Canon 50mm f/1.2 LTM severe haze - permanent etching or cleanable?

[robonfilm]

Hi everyone,

I recently acquired a Canon 50mm f/1.2 LTM, but unfortunately, it suffers from the usual very heavy internal haze.

Looking through the glass, it's not just a light, uniform milky fog. As you can see in the photos below, it has a dense, textured, almost "bubbly" appearance. It seems to be located on the element immediately adjacent to the aperture blades.

I know this specific lens is notorious for the outgassing of the original lubricants, and I'm worried this might be permanent glass etching rather than just a cleanable layer.

I have 99% isopropyl alcohol, and I am comfortable doing careful DIY work to open the optical block. However, before I take the risk of opening it and potentially messing with the collimation/shims, I wanted to ask the experts here:

• Has anyone successfully cleaned this specific type of textured haze on this exact lens?
• Or is this a textbook example of permanent chemical etching that would require professional re-polishing and re-coating?

To be completely honest, I am on the fence about keeping this lens regardless of the outcome. I already own a Canon 50mm f/1.4 LTM in great condition which I use daily. If trying to clean this f/1.2 is likely a lost cause (or if it requires sending it to Kanto for a very expensive restoration), I might just prefer to sell it "as-is" for parts or repair.

Any insights, opinions, or personal experiences with this specific issue is greatly appreciated!

Thanks in advance.

 

[Nicholas Lindan]

I don't have any experience with this particular lens.

However, it doesn't look like any haze I have ever seen. It looks more like condensation. If so, it gives new meaning to "this lens is notorious for the outgassing of the original lubricants."

It would, of course, be extremely interesting to know just what this is.

 

[film4Me]

Does it ever change or does it remain the same over time? Condensation changes. If it is that, usually warming the lens with a hair dryer on low heat will evaporate the moisture, but the moisture must be allowed to escape the lens, so it could take some time before you'll notice a difference.

They might be oil droplets, in which case the lens will need to be disassembled and cleaned with lighter fluid or isopropyl alcohol, and finally Windex for the glass elements.

I don't recognize it as fungus, but I've seen some weird things happen to lens glass. Fungus can come in many forms, however, I've never seen it in the form of droplets uniform over the entire surface, so whatever those "droplets" are, they will probably clean off, or evaporate off.

 

[robonfilm]

It looks more like condensation

It's difficult to describe, but it looks like a 'dry' film.

Does it ever change or does it remain the same over time?

No, it stays like that.

 

[Andreas Thaler]

I don't have any experience with this particular lens.

However, it doesn't look like any haze I have ever seen. It looks more like condensation. If so, it gives new meaning to "this lens is notorious for the outgassing of the original lubricants."

It would, of course, be extremely interesting to know just what this is.

I agree with Nicholas. It looks like the condensation of oil-laden vapors. The structures seem too uniform to me to be fungus.

 

[RalphLambrecht]

Hi everyone,

I recently acquired a Canon 50mm f/1.2 LTM, but unfortunately, it suffers from the usual very heavy internal haze.

Looking through the glass, it's not just a light, uniform milky fog. As you can see in the photos below, it has a dense, textured, almost "bubbly" appearance. It seems to be located on the element immediately adjacent to the aperture blades.

I know this specific lens is notorious for the outgassing of the original lubricants, and I'm worried this might be permanent glass etching rather than just a cleanable layer.

I have 99% isopropyl alcohol, and I am comfortable doing careful DIY work to open the optical block. However, before I take the risk of opening it and potentially messing with the collimation/shims, I wanted to ask the experts here:

• Has anyone successfully cleaned this specific type of textured haze on this exact lens?
• Or is this a textbook example of permanent chemical etching that would require professional re-polishing and re-coating?

To be completely honest, I am on the fence about keeping this lens regardless of the outcome. I already own a Canon 50mm f/1.4 LTM in great condition which I use daily. If trying to clean this f/1.2 is likely a lost cause (or if it requires sending it to Kanto for a very expensive restoration), I might just prefer to sell it "as-is" for parts or repair.

Any insights, opinions, or personal experiences with this specific issue is greatly appreciated!

Thanks in advance.

If you are comfortable with opening lenses, I'd give cleaning the glass a try!

 

[reddesert]

It's certainly not fungus, I believe the question the OP is asking is: is this a film/droplets (oil or whatever) deposited on the lens that can be cleaned off, or is it a reaction between the oil-or-whatever and the lens surface that has left permanent damage?

I don't have any experience with this lens; the Canon 50/1.8 rangefinder lens of a similar vintage is also known for haze issues, and it was my understanding that in some/many of the affected lenses, it's permanent rather than something that can be cleaned. However, I have not tried opening/cleaning one myself.

If you are confident in knowing how to open the lens and get at the surfaces, you can probably get it back together correctly, so IMO you are ahead of most potential purchasers of the lens.

 

[film4Me]

This is the only lens construction I could find for a Canon 50mm f1.2 - Hope it helps to understand where the haze might be. Do you think it's the same lens as your's?

 

[robonfilm]

For those who might be interested, I just tried cleaning the element, but unfortunately it seems the glass is permanently etched. Nothing could make it transparent again.