you are going to be if you attempt to clean it -- especially if it is a fresnel lens.
Murray Kelly
Well-known
sevo
Fokutorendaburando
That, yes. But unless we're talking very old sheet film cameras with original glass, you cannot assume that you have a ground glass made entirely and exclusively from ground glass. Almost every ground glass with fresnel screen, microprism, split prism or equivalent optical element has at the very least a sandwiched plastics layer - the acrylic age started right after WWII!