WOW! Great thread. Since I do so much of my photography outdoors in all kinds of weather, this is a great read. In my experience, the biggest challenge is achieving adequate warmth to the fingers but still being able to use the camera controls without much effort. My solutions have evolved and change based on the situation, how cold and how long I'll be in the cold shooting. It may have already been said but this is some of what I do....
- Golf Gloves (For mild cool weather, low wind. They are thin and light.)
- Fingerless Wool (For cool to cold but not a long time.)
- Seirus - HYPERLITE™ ALL WEATHER™ GLOVE
(Best solution so far. Thin enough to wear under the wool fingerless if necc.)http://tinyurl.com/b3fkl5g
The Seirus Hyperlite
gloves I originally carried for hiking and trek pole use. But they are thin enough to work the camera and still warmer than other alternatives due to the use of high tech materials. They are designed for tactical gun use but also work great for holding trekking poles and cameras. I used them this past weekend on a hiking trip for several hours shooting pictures in nighttime astronomy upper 30's temps, low to no wind. Hands/fingers still got cold but only after an hour or more and very little exertion. They aren't a perfect solution but so far, I haven't found a *perfect* thin glove solution. (Where *perfect* means no long term finger/hand chill whatsoever.) You still need to alternate the hands/fingers in and out of a warm pocket every so often to maintain comfort.
Keep in mind, even thick wind proof Snow Ski Gloves will eventually allow your fingers to get cold. Mittens are the best way to keep warm but they are worthless for finger use. So a warm pocket can usually help you keep fingers warm if you keep your gloved hands in pockets or under arms when not in use.
In general, look for the use of high tech synthetic moisture resistant materials like PolarTec, etc. Stay away from cotton. Wool is good but not thin enough.