I was shooting in about 10 degree weather at 7000 feet and the Copal #1 shutter on my 300mm Nikkor started acting funny. I generally shoot on T but after being in the cold for about 45 minutes, the T setting started acting like B with the shutter staying open only as long as I had the cable release pressed.

Back and sea level and warmer temperatures, I can't get the shutter to fail.

Is this typical of these shutters or does it need repair.

- Dan.