Hi,
In this thread http://www.birdforum.net/showthread.php?t=42635 about fogging Ultravids (focus wheel windows really), Otto McDiesel wonders if this could have something to do with pressurized cabins on airplanes.
Which brings up an experience I had with a pair of Zeiss West 10x50 porro's bought about a month ago, which appeared to me initially of lower image quality than I expected. They were not as sharp as I thought they would be, and slightly hazy when used in bright sunlight. My impression was that they were more sensitive to hazy and humid air conditions than my other binoculars, which cut through the muck more easily.
When I examined them scrupulously I couldn't find anything wrong with the lenses or prisms - these were as clear as I could wish for. I found one thing though in the eyepieces: seen from on angle on the ocular lense there was a kind of disc of haze or dust visible. Its structure was so fine I couldn't see it when viewing straight into the eyepiece, nor could I find it from the objectives end.
Now, these binoculars are not multicoated and so one would expect them to be less contrasty, a bit duller and darker than modern binoculars. My problem was however that I couldn't attribute its performance exclusively to that. So I contemplated to have them professionally cleaned to be certain.
But what happened, after a few weeks I noticed my Zeisses seemed to become better and better. Also, I couldn't find the 'hazy disc' anymore. At the moment they are so fine, with a rendition of colour in low light so good, that I'm certain their performance is absolutely on par. What's not ideal in comparison can be explained perfectly by the lack of coating.
So maybe this air pressure on transport could have something to do with it? I'm not certain because lighting conditions have changed too (autumn), and maybe I've just learned to exept them for what they are.
Question: anyone else with the same experience, or doubts?
Renze de Vries
yeah, altitude and pressure can affect bins
my mates swarovs fogged inside after going from sea level in the Amazon up to 4000 m in the Andes in a day.
my Zeiss ClassiCs were unaffected
Tim