Is it possible to remove the coating on a lens?

"Bandicoot" wrote in message
.. .
"William Graham" wrote in message
news:_u45d.104785$MQ5.12373@attbi_s52...

"Eldritch" wrote in message
...
Bandicoot wrote:


Glass is very resistant to acids (except Hydroflouric and, to a
lesser
extent, Phosphoric if hot) but has less resistance to strong
alkalis.
That
would make me a bit nervous of using a strong caustic like drain
cleaner -
not saying it wouldn't work, I don't really know, but the idea would
make me
a bit cautious...


Peter



Interesting. I thought glass was impervious to everything. Live and
learn. I'm already cautious about working with Draino. Lens are
made
of more materials than just glass. I don't want to risk splashing in
onto any surrounding materials which would dissolve.



Molds will attack glass.....Try leaving a drinking glass buried in your
back
yard for a couple of years.....

The irridescence in glass often caused by burial is due to it flaking into
very thin layers, due to the action of alkalis in the soil.

I was referring to a white, "milky" stuff that is impossible to clean
off.....I was informed that it was the result of mold action on the
glass.....There are very few things that are really not biodegradable, given
enough time....

"Bandicoot" wrote in message
.. .
"William Graham" wrote in message
news:_u45d.104785$MQ5.12373@attbi_s52...

"Eldritch" wrote in message
...
Bandicoot wrote:


Glass is very resistant to acids (except Hydroflouric and, to a
lesser
extent, Phosphoric if hot) but has less resistance to strong
alkalis.
That
would make me a bit nervous of using a strong caustic like drain
cleaner -
not saying it wouldn't work, I don't really know, but the idea would
make me
a bit cautious...


Peter



Interesting. I thought glass was impervious to everything. Live and
learn. I'm already cautious about working with Draino. Lens are
made
of more materials than just glass. I don't want to risk splashing in
onto any surrounding materials which would dissolve.



Molds will attack glass.....Try leaving a drinking glass buried in your
back
yard for a couple of years.....

The irridescence in glass often caused by burial is due to it flaking into
very thin layers, due to the action of alkalis in the soil.

I was referring to a white, "milky" stuff that is impossible to clean
off.....I was informed that it was the result of mold action on the
glass.....There are very few things that are really not biodegradable, given
enough time....

Eldritch wrote in message ...
I just received a camera I purchased through eBay from a fellow in
Ukraine for about $43.00. It's a Russian FED-3a. The camera arrived
in apparent good condition. It's pretty clean and works fine
mechanically. But after putting my first roll of film through it, I
found a problem with the lens. Blurry, overly contrasty pictures.


So I cleaned the lens again and then took a closer look at it through a
magnifying loop. The front surface of the lens does not look
scratched, but the coating looks pretty badly scratched up. There are
hundreds of little scratches through the coating. I first thought
fungus might have done than, but perhaps it's just from improper lens
cleaning. The scrapings through the coating is all toward the center
of the lens. There's a narrow ring around the outside of it which is
clear and apparently spared from these scrapings.


I can probably buy a replacement lens for $40 or so, but I'm wondering
if there's any way to salvage this lens without incurring great expense.
I've been told that the Industar-61 lens is a good one.


I wouldn't attempt to re-coat the lens, but is there a way of removing
the remaining coating without doing other damage?


E

It is possible and easy (as I experienced by my mistake) with fluid
for cleaning the heads of the tape recorder.
The coatings are tiny vapour layers of metalls on the glass surface.
Mentioned fluid removes metall particles from the taperecorder heads.
Try it first on an old multicoated filter.

Eldritch wrote in message ...
I just received a camera I purchased through eBay from a fellow in
Ukraine for about $43.00. It's a Russian FED-3a. The camera arrived
in apparent good condition. It's pretty clean and works fine
mechanically. But after putting my first roll of film through it, I
found a problem with the lens. Blurry, overly contrasty pictures.


So I cleaned the lens again and then took a closer look at it through a
magnifying loop. The front surface of the lens does not look
scratched, but the coating looks pretty badly scratched up. There are
hundreds of little scratches through the coating. I first thought
fungus might have done than, but perhaps it's just from improper lens
cleaning. The scrapings through the coating is all toward the center
of the lens. There's a narrow ring around the outside of it which is
clear and apparently spared from these scrapings.


I can probably buy a replacement lens for $40 or so, but I'm wondering
if there's any way to salvage this lens without incurring great expense.
I've been told that the Industar-61 lens is a good one.


I wouldn't attempt to re-coat the lens, but is there a way of removing
the remaining coating without doing other damage?


E

It is possible and easy (as I experienced by my mistake) with fluid
for cleaning the heads of the tape recorder.
The coatings are tiny vapour layers of metalls on the glass surface.
Mentioned fluid removes metall particles from the taperecorder heads.
Try it first on an old multicoated filter.

Eldritch wrote in message ...
I just received a camera I purchased through eBay from a fellow in
Ukraine for about $43.00. It's a Russian FED-3a. The camera arrived
in apparent good condition. It's pretty clean and works fine
mechanically. But after putting my first roll of film through it, I
found a problem with the lens. Blurry, overly contrasty pictures.


So I cleaned the lens again and then took a closer look at it through a
magnifying loop. The front surface of the lens does not look
scratched, but the coating looks pretty badly scratched up. There are
hundreds of little scratches through the coating. I first thought
fungus might have done than, but perhaps it's just from improper lens
cleaning. The scrapings through the coating is all toward the center
of the lens. There's a narrow ring around the outside of it which is
clear and apparently spared from these scrapings.


I can probably buy a replacement lens for $40 or so, but I'm wondering
if there's any way to salvage this lens without incurring great expense.
I've been told that the Industar-61 lens is a good one.


I wouldn't attempt to re-coat the lens, but is there a way of removing
the remaining coating without doing other damage?


E

It is possible and easy (as I experienced by my mistake) with fluid
for cleaning the heads of the tape recorder.
The coatings are tiny vapour layers of metalls on the glass surface.
Mentioned fluid removes metall particles from the taperecorder heads.
Try it first on an old multicoated filter.

Bob Monaghan wrote:
scratches on the lens would reduce contrast, not increase contrast.
The scratches would reflect light into the dark scene elements on
the negative, reducing contrast ratios and overall contrast of scene.


I'm really sorry I mentioned contrast. It seems to have distracted
from my question about removing the damaged coating on the lens. As
others have already suggested, perhaps I'm using the word incorrectly.
I'm seeing something in the photographs, but perhaps "contrast" is the
wrong word.


I've uploaded two photographs to pbase.com. The photographs are hazy,
which I attribute to the partially abraded coating. These scans don't
fully represent the haziness/blurriness which can be seen in the
original photos. These images appear considerably sharper than the
originals.


http://www.pbase.com/eddalex/inbox

Note that glare reflections on the auto's bumpers is much larger than
it should be. It's large and completely burns out. THis is what I
meant when I mistakenly used the word contrasty. You can tell me what
it's properly called.


If there are any suggestions on dealing with the problem of the damaged
coating, I'm still open to suggestions.


E

Matt McGrattan wrote:

The advice to get a replacement lens is good.




You're probably right. I just thought it wouldn't hurt to ask the
question.


There are a lot of things that are hard to clean if you don't know
which cleanser to use, and very easy if you do. There are a lot of easy
tricks and secrets in the world that i don't know. I thought there
might be some easy-to-use chemical I could apply to remove the coating.
It would seem that the answer to my question is, no. But I didn't
know that before I asked the question.


E

Matt McGrattan wrote:

The advice to get a replacement lens is good.




You're probably right. I just thought it wouldn't hurt to ask the
question.


There are a lot of things that are hard to clean if you don't know
which cleanser to use, and very easy if you do. There are a lot of easy
tricks and secrets in the world that i don't know. I thought there
might be some easy-to-use chemical I could apply to remove the coating.
It would seem that the answer to my question is, no. But I didn't
know that before I asked the question.


E

Eldritch wrote in news:2rp7qlF1ckqmuU1@uni-
berlin.de:

http://www.pbase.com/eddalex/inbox

Cool soft focus effect. Congratulations!