P3D Re: PHOTO-3D digest 3065

["mikael.anjou@xxxxxxxxxxxxxx" <mikael.anjou@xxxxxxxxxxxxxx>]

Marcus Warrington asked about small bubles in the lenses of his Realist
2.8. I guess there can be two reasons for this.
Do the bubbles look like miniature rainbows? I mean light reflection in all
colours, when you look at the lenses with the camera back CLOSED and
shutter open?
If this is the case, then the problem probably is what Marcus says, the
glue between two of the lenses. Many years ago Canadian balsam (or balm, my
English could be better, I know) was a widely used glue for optics.
Unfortunately, there are very small creatures that actually eat the glue,
but heat and moist are other threats.
Could this be repaired?
In theory yes. But practical problems arise, most important is correct
centering and spacing of the lens components. And in a stereo camera focus
length is very important; if the lenses do not match one of them will
produce a smaller picture than the other. And that ruins the 3d illusion.

BUT if the bubbles are small and appear to be frozen in the lens glass you
do not have to worry. This was a commonly reported problem with some
high-quality optic glasses. In fact I have read many statements that the
bubbles are a proof of high quality. I had a large bubble in my Zeiss
Planar 80 mm 2.8 lens made for Hasselblad in the sixties. No problems here.
Nowadays manufacting has improved; bubbles are rarely seen.
Good luck, Marcus, from

Mikael Anjou
Sweden






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