3 ms·
If the lens does not breathe there would be no advantage (it can just be airtight without being vacuum) and if the lens breathes (ie changes internal volume) it
by lmilcin 7y ago
If the lens does not breathe there would be no advantage (it can just be airtight without being vacuum) and if the lens breathes (ie changes internal volume) it means the motor would have to work against atmospheric pressure which would be extremely difficult in a lens to do reliably.
- penagwin 7y agoCounter question: Why not fill lenses with Nitrogen? I know outdoor cameras CCTV cameras do this (more so to prevent condensation from internal moisture).
- grozzle 7y agoYou'd still have to compress the nitrogen going one way to zoom, and pull the nitrogen against air pressure going the other way. Focus motors powerful enough to do that, plus including movable airtight seals to keep the nitrogen inside, would make the lens a serious chunk bigger, heavier and more expensive. The dust that gets inside from breathing while zooming rarely affects image quality to any meaningful degree. Excessive humidity can lead to fungus growing on the glass though, which really can ruin your contrast. It's normally good enough to keep your lenses in a box with some silica desiccant during summer to prevent that.