I have found the best lens hood to be the compendium lens shade that was made for my camera (Cambo). But it is big and can seem a bit cumbersome to work with. When in a rush I use what a lot of other use: dark slide or hat. On some of my older lenses I use series filters and the associated series lens shade.... and occassionally a screw-in rubber lens hoods, like one uses on 35mm. Anything is better than nothing.
I own a Fuji 250mm and a Schneider 121mm. I use a dark slide but Brian is probably right about a compendium shade being best. It is something else you have to carry with you though.
Alas, poor Yorick! I knew him, Horatio; a fellow of infinite jest, of most excellent fancy, or extensive depth of field; he hath borne me and my viewcamera on his back a thousand times; and now, how abhorred in my imagination it is! My gorge rims at it. Here hung those lips that I have kissed I know not how oft. Where be your lens shade now? Your compendium? Your film holders? Your flashes of photographic vision, that were wont to set the table on a roar?
Alas, poor Yorick! I knew him, Horatio; a fellow of infinite jest, of most excellent fancy, or extensive depth of field; he hath borne me and my viewcamera on his back a thousand times; and now, how abhorred in my imagination it is! My gorge rims at it. Here hung those lips that I have kissed I know not how oft. Where be your lens shade now? Your compendium? Your film holders? Your flashes of photographic vision, that were wont to set the table on a roar?