Most of my snow crystals are at that magnification or greater. I just use a 50mm reverse mounted on a bellows and set of extension tubes. The reverse mounted 50mm plus 100-150mm of tubes results in some mighty magnification. The reverse mounting is the key - it seems to keep subject to lens working distance more consistent than if the lens was not reverse mounted (forward mounted?)
Flash is really useful, and the problem might be that the camera is not able to deal with TTL flash either without the lens to body contacts or with the extension factor. If you don't use flash you will need to construct a very steady support system for the camera, and make sure that the subject is absolutely still (which might be a problem if they are in water.) If TTL flash does not work, the classic approach is to figure out how far away to place the flash taking into account the aperture, flash guide number, and exposure factor introduced by the extension. But with a digital camera - trial and error would probably be a better approach. Another idea is to reverse mount a lens in front of a telephoto. That should have no effect on metering or TTL flash - basically the reverse mounted lens is just acting as a close-up diopter. The basic equation is that magnification equals the main lens focal length divided by the focal length of the reverse mounted lens. So a 50mm lens reversed in front of a 200mm gets you to 4x lifesized. A fast 50mm reverse mounted on a 200mm with some extension tubes should get you to pretty high magnifications, not affect metering (assuming the tubes have the appropriate contacts for lens to body communication), and not result in severe vignetting. My experience has been that reverse mounting a shorter focal length lens in front of a 200mm results in vignetting, but I've only had f2.8 lenses to work work with. - MCC Leon Altoff wrote: > Hi all > > I have a friend who has a Canon 300D and I would like to try to help him > improve his macro photos of really small objects - down to approximately > 3mm in length. > > He currently has a Canon 100 mm f2.8 macro and a Canon ring flash. The > problem is that the subject - generally live marine animals in about 1cm > of water - in the resulting images is not large enough to blow up to a > usable size. > > I'm willing to take Canon specific suggestions as well as general macro > suggestions, but I don't know what is available for Canons in terms of > macro equipment, and it needs to work with his ring flash. I'll even > accept the address of another forum dealing with Canon macro photography > (Is there one?) or suggestion from Cotty on how to graft good Pentax > optics on to the Canon body. > > All help from those who tread the dark path (and I know you are out > there) will be greatfully accepted. > -- - - - - - - - - - - - - - - - - - - - - Mark Cassino Photography Kalamazoo, Michigan www.markcassino.com - - - - - - - - - - - - - - - - - - - - -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
