Originally Posted by rodi
bronica made some extension tubes, but i remember reading about some limitations, as well as the final affected aperture. does it alter anything besides focus distance? i really like this method, though. cheap and quick and small, we'll see what happens whenever i decide to shoot into the sun.
Depending on the length of the tube, you lose some light, like an f-stop for a 25mm tube on a 35mm camera. With your MF cameras, I don't know the light loss, but you could probably find out in one of the MF forums over at some place like photo.net.
I find my ETs easier to use with my longer lenses. On my 500mm, cutting the minimum focus distance from 12-ft to 8-ft is huge and then I add my TC, which has no impact on MFD, and I've got a bee filling the viewfinder at 8-ft. I use it a lot with my 70-200mm also. I'm shooting at around f/8 when all that stuff is piled on an f/4 lens.
I saw some amazing macros taken with a 65mm macro lens, two ET and flash. The guy specialized in macros and had a complex lighting scheme, but the results were stunning.
I've got both ETs and diopetor lenses and like them both. ETs are a cheap solution on dslr, but perhaps not so much for MF.