Reader's Comments - Index of - Free

Cleaning Cameras
the lens is cleaned is important. Perhaps you did make those circle scratches on your lens.
But maybe they're not too deep. Do they scatter light and decrease the contrast on your
negative? Sure. A lot? Probably not too much. But if you clean your lens once a week (or
day?) and continue adding these scratches, it will become real noticeable in a hurry.
For cleaning an optical surface, straight wipes are much better. And for those of you who
are really paranoid, you should switch to a different part of the cloth for *each* wipe. That
way, if you did pick up a bit of sand, you won't drag it across again on the next wipe.
Dusting off lenses before using a cloth is important because it (hopefully) removes any
abrasive materials.
I would also definitely steer clear of using any cloth that isn't sold as a product specifically
for cleaning optics. T-shirts may be nice and soft to the touch, but how sure are you that a
spec of sand (or thousands?) isn't stuck in that shirt from the last time you went to the
beach or worked in the yard (or there when you bought it)? Sure enough to risk scratching
your $2000 300 mm Nikkor? It really isn't worth it. Paper towels, tissue paper, cotton
swabs... I have seen all of these readily scratch glass. But these are not manufactured or
packaged to ensure that they do not contain *any* abrasive materials. If you know anyone
who has regularly cleaned their eyeglasses with tissues or paper towels for a long time, take
a look at their eyeglasses with a really bright flashlight and you'll see what might happen to
your lens.
Why am I going on so much about sand? Because the damage is permanent. Once a scratch
is there, it's not coming off.
As far as cleaning solutions go... Again, I'd stick with ones that are supposed to be for
optics. I am not sure what type of AR coatings are put on camera lenses, but many are quite
durable and resistant to many solvents (we use isopropanol, methanol, acetone, toluene,
sometimes even dish washing detergent). Since camera lenses are consumer products, I
would expect the coatings to be pretty durable. But again, it comes down to quality...
Rubbing alcohol has isopropanol in it but only a few percent. The rest is water, detergent
and who knows what. I don't expect that the stuff sold as "pure" isopropanol is as good as
the stuff I would use at work (reagent-grade, contaminants are measured in parts per
million!) but it's far better than rubbing alcohol (and cheaper than reagent-grade too:). That
goes for "exhaled water vapor" too... Do you know what's in it? Well I don't either, and I
wouldn't risk putting it on my lens. Biological materials tend to be difficult to clean and
corrosive if left on coatings for long periods (fingerprints can permanently damage a
coating if left long enough).
And here's a tip: If you've just put some cleaning fluid on your cloth and tried wiping off a
fingerprint, and there's still some there, wet another spot of the cloth (or a new cloth) and
wipe again. Don't continue to reuse the cloth that isn't working. The solvent can only take
http://www.photo.net/learn/cleaning-cameras (18 of 19) [5/15/2002 7:15:53 PM]