Wierd Rodagons.

[Tony Lakin]

I have old type 240mm and a 300mm Rodagon lenses which have been lying around in my workshop for a few years, I had some spare time so decided to revisit them give them a clean and see it they would be any good as backups to my more recent Rodagon and Componon lenses. I cleaned them carefully and they appeared to be reasonably bright but with a few surface scratches so I put them onto my 8x10 Devere and tried to focus them but the projected image is very hazy/soft with both, I took the lenses to my office and had a look through them at my desk lamp, I noticed a ripple effect (like looking through a waterfall) which appears to be in the front lens group of both lenses, I don't expect to be able to rescue the lenses (they cost me nothing) never having come across this before I am just curious to know what it might be, anyone any idea?

[Struan Gray]

I have seen this in non-optical glass which has been exposed to strong alkali (1 molar KOH solutions) for a few months. It's not likely to be the cause here.

Is it a surface effect (can you feel the ripples with a finger?). If not, I would suspect failure of the cement between two of the elements making up the front groups.

[IanG]

I've seen similar when moisture has got between the elements with Componon lenses. Luckily in my case the elements unscrewed and could be cleaned perfectly. It happens when a cold lens doesn't have time to slowly warm up before use, t's worst in cool humid condition, and it's been particularly humid recently.

Ian

[joselsgil]

I would save those lenses for portrait prints. Kinda soften up them thar wrinkles

[Tony Lakin]

Thanks for the suggestions guys, I have traced the problem, the rippling is on the front of the front element of both lenses and as they came from the same source I have to assume that they have been cleaned with a corrosive chemical, I will make a print with one of them out of curiosity.