Home

Please support mflenses.com if you need any graphic related work order it from us, click on above banner to order!
SearchSearch MemberlistMemberlist RegisterRegister ProfileProfile Log in to check your private messagesLog in to check your private messages Log inLog in

Is this balsam separation or something else? Kowa B&H
Post new topic   Reply to topic
Home   Manual Focus Lenses
View previous topic :: View next topic  


PostPosted: Fri Jan 12, 2024 1:55 pm    Post subject: Is this balsam separation or something else? Kowa B&H Reply with quote



PostPosted: Fri Jan 12, 2024 2:14 pm    Post subject: Reply with quote
Hard to say for sure from these images, but that does look like edge separation of the balsam. It happens on older lenses, especially larger diameter lenses (up to 3 inches or so, above that you are unlikely to find cemented doublets).

Don't panic yet; often this does not progress any further if you don't subject the lens to rapid or large temperature changes.

Usually this is only visible in the bokeh-balls of out-of-focus spotlights. Depending on the mechanical construction of the optics it may not be visible in the images at all.

I am not sure how much more susceptible an anamorphic lens like this may be to further degradation of the balsam separation.


PostPosted: Fri Jan 12, 2024 2:17 pm    Post subject: Reply with quote
RokkorDoctor wrote:
Hard to say for sure from these images, but that does look like edge separation of the balsam. It happens on older lenses, especially larger diameter lenses (up to 3 inches or so, above that you are unlikely to find cemented doublets).

Don't panic yet; often this does not progress any further if you don't subject the lens to rapid or large temperature changes.

Usually this is only visible in the bokeh-balls of out-of-focus spotlights. Depending on the mechanical construction of the optics it may not be visible in the images at all.

I am not sure how much more susceptible an anamorphic lens like this may be to further degradation of the balsam separation.



Unfortunately it does show up as a fairly large milky spot where contrast is low. This is when a light source hits it at a certain angle.


PostPosted: Sat Jan 13, 2024 2:05 am    Post subject: Reply with quote
As RokkorDoctor says, it's hard to tell from that photo, but that lens definitely has some pretty obvious thread-like fungus going on right around the larger milky spot, so it could simply be a larger patch of fungus sitting on an air-exposed surface, in which case, cleaning it might be a less onerous proposition, presuming the surfaces haven't become etched by the fungal excretions.

Typically, when you see cement separation ( I strongly prefer that term to "balsam separation," since the vast majority lenses later than the the early 1950's use synthetic cements rather than balsam) that begins in the center like that rather than the edges, it manifests as either general overall haziness or "florets," so I'm not entirely convinced that's what's going on here. There does appear to be some pretty minor edge separation, most obviously at the very left, that you'll note looks very different than the milky blob, so I think something else is going on here. I wouldn't worry about the edges at all, since on an auxiliary anamorphic lens like this, those areas will fall well outside of the imaging area projected onto your sensor/film.


PostPosted: Sat Jan 13, 2024 10:13 am    Post subject: Reply with quote
BrianSVP wrote:
As RokkorDoctor says, it's hard to tell from that photo, but that lens definitely has some pretty obvious thread-like fungus going on right around the larger milky spot, so it could simply be a larger patch of fungus sitting on an air-exposed surface, in which case, cleaning it might be a less onerous proposition, presuming the surfaces haven't become etched by the fungal excretions.

Typically, when you see cement separation ( I strongly prefer that term to "balsam separation," since the vast majority lenses later than the the early 1950's use synthetic cements rather than balsam) that begins in the center like that rather than the edges, it manifests as either general overall haziness or "florets," so I'm not entirely convinced that's what's going on here. There does appear to be some pretty minor edge separation, most obviously at the very left, that you'll note looks very different than the milky blob, so I think something else is going on here. I wouldn't worry about the edges at all, since on an auxiliary anamorphic lens like this, those areas will fall well outside of the imaging area projected onto your sensor/film.


Clearly we were looking at different issues;

I thought the OP was asking about the separation at the edges of the lens but they may well have been referring to the greyish patch in the middle of it (I had assumed it was some reflection, but may well be a mould patch).

Minolta may have held onto Canada balsam longer than other optics manufacterers; one 1961 vintage Minolta 58mm ROKKOR lens definitely had Canada balsam in the doublet; there was this familiar pine-resin smell as I gently heated and separated it...


PostPosted: Sat Jan 13, 2024 4:30 pm    Post subject: Reply with quote
RokkorDoctor wrote:
BrianSVP wrote:
As RokkorDoctor says, it's hard to tell from that photo, but that lens definitely has some pretty obvious thread-like fungus going on right around the larger milky spot, so it could simply be a larger patch of fungus sitting on an air-exposed surface, in which case, cleaning it might be a less onerous proposition, presuming the surfaces haven't become etched by the fungal excretions.

Typically, when you see cement separation ( I strongly prefer that term to "balsam separation," since the vast majority lenses later than the the early 1950's use synthetic cements rather than balsam) that begins in the center like that rather than the edges, it manifests as either general overall haziness or "florets," so I'm not entirely convinced that's what's going on here. There does appear to be some pretty minor edge separation, most obviously at the very left, that you'll note looks very different than the milky blob, so I think something else is going on here. I wouldn't worry about the edges at all, since on an auxiliary anamorphic lens like this, those areas will fall well outside of the imaging area projected onto your sensor/film.


Clearly we were looking at different issues;

I thought the OP was asking about the separation at the edges of the lens but they may well have been referring to the greyish patch in the middle of it (I had assumed it was some reflection, but may well be a mould patch).

Minolta may have held onto Canada balsam longer than other optics manufacterers; one 1961 vintage Minolta 58mm ROKKOR lens definitely had Canada balsam in the doublet; there was
this familiar pine-resin smell as I gently heated and separated it...



Sorry, I realise I wasn't quite clear. It is the greyish patch towards the center of the lens I was referring to as that's what's showing up in what I capture.


PostPosted: Sat Jan 13, 2024 7:03 pm    Post subject: Reply with quote
I've never seen any fungus / mould looking like that:



To me it looks either like

1) dirt (grease?) or
2) scratch / damaged coating

S
Post new topic   Reply to topic
Home   Manual Focus Lenses
Page 1 of 1