Lens problem - fungus??

Chaps,

noticed something odd on the 135mm lens for my C330f. What appears to be a
pale whitish smear of dirt - however not on the outside or film side
surfaces of the lens, somewhere within the lens.

Is this the dreaded mould or cement deteriorating? Put the lens outside in
the sun until it rained. Now packed it in a platic bag with dessicant.
Anything else I can do? Is it catching?

Pete


--
http://www.petezilla.co.uk

krishnananda wrote:

Can you see if the deposit is between 2 lenses in a group or is on a
glass-air interface? If the first it is probably separation/cement
failure. If the second is can be fungus or another deposit. Fungus can
be abated with the lens-in-the-sun trick, but that doesn't always take
care of the problem.


Hard to say exactly where it is. Just blasted the lens with a UV lamp,
though as the UV lamp is probally intended for parties etc I'm not sure it
is short enough wavelength to do the trick. Can't do any harm though.

If it is separation you should probably consider replacing the entire
lens -- C330 lenses aren't that expensive. If it is some kind of deposit
a good camera repair shop should be able to clean it.


Suspect it is the latter - I've heard the fungus described as 'snowflakes'
etc, and it is nothing like that. I suppose the best bet is to just keep
using it unless I become unhappy with the images it produces. If it does
go too far I could try swapping the viewing and taking lenses, nothing to
loose at this point. Like you say, probally not worth spending money on,
especially as it looks like one of the previous owners used a gritty rag to
clean it.

Hope this helps,

Cheers.

Pete

--
http://www.petezilla.co.uk

On 12 Nov, 09:32, Peter Chant
wrote:
krishnananda wrote:
Can you see if the deposit is between 2 lenses in a group or is on a
glass-air interface? If the first it is probably separation/cement
failure. If the second is can be fungus or another deposit. Fungus can
be abated with the lens-in-the-sun trick, but that doesn't always take
care of the problem.

Hard to say exactly where it is. Just blasted the lens with a UV lamp,
though as the UV lamp is probally intended for parties etc I'm not sure it
is short enough wavelength to do the trick. Can't do any harm though.

If it is separation you should probably consider replacing the entire
lens -- C330 lenses aren't that expensive. If it is some kind of deposit
a good camera repair shop should be able to clean it.

Suspect it is the latter - I've heard the fungus described as 'snowflakes'
etc, and it is nothing like that. I suppose the best bet is to just keep
using it unless I become unhappy with the images it produces. If it does
go too far I could try swapping the viewing and taking lenses, nothing to
loose at this point. Like you say, probally not worth spending money on,
especially as it looks like one of the previous owners used a gritty rag to
clean it.

Hope this helps,

Cheers.

Pete

--http://www.petezilla.co.uk

Fungus starts out innocent-looking, from what I have seen of old
cameras, as a smear of grease. Later the grease forms into blobs and
the blobs sprout filaments and then you know you have fungus. If
caught at the "smear of grease" stage then it might clean off without
any problems, though, if on a coated lens, it might have adversely
affecting the coating somewhat.

RolandRB wrote:

Fungus starts out innocent-looking, from what I have seen of old
cameras, as a smear of grease. Later the grease forms into blobs and
the blobs sprout filaments and then you know you have fungus. If
caught at the "smear of grease" stage then it might clean off without
any problems, though, if on a coated lens, it might have adversely
affecting the coating somewhat.

It was muck on the front of the rear element.

Well, probaly foolishly, I tentatively unscrewed the front of the lens, on
the basis of if it looked complicated I'd put it right back. All the glass
elements came out and it was a simple job to remove the assembly holding
the rear element.

Looking at the viewing lens there is similar muck on the front of the rear
element. This one is a lot stiffer, I need to get a bit more purchase to
take it apart.

Bit worried how muck, 'smear of grease' gets inside the lens like this.

Pete

--
http://www.petezilla.co.uk

On 12 Nov, 20:54, Peter Chant
wrote:
RolandRB wrote:
Fungus starts out innocent-looking, from what I have seen of old
cameras, as a smear of grease. Later the grease forms into blobs and
the blobs sprout filaments and then you know you have fungus. If
caught at the "smear of grease" stage then it might clean off without
any problems, though, if on a coated lens, it might have adversely
affecting the coating somewhat.

It was muck on the front of the rear element.

Well, probaly foolishly, I tentatively unscrewed the front of the lens, on
the basis of if it looked complicated I'd put it right back. All the glass
elements came out and it was a simple job to remove the assembly holding
the rear element.

Looking at the viewing lens there is similar muck on the front of the rear
element. This one is a lot stiffer, I need to get a bit more purchase to
take it apart.

Bit worried how muck, 'smear of grease' gets inside the lens like this.

Pete

--http://www.petezilla.co.uk

If the lens was ever in warm humid conditions and then later cooler
the condensation would come out of the air and settle on the lens
surfaces inside. I guess it would more readily condense on fungus
spores.

RolandRB wrote:


If the lens was ever in warm humid conditions and then later cooler
the condensation would come out of the air and settle on the lens
surfaces inside. I guess it would more readily condense on fungus
spores.

Reasonably well sealed, so I can't see you getting much in the way of
condensation. Packed in plastic bag with dessicant just in case. Ought to
shoot a test film before much longer.

Cleaned surfaces with vinegar, as suggested on a website somewhere, as it
kills fungus (use at own risk!), and reassembled.

For the viewing lens the front of the rear element looked reasonably clean
until I breathed on it, it was obviously splodgy and dirty. What looked
like a couple of scratches and a few other marks would not clean off.
Would have taken a photo but have not got DSLR and no film in film SLR's at
the moment.

Hopefully that's the end of it.

Pete



--
http://www.petezilla.co.uk

Peter Chant wrote:
RolandRB wrote:


If the lens was ever in warm humid conditions and then later cooler
the condensation would come out of the air and settle on the lens
surfaces inside. I guess it would more readily condense on fungus
spores.

Reasonably well sealed, so I can't see you getting much in the way of
condensation. Packed in plastic bag with dessicant just in case. Ought to
shoot a test film before much longer.

Cleaned surfaces with vinegar, as suggested on a website somewhere, as it
kills fungus (use at own risk!), and reassembled.

I would imagine that vinegar kills lens coatings as the coating is
alkaline (as is the glass in lenses).

For the viewing lens the front of the rear element looked reasonably clean
until I breathed on it, it was obviously splodgy and dirty. What looked
like a couple of scratches and a few other marks would not clean off.
Would have taken a photo but have not got DSLR and no film in film SLR's at
the moment.

Hopefully that's the end of it.

Pete



--
http://www.petezilla.co.uk

RolandRB wrote:


I would imagine that vinegar kills lens coatings as the coating is
alkaline (as is the glass in lenses).


Pity I did not remember the web page - the guy who wrote the page gave the
impression he knew what he was on about. No, did not appear to damage
coating. However YMMV.

By the magic of Google: http://www.mypentax.com/Fungus.html compared to
hydrogen peroxide and ammoina and _soft_ metal polish vinegar is likely
quite mild.

Pete


--
http://www.petezilla.co.uk

Peter Chant wrote:
RolandRB wrote:


I would imagine that vinegar kills lens coatings as the coating is
alkaline (as is the glass in lenses).


Pity I did not remember the web page - the guy who wrote the page gave the
impression he knew what he was on about. No, did not appear to damage
coating. However YMMV.

By the magic of Google: http://www.mypentax.com/Fungus.html compared to
hydrogen peroxide and ammoina and _soft_ metal polish vinegar is likely
quite mild.

What you are seeing sometimes is advice about fungus that applies to
old cameras with lenses that were made before coatings were introduced.

RolandRB wrote:

What you are seeing sometimes is advice about fungus that applies to
old cameras with lenses that were made before coatings were introduced.

Well, a bit late now, but it appears not to have done any harm. Interesting
to note, in eighteen years of wearing glasses with coated lenses I've only
once had a problem with something attacking the coatings on one pair, and
that was a long time back - something quite nasty.

Pete

--
http://www.petezilla.co.uk