Ken Durling wrote: > > On Sat, 20 Oct 2001 09:44:53 -0700, you wrote: > > >What would be the benefit of that? If it's magnification, how would I > >calculate the magnification it would give me? > > > >Gerry > > Gerry - > > I confess the math of this escapes me, although I've never really sat > down to crack it. Magnification is generally better than 1:1 with a > "normal" lens, i.e from 40-60mm. It has to do with symmetrical vs > asymmetrical lens design, pupillary magnification and such. There are > probably guys on this list that can explain it! > > There is a brief explanation of it in the Kodak Workshop series book > on Close-up photography.
This is mainly useful for use with a bellows. Reversing the lens has the reason, that lenses normally are corrected for relatively small magnifications, or, IOW, big focusing distances of at least 100 x focal length or even more. So, in theory, if you reverse the lens, the correction will work better for very big magnifications beyond 1x. Typically one uses a wide angle lens on a bellows, with a longer focal length you'll need a lot of extension, which isn't very practical. To sum it up, the reversed lens won't give you more magnification than the lens used the normal way, if you use it on a bellows. It's just the correction of the lens is better with the lens reversed when you go beyond 1x magnification. Thomas Bantel * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
