Hasselblad provides many choices for close up work, ranging from Proxar auxillary lenses, extension tubes (including a variable extension tube), bellows for really close up and high magnification work, as well as macro lenses.
Originally Posted by Snapper
I opted for the extension tube approach, and have 8mm and 21mm tubes. These work well on the 80mm Planar and the 150mm Sonnar. You can use the extension tubes in combination to get greater magification ratios. But you will need to modify exposure depending on the extension. You can calculate the exposure modification from the following
f/number to be used = aperture taken from light mete reading x(focal length of lens/focal length of lens + extension)
Example using a 56mm tube with 80mm lens with light meter indicating 1/60th @ f11.
f/number = 11x(80/(80+56)) ~ f6.47 which would be somewhere between f5.6 and f8.0. If you need greater depth of field just alter the exposure to get the f-stop you need.
Hope this is clear