Balsam Deterioration / Lens Seperation efImage Quality

[Dave S.]

I recently picked up a nice Agfa Super Silette with the Solagon 1:2/50 in a Synchro-Compur shutter. Upon unscrewing the lens from the front of the camera and looking at it closely under bright light I noticed what appeared to be tiny bubbles spread fairly evenly across the lens. These bubbles seemed to be between the elements and did not clear with normal cleaning.

When the lens is on the camera the bubbles are not visible even when viewed under bright light (in fact the lens looks very clear). Based on some internet research I've done I suspect these bubbles are due to balsam deterioration / lens separation.

I have a couple of questions about this issue:

1. Does this sound like balsam deterioration / lens separation to others or is it perhaps something else?

2. If it is balsam deterioration / lens separation what kind of effect will this have on image quality (if any)?

Thanks, Dave

 

[tunalegs]

There would need to be a lot of bubbles before it would have enough of an effect to be noticed on a print. Up until the 1950s it was normal for the glass itself to have bubbles in it.

Usually separation happens from the edges in... but I have a very old box camera that has nearly uniformly spaced bubbles between the elements of its achromat lens.

 

[Sonnar Brian]

Typically you get a rainbow from Balsam separation- Newton's Rings. Bubbles- sounds like the glass. Shoot with the camera, see how it is on film.

 

[Steve M.]

What Brian said. Bubbles are probably just imperfections in the glass. Separation looks very different.

 

[f16sunshine]

I don't think it is separation either. Many of my old Zeiss lenses have tiny bubbles in the glass. One of the Biotars has many in fact. If IQ is effected I would never know having never compared to a non bubble version. IQ is superb in the case of the lens I have. Shoot it for a few rolls and see what you think.

 

[Frontman]

It can be a separation problem, I have seen this exact problem in several Pentax 105/2.4 lenses. Different lenses show different effects. In my old Summitar, it shows as a faint, greyish cloud around the edge between the front elements. It may or may not affect the pictures, bubbles generally have no effect, but I have had more flare issues with lenses which have separation problems.

 

[Beemermark]

Bubbles were pretty common with the manufacturing process. I even have a Leica brochure that talks about bubbles and why they have no effect on the image.

IMHO, people should spend less time looking thru their lenses with a 500 watt light and magnifying glass and just go take pictures.

 

[Dave S.]

Thanks everyone for all of your helpful responses.

Brian: Thanks for your comments regarding "rainbow from Balsam separation- Newton's Rings". This is not what I'm seeing in this lens so perhaps it's just bubbles.

It also sounds like balsam deterioration / lens separation is seen more around the edges of elements - even if sometimes it presents as more "faint, greyish cloud" than rainbow (thanks Frontman).

Beemermark: For me personally, I enjoy taking pictures and learning about the minutiae of classic cameras and lenses - stuff like balsam deterioration, bubbles in lens elements, etc. (in a kind of Zen and the Art of Motorcycle Maintenance way).

That said, I took your advice and have attached a few pictures of my Solagon 1:2/50. 😀

Does this look like bubbles or balsam separation?

-Dave

 

[Luddite Frank]

Thanks everyone for all of your helpful responses.

Brian: Thanks for your comments regarding "rainbow from Balsam separation- Newton's Rings". This is not what I'm seeing in this lens so perhaps it's just bubbles.

It also sounds like balsam deterioration / lens separation is seen more around the edges of elements - even if sometimes it presents as more "faint, greyish cloud" than rainbow (thanks Frontman).

Beemermark: For me personally, I enjoy taking pictures and learning about the minutiae of classic cameras and lenses - stuff like balsam deterioration, bubbles in lens elements, etc. (in a kind of Zen and the Art of Motorcycle Maintenance way).

That said, I took your advice and have attached a few pictures of my Solagon 1:2/50. 😀

Does this look like bubbles or balsam separation?

-Dave

The bright pin-points of light towards the center of the glass look like bubbles, or "seeds" as the window-glass people call them.

The cloudy-ish parts of the lens, around the lower part of the glass, say from about 1 o'clock over to 7 o'clock look like some other sort of deterioration - perhaps balsam, maybe fungal etching, or coating damage...

The "clouding" might cause some flare if you are shooting w/o a hood or against strong light....

Most of the balsam failure I have personally experienced has been with pre- WW-I lenses, and usually starting as a ring around the perimeter... stopping-down 1 stop usually masks the separation.

I do have a Takumar 55/1.8 from my 1960's Pentax SP-500 that has dramatic balsam failure, intruding nearly 1/2 into the center of the lens, about 60 % of the way around the glass...

Just my impression for looking at your pictures...

😎

 

[Dave S.]

Thanks for your comments Luddite Frank. I hadn't considered fungal etching, or coating damage. Regarding the "cloudy-ish parts of the lens" - that is really across the whole lens, not just the 1 o'clock over to 7 o'clock area. It's just the way the light is catching it only really brought out that area.

By the way, these pictures were taken under strong light, through the rear element, and I had to tilt the lens just right to make these issues stand out so I could capture and share them.

-Dave

 

[Beemermark]

The pin point specks are bubbles introduced in the melting process. The cloudiness is probably just haze, though it is hard to tell. The cloudiness will probably reduce the contrast but shouldn't affect sharpness (of course the perceived sharpness will be less).

 

[Chuck Albertson]

Don Ho Syndrome. It's well-documented in the literature.

 

[Dave S.]

Tiny bubbles (tiny bubbles)
In the glass (in the glass)
Make me happy (make me happy)
Or just a pain in my @#!? (or just a pain in my @#!?) 😉