>What's the idea behind contemporary lens hoods that look like a >flower blossom as opposed to older style lens hoods like the >collapsible rubber ones?
More efficient. If the film surface was round, a round hood would be perfect. A square film format would asks for a square hood or a symetrical "tulip" hood. A rectangular film format like 24X36m asks for a rectangular hood or an assymetrical "tulip" hood. If you put a round hood on a 35mm format lens, it will be as long as the hollow of the "tulip" hood. All the "petals" are there to cut unwanted light from reaching the lens. Rectangular hood are as good but it's not always possible to reverse them on their lens in order to pack you kit, so round "tulip" hood are favored now. ANDRE -- - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .