Date: 9/8/20 9:29 am From: Nagi Aboulenein <nagi.aboulenein...> Subject: [obol] Re: Another optics related question
Yes, lens coating can be very sensitive to careless cleaning and once gone or scratched, the coating can’t be restored. Years, ago, after destroying the anti-glare coating on some of my eyeglasses by cleaning them too vigorously with whatever piece of cloth was nearest, I’ve learned my lesson and am now more careful.
My guess for “microcloth” would be microfiber cloth. Either the little eyeglass cleaning cloths (generally a very fine weave) or the coarser weave (but still very soft) larger microfiber cloths would qualify, I would think. The common aspect of all of them is that they are very soft and not scratchy. When using the larger clothes with the coarser weave I would recommend at least shaking them for a few seconds to make sure that any dust/sand/debris particles are gone. Cotton cloths (e.g., t-shirts) can have some hard fibers in them, but in a pinch, will do if used gently.
In theory the best approach is to use a lens-cleaning brush (compact, fits in a pocket like a pen) or blower to first get any sand/dust particles off the lens (see attached photo of blower), then use a lens cleaning cloth as above to gently wipe off. This is for dry cleaning of the lens. For other situations (e.g., salt water spray when at the beach, etc,) I wipe the lens with one or two alcohol-soaked lens cleaning wipe (e.g., Walmart carries excellent Zeiss lens-cleaning wipes at their optics departments).
Tissues, paper towels, TP all have little, often invisible, pieces of hard wood debris in them that don’t hurt our noses (or other parts), but that definitely are going to hurt your lens coatings.
On Sep 8, 2020, 08:48 -0700, larspernorgren <larspernorgren...>, wrote:
> Just what is a "microcloth"? Should I make an effort to use them over t-shirts, toilet paper, paper towels? In high school our physics teacher explained how the coatings on lenses worked, and how easily these delicate layers could be damaged by careless wiping. Everytime l get a new set of prescription glasses they come with a case and cleaning cloth. Every time l lose those glasses l keep the case and cloth. I have also acquired small pieces of textile targeted for lens care at symposia, complete with the event's logo.
> The various cloths in my possession are highly variable. Some are hard and smooth and make me think they might scratch the coating directly, or fail to absorb dust particles and blemish the coating by a sort of secondary action. Some of these cloths are very thick, pleasing to my fingertips. I fantasize such absorb the dust and lovingly cleanse the sullied lense. Even the best of textiles must eventually get clogged. Can they be cleaned, and how?
> Is it advisable to store clean cloths in a ziploc bag or other tightly sealed device? I always keep eye glasses in the glove box, and accompanying cloths in the glasses' case I got at time of purchase. Typically, after a drive from Fields to Roaring Springs my glove box has dust in it. So does the inside of most of the eyeglass cases. Isn't it probably worse to use a "micrcloth" drenched in road dust than an immaculate, disposable paper tissue? Will vigorous shaking render the dusty cloth safe? How about using drinking water for a field cleaning?
> Sent from my Verizon, Samsung Galaxy smartphone