There are two brands that make "zoom" rubber hoods, Hoya and Hama. Hoya is lighter and starts at 35mm (to 210mm) while Hama is sturdier and starts at 24mm (to 210mm). Hoya is easier to use, because Hama ask you to unflod part of the rubber to get some of the lenghts. But they are not as dynamic as I and you would like, Cotty...Just moving onto zooms. Anyone thinking about the mechanics of a zoom lens will have surely pondered that the lenshood of such an optic will have to be a compromise. Now, if you have a 28-70 mm (say), then you will have deduced that the(fixed plastic or metal) hood is really a 28mm hood and nowhere near good enough to use at the 70 mm end. If you used a hood suitable for the 70mm end while 'zoomed out' at 28mm, you would suffer vignetting (dark corners of the frame) as the hood intruded on the picture.Of course, the answer is to alter the lenshood as the zoom lens focal length is altered. Fixed hoods cannot do this - a bellows hood can, and is really the only suitable answer to this particular problem. Anything else is generally a compromise. Someday, somebody will invent a dynamic dedicated hood for zooms, so that the length and shape changes as you zoom :-)
Andre
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