lens caps ?

(jjs) wrote in message ...
In article ,
(Ken Smith) wrote:

(jjs) wrote in message
...
In article ,
Bob Salomon wrote:

Yes, the most authoritive kind. I had a set of Rollei Bay VI filters -
including 2 Softars in a Coast Filter Wallet. This item gave off
plasticisers which migrated to all of the filters in the wallet (9). All
of the filters had to be thrown away. The owner of Coast would not
accept any resposibility for putting out such an item in the photo
market.

What a nightmare! Thanks for the good warning.


Oh sure, another thing to worry over based on "it happened to me"
as an substitute for an actual scientific analysis of one plastics
migration potential vs. another. [...]

You might have missed Salomon's subsequent qualifying statement. He
pointed out that it was one particular brand (Coast), and not a sweeping
generality.

His point was plastic migration, his experience was the Coast
product, and he directed this experience to my use of a
commercial grade plastic from a food product as a lens cap.
If it's true I am greatly indebted. Off it goes. But what do
we really have to go on here? Perhaps the filter case had been
in some heat, and the plastic adhered to the filters. Damage
would surely result, if left there long enough. Does that
compare with my lens cap that does not make contact? If there
is however a gaseous migration, great, lets get some chemical
engineer in on this. I'd be fascinated to know. Otherwise it's
just another chicken little. Another insentive to buy yet another
product, instead of improvising.

"Ken Smith" wrote

If there is however a gaseous migration,
great, lets get some chemical engineer in on this.

Vinyl plasticizers do evaporate and then re-deposit.

Examples are the fogging of the inside of car windows
when the vinyl upholstery sits in the sun and the
'gooing' of Xerox/laser printing when stored in vinyl
folders.

Unless the lenses have an organic coating, or come from
a Diana, the fog will dissolve and come off with ammoniated
window cleaner. No permanent damage is done to the glass.

Plasticizers and other organics are the normal cause
of fog on lens surfaces. Cleaning it off seems to do
no harm.

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.

In article k.net,
"Nicholas O. Lindan" wrote:

Unless the lenses have an organic coating, or come from
a Diana, the fog will dissolve and come off with ammoniated
window cleaner. No permanent damage is done to the glass.

that isn't the case with Softars which, like many other types of
filters, are acrylic and not glass. Nothing would remove the coating
without ruining the Softar.

--
To reply no_ HPMarketing Corp.