Image of the day

Captured by
Gary Taylor

M27 - Dumbell Nebula

My Account

New to Astromart?

Register an account...

Need Help?

cleaning lenses

Started by cysmarc, 12/03/2008 12:13AM
Posted 12/03/2008 12:13AM Opening Post
Hi,
First things first! I am not cleaning my lens (When needed I'll send it to Dr. Sherrod) Well here goes.
Can lens tissue really do any scratching (after one blew off whatever could be blown off)?
Also, it seems from many posts, that people are afraid they [COLOR="Navy"]MAY[/COLOR] have caused damage, then whatever scratches were caused would only be visible at certain angles and in bright light otherwise it would not be a [COLOR="Maroon"]"may have caused damage"[/COLOR] but there would be no doubt about having done damage. Being the case can micro scratches that are so tiny as to not be visible readily be any worse than some dust on the lens?
I hope I make sense. I still am scared stiff of cleaning my lens but maybe I shouldn't be!

Posted 12/03/2008 01:21AM #1
If you use GOOD lens tissues http://www.optoalignment.com/opto_wipes.html , not the ones you buy at Wal-Mart, but ones made for real lens cleaning, then if the grit is removed first the tissue should not scratch the coatings.
The real problem is, was all the dust removed and how much pressure was applied on the first wipe.
I have not scratched a lens yet with these tissues.

[SIZE="Large"][/SIZE][COLOR="Blue"][/COLOR] Floyd Blue grin
Amateur Imager
Posted 12/03/2008 11:05PM #2
Yes, there can still be grit "glued" to the lens after blowing
it off. If the lens can be safely removed from the cell, you can
try to rinse it off with a spray bottle. Another approach is to
do a couple iterations only dabbing or blotting the lens with cleaning
solution (no wiping) to loosen and remove any grit. And use
"wiping" only for later iterations where the lens is relatively clean.

I often find that there are many more scratches visible after
cleaning, but I feel this is a "visibility" issue for the
scratches, rather than damage from cleaning. If you shine a
bright lamp at the lens before cleaning, there is bright crud
everywhere with many features, etc. Afterwards the lens is
pristine, but if you look hard and hold the lamp just right,
you can often see faint sleeks and lines that were not
visible before. It is interesting to use a bright lamp on
a brand new factory fresh lens (from high-end makers, etc.)
and note the faint sleeks and scratches left over from factory
polishing. These will have no impact on images, but may
be alarming if you first notice them after cleaning the lens.

Over-cleaning (cleaning too often, etc.) has obvious problems.
But you can also get bad stuff on the lens (chemically
reactive particles, acids from finger prints, etc.) that will
do damage if left on there too long. So there is some trade-off.