Fazal Majid has posted a useful look at loupes on his weblog, inclduing models from Peak, Contax and Schneider.

“Loupes (French for “magnifying glass) are high-quality magnifiers, originally used to help focus images on a ground glass, and later to view slides or negatives on a light table. You can find them in all shapes and sizes, at prices from $15 for a cheap plastic model, all the way to over $300 for a Zeiss loupe for viewing 6x6 medium format slides. Slides viewed on a light table with a high-quality loupe are a treat for the eyes, because of the high contrast (1000:1) that you cannot get with prints (more like 100:1).”

Website: Going all loopy about loupes