High Altitude Exposure & Color Film

After a delay of a year, a friend of mine & I are getting ready to head to the Everest Base Camp and Gokyo Ri. We will be spending a fair amount of time at 5000m+ and we are both worried effects of UV, etc on color film. I have read that there can be a shift in color at altitude due to UV exposure, but have found nothing concrete. Is any special filtration required or I am just being stupid.

Gary

Some of the most incredible shots from Everest I've ever seen were done with an Olympus XA. I dont recall seeing any info on filters, mainly because there isn't any way to affix a filter on one. I would take a uV and a polarizer just to start, maybe check with Cromatek (or any other good filter mfg.) for proper info.

Rick

I second the suggestion for a polarizer. That will also eliminate UV from the light path. I find no problems at 3 Km altitude here in New Mexico, but you can certainly expect very high light levels on clear days. It is always a good idea to bracket exposures in unfamiliar lighting.

I would only worry about it with transparency film that you intend to directly project. Anything else will be easily correctable. Nonetheless, as long as your lenses are hooded, and you keep it clean, a UV filter won't hurt.

You're not being stupid. There's more UV at altitude to worry about, and it's not like you can shoot a test roll or just hop on over for a reshoot.

Most modern daylight balanced C41 and E6 films are not very sensitive to UV light, and the multicoated surfaces on modern optics stop UV as well. So for the vast majority of shooters a UV filter isn't needed.

That said, here I might make an exception. if you are planning to use Velvia with 1970's optics or fairly simple lenses like a Tessar or a Double-Gauss design, I'd personally use a UV filter. At least "old" Velvia had a rep for being UV sensitive, no matter what the data sheets showed.

I did a recent test which showed that a B+W 010 MRC UV filter blocked about 1.8% of the incoming light and caused about 25 degrees K of warming. That's not a huge downside. Of more concern in the increased likelihood of flare. So use a lens hood and consider removing the filter when there's a light source either in or just outside the frame.

Kodak made a set of HA-1, 2 and 3 filters for High Altitude work in color. They are graded with increasing UV absorption as you go up in altitude. I highly recommend you use as much UV filtration as you can tolerate. You should be concerned about short and long UV both and they get worse as you go up. Your altitude of 5000 meters should be handled by a normal UV filter with a yellowish color, but if it is clear, it is probably not robust enough.

There are several threads where this is discussed in detail.

PE

I shot Velvia 50 at 13,000+ feet in Peru last summer without a UV filter, and both long-distance and close-range images were fine (as in, I got exactly the color balance I would have expected at 'normal' altitudes). Equipment was mostly modern Nikon AF lenses, though I also had a '70s 100mm Series E.

I have the book and DVD film of the first conquest of Everest in 1953...gorgeous pictures, all on original 10ASA Kodachrome, and the stills with a Leica. I'm sure they would be difficult to improve on with modern equipment and films.

It would be interesting to know what, if any, UV filtering was used...I'd guess there would have been something? But certainly it is a must nowdays, using the advice already posted.

My own preference would be to not use polarising filters all the time if you're looking for a natural record....certainly inky-blue skies can look very dramatic, but too many pola shots can seem a bit obvious and overdone (IMHO).

Thank you all very much for the input. I always carry, though hardly use a PL filter, so it will be in the bag.
Now I just need to decide my gear list.

Best!

Gary