[vladimiroltean]

Hi, I have found contradictory advice on the net regarding this subject, so I will try to explain my situation clearly. I have an MX which has a viewfinder not overly dirty, but nevertheless I would like it to be spotless (it's not scratched yet, just has some black marks here and there). I'm planning to clean it myself using the following procedure, and I'd love to hear opinions about it before doing any silly thing again:
- with a pair of gloves and tweezers, take the screen out and put it on a clean dish.
- take a blower and get the dirt off it, also blow in the MX pentaprism which might be as well dirty
- either immerse the screen in lighter fluid, or clean it with lighter fluid on a cotton bud (which one is better? will I ruin the screen?)
- at the end, remove any cotton lint with the brush end of a lenspen.
On a side note, where can I find shims for the Pentax MX? With the SMC-M 28mm, it's not showing exactly infinity when it should, so I think it's slightly front-focusing.

[Spodeworld]

I've heard that the focusing screen is so delicate that even a cotton bud could harm it. Don't know what to say about lighter fluid.

[TomB_tx]

Lighter fluid is likely to ruin the plastic screen. The plastic is also very soft (to mold the fine detail in the surface) so is easily marred by rubbing with anything. I'd try distilled water with a few drops of windex, immersing the screen to free any bits of foam (the usual stick stuff that gets on them), maybe use an ear syringe to squirt the solution against it, rinse with pure distilled water, blow it off with a rocket blower (while holding by the edges - it is so light it can be blown about if not held).

[KansasPen]

I tried cleaning my K10D focusing screen when I was showing a lot of dust through the view finder. I had great success with blowing out the housing. However where it went downhill was wiping off the focusing screen. I used a microfiber cleaning cloth and nikon lens cleaning solution. It was never the same. Once placed back in the camera it was noticeably darker and there were fine scratches on it. I ended up buying a new screen to correct the problem. When they say not to touch the screen they mean it. I recommend just using an air blower.

[vladimiroltean]

Well have you personally ruined any focusing screen by touching it? Because I know of people who cut ME Super screens down to size for their DSLRs, and that kind of behaviour would most likely harm them more than a cotton swab. But I have a little fear too, so that's the reason why I'm asking.

I tried cleaning my K10D focusing screen when I was showing a lot of dust through the view finder. I had great success with blowing out the housing. However where it went downhill was wiping off the focusing screen. I used a microfiber cleaning cloth and nikon lens cleaning solution. It was never the same. Once placed back in the camera it was noticeably darker and there were fine scratches on it. I ended up buying a new screen to correct the problem. When they say not to touch the screen they mean it. I recommend just using an air blower.

Sorry, didn't see your post. Are you sure the darkening wasn't because of the solution used? I don't know, I might just wipe it with a brush then.

[KansasPen]

Well have you personally ruined any focusing screen by touching it? Because I know of people who cut ME Super screens down to size for their DSLRs, and that kind of behaviour would most likely harm them more than a cotton swab. But I have a little fear too, so that's the reason why I'm asking.


Sorry, didn't see your post. Are you sure the darkening wasn't because of the solution used? I don't know, I might just wipe it with a brush then.

Yes I ruined it with a microfiber cloth. Safe for LCD tvs, lenses and the like. Ruined my focusing screen. Probably less abrasive then a cotton swab and lint free even a microfiber cloth wouldn't do it.

[KansasPen]

I wouldn't think the solution would be the culprit since it's designed for camera lenses specifically. The focusing screen is just so delicate as previously stated by another poster.

[Philoslothical]

I've been thinking about this, as I'm going to be experimenting with a couple different screens soon. With the disclaimer that I haven't done this yet and don't take any responsibility if you do, I think a safe way to do it would be to put the screen in a small plastic bottle of distilled water and gently shake the whole bottle. Theoretically, only the edges of the screen will come into contact with the bottle, but the friction of the distilled water should help significantly to clean it. Distilled water on its own is quite a good solvent, and would definitely be safe for plastics like this.

[GibbyTheMole]

I haven't personally done it, but from what I've read some use distilled water and a tiny bit of dishwashing liquid, followed by a couple of distilled water rinses, followed by a hair dryer (being careful you don't blow the screen away in the process) to dry the thing. This seems like a pretty safe method to me.

[Spodeworld]

I've heard about the dishwashing soap and distilled water route, but as noted, use a dryer afterward. A Giotto blow dryer would work. You want to use a drying aid instead of just letting it air dry as that alone might leave streaks. And, you don't want to apply any fibers to wipe it off, as they may scratch the surface.

[vladimiroltean]

Nice, I might give it a try as soon as someone reports success with this method

[altopiet]

I've learned to live with a “not perfectly clean” screen, as I live in a place where I'll most probably have to clean the screen every week, because of all the dust. If you really have to, I would suggest reading this link Focus Screen and Lens Cleaning Tips, Any Comments - Photo.net Pentax Forum. If I do decide to clean mine, I would do it as explained in the link

[stevebrot]

I've learned to live with a “not perfectly clean” screen, as I live in a place where I'll most probably have to clean the screen every week, because of all the dust. If really have to, I would suggest reading this link Focus Screen and Lens Cleaning Tips, Any Comments - Photo.net Pentax Forum. If I do decide to clean mine, I would do it as explained in the link

Excellent link! Thanks for sharing. The article does a good job of explaining the hazards and gives what appear to be two good solutions as well.


Steve

[Tom in Delaware]

The link to the Photonet post on screen cleaning has some good stuff. My experience with trying to clean a focusing screen was that the fresnel surface is very delicate. For lenses, however, I just huff on them and clean with a clean microfiber cloth, never scratched one yet.

[frank]

I've cleaned many focusing screens: both film and digital SLR cameras, never had any problem yet. I always use a strong blower (a big size Giotto Rocket-Air) plus Eclipse fluid and PEC pads combo. The screens I've cleaned so far:
LX/MX/SuperProgram/Z1p/MZ-3/MZ-S, Ds/K10D/K20D/K7/K5...







These work great on cleaning lenses too. Yes, the Eclips and PEC pads aren't cheap, but well worth the cost imo.