How balsam separation could effect the imagine.

[P.Esquerdo]

Good morning/evening to everyone,

Recently, I'd been interested in 40's-60's lenses to obtain a different look at my pictures, especially portraits. Many of them have premium prices but sometimes appear affordable (around 30-25% of the price for good one) lenses with some issues. Some of those lenses are prone to have lens separation due to materials used in the element glue. I know this is not common in lenses upper the 70's.

I had/have some with scratches, haze and fungus. Meanwhile Im not able to see any issue with scratched lenses, haze and fungus can reduce the sharpness and especially the contrast.
But I'd never tried a lens with balsam separation to aware how can effect to the picture. Just to feed my curiosity and be aware in the future if there is some worthy deal.

Thank you for your time.

[arri]

I have a few lenses with separation, f.ex. a Rodenstock Sironar 180mm f/5.6
I can´t see any different between this lens or a Symmar S 180mm.
I called Rodenstock a lot of years ago to get information about this issue.
They told me that this kind of separation have no optical effect, the quality of the results are identic to a lens with no separations.
The reason is that the gab is smaller than a half of the wave length of the visible light and so it can´t influence the optical design.
Only the speed of the lens is reduced a little bit, in 1/100 grades of f/stops.

Maybe someone has other information but my experiances with this lenses are like descriped above.

I enlarge my 6x6cm and 4x5" prints with Rodenstock Rodagon lenses, the 80mm Rodagon has a front element with 80% separation but it is as sharp as the prints I made with a 80mm Componon S from Schneider I got from a friend for compare both lenses. The same with the 135mm Rodagon.

I bought the 80mm Rodagon for 15 Euros and the 135mm for 25 Euros because of the lens separation.
For me it were very good deals, I don´t need this lenses only for working and not for repesentation.

[P.Esquerdo]

Thank you for your reply.

Rodenstock is the first brand that come on mind, I guess isnt the only brand with that problem. Where I live, I'd seen some months ago a Rodenstock Sironar 150mm f5.6 for 80 euros in the coin exchange, with that issue. I was tempted but at the end I skipped.

[Kevin Crisp]

Lenses with balsam cementing, post WWII, are pretty rare. Even though hundreds of Ebay sellers talk about balsam in their ads for more modern lenses. The answer to your question is ----- it depends. I've had a couple early Symmars that had what people commonly call "snowflake" separations. A small spot that indeed looks kind of like a shiny snowflake. A lens with two of them performed really well for me for many years and it never got worse.

If the separation is on the edge in a modern lens, I'd be very concerned that it is going to spread. It often has a rainbow like appearance. The lens was probably mistreated at some point, as in left in a hot car trunk. Some lenses considered highly desirable do have this issue, such as the Rolleiflex 3.5 Planars. I have one of those which looks great until you shine a bright light through it and you can tell the cementing across a lot of the lens is failing. This has a huge effect on the image. It is technically sharp, but contrast is low and there is a fuzzy blooming around all highlights. It is an interesting effect.

The problem with your question is the variability of the effect. Until you buy a particular lens and try it out, you aren't going to know.

[ic-racer]

I did some testing with a lens that had circumferential 2-3mm uv/glue separation round the periphery of a glued pair, compared to the same lens without the separation. In the very corners there was a subtle loss of sharpness. Maybe the difference between a great lens and an OK lens. The test subject was landscape photography. For portraits, I don't see how it would matter unless the edges of someone's face were up against the corner of the frame.

[arri]

There are different kind of separation.

The lenses, cemented with Canada balm have different separation than the later lenses which are cemented with UV hardened lens glue.

The Canada balm cemented lenses have mostly a separation from outside to the inside. It happens when alcohol /ethanol or acetone were used for the cleaning. The dead for the lens cement.

The lenses with the UV glue can have separation inside the lens surfaces not only at the edges. The reasons are the tensions inside of the glass, this broke the cementation but the resulted gab is really small, it breaks the light beams and that is the reason why you see the rainbow colours. It can´t have any negative influence to the optical quality.

[Dan Fromm]

There are different kind of separation.

The lenses, cemented with Canada balm have different separation than the later lenses which are cemented with UV hardened lens glue.

The Canada balm cemented lenses have mostly a separation from outside to the inside. It happens when alcohol /ethanol or acetone were used for the cleaning. The dead for the lens cement.

The lenses with the UV glue can have separation inside the lens surfaces not only at the edges. The reasons are the tensions inside of the glass, this broke the cementation but the resulted gab is really small, it breaks the light beams and that is the reason why you see the rainbow colours. It can´t have any negative influence to the optical quality.

I beg to differ.

I once bought a 16/2.5 Luminar. The cemented elements were cemented with Canada balsam. The lens appears to have been baked front down in an oven. I saw voids in glass-cement-glass interfaces and balsam was puddled around the edge of the front element. Image quality was terrible, much much worse than a good 16/2.5 that I borrowed.

I have a Kodak 25-15 converter for the 25/1.4 Cine Ektar. The converter's elements are cemented with a synthetic. It has severe separations, with very visible Newton's rings. Footage shot with the prime lens plus the converter shows the rings very clearly. The converter is completely unusable.

[Kevin Crisp]

Example of highlight "bloom" on a failing Zeiss 75mm Planar.