Hi this is Lonnie: I have a question about your answer to Bill about pinhole exposures @ f/500 with ISO 100 film.
Looking at my light meter without any reciprocity corrections a sunny f/16 exposure should be about 8 seconds @ f/500. If you have heavy sun as well as bright snow I would use 4 seconds as my base for an exposure. The 8 seconds @ f/500 would be EV 15 The 4 seconds would be EV 16. Lonnie