Is this balsam separation? (Canon 50/1.8 LTM, images)

[csmithstack]

Hi! New member here, just getting started in the world of adapting old rangefinder lenses to my digital x-pro 2. ... might be a gateway to film?

Anyhow, I just received my first old lens from e-bay--a type III (I think) Canon 50mm f/1.8. The seller (in Japan) seemed knowledgable enough and trustworthy. It was described as having "no balsam separation," but upon receipt of the item, I looked through the front element in regular daylight (no flashlight necessary, and saw a sort of refractive sparkle around the entire perimeter of one of the middle elements (behind the aperture, I believe). I've done what I can to take a representative image of what I'm seeing, but I've got a baby strapped to my chest, so couldn't quite attain perfection! 😱 I think it reflects what I'm seeing pretty clearly, though...

Does this seem like balsam separation to anyone here? Or something else worthy of note? The lens has clearly been CLA's in the past, so maybe it has something to do with that... I've looked around the net for images and examples and nothing seemed to match what I'm seeing here.

I paid about $200 for this, so don't expect perfection, but would have preferred one of the examples with haze or fungus and _no_ separation for a similar price--those seem easier for me to deal with on my own.

Thank you for your thoughts! I'm finding this forum to be a great resource.

 

[csmithstack]

... followup question... If this is separation, how quickly does this sort of thing progress? If it take years to become a problem, I might just go ahead and keep it. Thanks again!

 

[Hatchetman]

are you talking about that yellowish crusty stuff? If so, no I don't think that is separation. Not sure what it is. ?

 

[02Pilot]

Doesn't look like typical separation to me. Even if it were, I wouldn't worry about it. I've got a lens with a big jellyfish-shaped separation right smack in the middle of the optics, and I have to work very hard to get it to have any visible effect on photos. Hasn't changed at all in the years I've owned it either.

 

[csmithstack]

are you talking about that yellowish crusty stuff? If so, no I don't think that is separation. Not sure what it is. ?

Yep! That bright yellow-green ring around the perimeter of the inner lens. Staring down the front element in daylight shows it in a thin ring all around the perimeter of that element. It's quite refractive--shines pretty brightly. It was the fact that I see it around the perimeter of the lens and its refractive character that made me think it might be separation. But upon closer inspection it _does_ look a little crusty or multi-faceted... shines almost like chipped glass? (Which I doubt it is!) I might need to break out my magnifying glass for this one...

I'm about to hand the baby off. I'd be happy to try and take more pics of that'd help...

Thanks again.

 

[csmithstack]

Doesn't look like typical separation to me. Even if it were, I wouldn't worry about it. I've got a lens with a big jellyfish-shaped separation right smack in the middle of the optics, and I have to work very hard to get it to have any visible effect on photos. Hasn't changed at all in the years I've owned it either.

Very helpful. Thanks! 😛

 

[xayraa33]

Yup, That is balsam separation, very common occurrence on that model of lens.

 

[Highway 61]

What xayraa33 said. This is typical balsam separation because the balsam has dried up and the balsam structure has changed itself into very small opaque crystals where you see what is called "golden droplets".

It can increase over time, but slowly. The "golden droplets" ring may become thicker and more visible in several years onwards. But it also can stay like this for decades if there is no oxygen getting between those two cemented elements and and no heavy series of sudden humidity and temperature differences where the lens is stored.

What is to be looked for on that model of lens is some evidence of fungus having etched the glass surface on the element of the rear group facing the aperture blades, even if the lens has been CLA'd in the past. Most of those lenses exhibit some haze on that element, which is often terrible acid fungus having etched the glass like a blade etches the ice.

This is a remarkable lens. If the element mentioned above is crystal clear and if the lens is overall very clean, keep it and use it. You won't be disappointed.

 

[x-ray]

It's not separation yet but it is balsam deterioration. Balsam crystallizes over time and that's what you're seeing. Separation is when it progresses more into the lens.

I've seen it in view camera lenses and had a couple of Turner Reich convertibles that it has progressed 7-8mm into the lens. Even then if you don't shoot wide open it's not likely to be any issue. These old lenses like Protars and Turner Reich are a hundred years old or more.

The question, how much would you pay for a pristine sample compared to this. It's not likely to progress quickly or may not get any worse but compared to a pristine one what difference in price is there. If you bought it as a bargain then I'd keep it if everything else was ok.

Separation won't necessarily look like that. Separation is usually where the cement has failed and there's a very tiny gap between the elements. It often is no more space than a fraction of the wavelength of light. This is why you often see rainbow patterns in actual separation. It's due to interference patterns much like newton rings.

 

[csmithstack]

What xayraa33 said. This is typical balsam separation because the balsam has dried up and the balsam structure has changed itself into very small opaque crystals where you see what is called "golden droplets".

It can increase over time, but slowly. The "golden droplets" ring may become thicker and more visible in several years onwards. But it also can stay like this for decades if there is no oxygen getting between those two cemented elements and and no heavy series of sudden humidity and temperature differences where the lens is stored.

What is to be looked for on that model of lens is some evidence of fungus having etched the glass surface on the element of the rear group facing the aperture blades, even if the lens has been CLA'd in the past. Most of those lenses exhibit some haze on that element, which is often terrible acid fungus having etched the glass like a blade etches the ice.

This is a remarkable lens. If the element mentioned above is crystal clear and if the lens is overall very clean, keep it and use it. You won't be disappointed.

Hmmm... Thanks! It's good to hear that this phenomenon can develop slowly, if at all. I didn't want to think I'd sunk my funds into a tool that was already on its last legs, (... or in need of a repair that would exceed the cost of the lens itself).

The inner elements do, indeed, look crystal clear when peering through them in daylight, but I do see a thin haze and some wiping marks when I shine an LED through them.

I'm not really worried that the separation will appreciably alter the quality of the lens' output, and so long as I can get at least several good years of use out of it I suppose I'll be happy! ... though this minor, residual haze might not be a good sign...? (Fingers crossed the old oil was cleaned out and replaced when this lens was (presumably) CLA'd...)

 

[csmithstack]

The question, how much would you pay for a pristine sample compared to this. It's not likely to progress quickly or may not get any worse but compared to a pristine one what difference in price is there. If you bought it as a bargain then I'd keep it if everything else was ok.

Yeah, I guess that's the question. I'd be 100% happy if this had been a bargain! But it was rated as "near mint" with "no haze, no fungus, no separation, no oil on aperture blades, mechanically functional," etc., and was being sold for the same price as other samples of the same vintage with the same (ostensible) attributes... so this isn't exactly what I thought I was going to get for the price I paid. I figured the "near" in "near mint" was due to aesthetic considerations, as it shows its age a bit.

That said, the rating system employed by sellers on e-bay remains unclear to me. (What does Excellent ++++++++ mean, vs Excellent +++++, or Near Mint - and Near Mint?) As far as I know, all the other "near mint" lenses with "no separation" and "no haze" have these minor examples of both as well, while the slightly less expensive examples which explicitly listed separation and haze suffer from them much worse. ... it's hard to say. I was definitely looking for a (truly) optically clean, relatively worry free lens and, in hindsight, would have happily paid a bit more for one had one been out there. (Or a bit less for this one, presuming the other "near mint" lenses of this vintage turned out to be healthier examples.) Being new to the marketplace, its clear I have yet to get my bearings!

In any case, the seller has a 30-day return policy, so I guess the thing to do now will be to take some pictures with the lens the my adapter arrives later this week. Something tells me I'll be plenty happy with it. Thin haze and balsam deterioration aside(!), it seems to be in great mechanical and optical shape. No marks on front or rear elements, no oil on blades or anything like that. I'll post back with examples once I've had a chance to put it through its paces.

 

[x-ray]

Some of the view camera guys are getting antique lenses and even some of the more modern that have separated and recementing them using new UV cements. If I had a junker to play with I'd give it a try, BUT!

If I were in your shoes I'd return it at their expense. It's not a rare lens so you should be able to find a much nicer one in time. The down side is a lot of these lenses are like me, aging quickly. I tell young folks, look in the mirror, you'll never be better than you are today. Everyday is a gradual downhill slide even for camera gear. Cheerful thought of the day.

 

[csmithstack]

Haha! Well put, @X-ray!

 

[x-ray]

When I was in college in the 60's I majored in chemistry and microbiology although never worked in the field. Canada balsam is what we used to prepare microscope slides. Canada balsam even deteriorated on our slides over time. It's slow but it happens.

You do know that Canada balsam that was used in lenses is nothing more than tree sap? It's what makes your balsam Christmas tree sticky on the trunk. It's closely related to rosin from a pine tree too.