From: bbarton@Ingres.COM (Brian Barton)
Subject: Re: lens protection
Summary: 
News-Software: VAX/VMS VNEWS 1.4-b1  
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Organization: ASK Computer Systems, Ingres Product Division
Date: 31 Jul 92 19:51:28 GMT

In article <3484@eastman.UUCP>, barnick@mesa.Kodak.COM (Wil writes...
>In article <1992Jul29.205328.22023@news2.cis.umn.edu> weiss@epx.cis.umn.edu writes:
>>A professional photographer has suggested that I NOT place a skylight filter
>>onto my new APO 100-300mm f4 zoom.
>>He contends that doing so will degrade the lens performance and that the
>>coating already on the lens should be sufficiently resistant to damage.
>>Anyone have experience with this issue?
>>Thanks!
>> 
> 
>You need to drop the lens just once and you'll know what's wrong with the
>above statement.  Also, unless you are shooting in a vacuum the air
>quality will play a bigger part in "degrading" the image than a *good*
>skylight or UV filter.  I am not trying to be funny here.  Air is not
>that clean and temperature changes in air currents change the appearance
>of an image greatly,  so the filter imperfections becomes insignificant.
>A good example of this use to be shown in the Corning Museum.  They had
>a piece of optical glass about 10 feet long and a tube of air of the
>same length.  The image is much clearer through optical glass with just
>10 feet of air.  That is why we use fiber-optics for communication rather
>than just shooting a laser through air (among other reasons).
> 
>Also, the coating on the lens is there for many reasons,  but I do not think
>"resistant to damage" is one of them.  Am I wrong ???  You scratch the coating
>and its all over.
> 
>I would suggest you get a few more opinions.
> 
>PS: Just my opinion.
> 
>WMB

With all due respect to Bill, I definitely recommend _not_ using _any_ filters
on your lenses.  Let's say you buy a Nikkor 180 2.8 ED lens.  An extremely
sharp and _expensive_ lens.  Why would you want to degrade the image 
quality of your pictures to _protect_ your lens?

What exactly do you do with your lenses that would require protection.
Do you shoot in jungles or thorny bushes on a regular basis.  Even
a ding in your lens will _not_ cause any degradation in picture quality. 

I've owned lots of Nikkors over the years and I never use filters or lens
caps.  Why not get a lens hood?  That will _protect_ it from whatever it
is that you're trying to protect it from.

After all of these years, the only thing that ever happened to one of my
Nikkors happened when I feel down a mud embankment.  I fell and scratched
the front element of my lens really badly.  To replace the front element
cost about $75.  To fix my damaged F3 cost over $100 and to fix my
scratched arm took about 45 minutes.

After spending all of the money on the lens don't cover it up with
something else. It just doesn't make any sense.

Brian

> 
> 
>--
>***  William M Barnick ** Eastman Kodak ** barnick@Kodak.COM ******************
>***  Electronic Imaging Platform Center * Color Scanning Systems Lab          *
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