I recently came across a clip on youtube which showed the process of making camera lenses. I noticed them using acetone as a lens cleaner. My question is how effective is acetone as lens cleaner? Will acetone damage the coating on the lens?
Here's Bob Atkin's answer on the topic and I generally agree. In a nutshell, don't use it unless you really know what you're doing and have it sourced. As a general rule of thumb, use lens cleaning supplies specifically made for lenses and don't get too paranoid about the front element being clean. Seriously, it takes quite a bit to really mess your image quality and it isn't necessary to be fastidious about it.
You'll note that at the point they did that, it was just a glass blank. What will the acetone do to the glass and coating? Pretty much nothing. What will it do to the rubber gaskets that seal the dust out of the lens? That's the real question to me. Having worked around fibre-glass for a few years, which uses acetone in pretty large quantities... well, I wouldn't be putting it into contact with anything rubberized that I cared about keeping the rubber in good shape... it just seems to dry it out way too fast and lead to cracks. Just not worth it to me, especially when we are talking about the outer surface of the front element.
Acetone is an excellent solvant for some plastics. I've tested it with styrofoam once here :)
It does clean pretty good though.
For my filters (polarizer etc.) I was most successful with liquid soap and water. Not everything works, but there are liquid soaps which do not leave any stains (and which I'm using for my glasses as well now :)). Also works for lenses, but then you should not pour water on them directly but use a wet towel.
Edit: Generally about alcoholes for cleaning. I tested them a little bit, Alcohol and Isopropyl alcohol, mixed with water.
- Isopropyl always smears. Iff you hold the cleaning towel with your hands. The reason is that it will solve grease from the fingers and evenly distribute it on the surface. The solution is to use something grease-free for holding the towel (or whatever it is).
- Alcohols alone dry too quickly and leave stains.
- Water alone does not solve greasy particles.
- The best way to clean with alcohol based liquids I've found so far is to use water with some drops of alcohol (one of the above); the alcohol will bind greasy particles, the water will prevent the liquid from evaporating too quickly, so the drops can be removed easily and without stains using a dry towel.
Avoid using acetone on lens assemblies. It is a solvent and it acts on the components destructively.
It is not possible to predict what specific parts will be affected.
Note that a glass lens (singlet) is not the same as a lens assembly made of and with many different materials both organic and inorganic.
The first things you'll notice is that the paint and varnish used for the finish and engraved/etched fillings will soften, swell, and possibly lift before being dissolved. The serial number and lens information such as aperture and distance marks will be removed for example.
This is not a good idea. Instead, use materials and processes suitable for the equipment.
Acetone is a killer solvent. It's basically identical in behavior (and at least formerly in formulation) to nail paint remover which will soften and dissolve dried paint layers. You don't want even the fumes to come anywhere close to your camera.
Rubbery surfaces supposed to have a friendly touch can bleed out stickiness after a decade or so. Alcohol and a cloth can be used for getting the surface dry enough that it will be good for another few years. Use acetone instead, and the rubber will come off, as will the paint and plastic below it. It's a sledge hammer for working with plastics, and you would use it for working on a lens just as comfortably as working with an actual sledge hammer.
There may be uses in controlled parts of the production on parts not yet assembled with other parts. It may even be used in the process for getting the plastic parts molded. But it doesn't belong anywhere near an assembled product.
I use a variety of liquids on cotton swabs: naphtha, isopropyl alcohol (99% or 91%), and Zeiss lens cleaning fluid. I also use breath moisture. If oil in the lens has migrated to the glass, I remove the affected element and soak it in a small dish of water with a couple of drops of dissolved dish soap.
Acetone is a rapid solvent for ABS plastic. Almost any black plastic on a photographic lens is ABS. I have never used acetone on glass because I think naphtha probably achieves the same result, and does it safely. It's a good solvent and I have never seen it cause harm to coatings or glass.
Most inside coatings are hardened, but some can be quite soft. I am still working on how to avoid scratching inside coatings.
To treat mold (aka fungus, but not actually fungus) I use hydrogen peroxide and ammonia, 1:1 and let it stay on the affected glass for about 20 to 30 minutes. The mold tends to disappear, but if you breathe moisture on the lens where the mold was, you can usually see a tracing of where it was. But the H2O2 + ammonia mixture is supposed to kill the mold and any spores.