Reverse Macro on a Canon 40D Questions

[ryan24wsu]

I'm interested in a budget macro for my 40D (which I love!-first DSLR).  I've read many posts, some from Bob himself, about reversing a 50mm and attaching directly to the camera.  My question is should I purchase something like an older 28mm manual wide angle (since wide angle give better magnification for macro) for $50 on ebay?  Or should I reverse the 50mm 1.8 EF lens i already own and lose the magnification and manual adjustments? I would like to have the control of a manual lens as the 50mm EF lens will lose its "auto" features; or so I have read. 


SO...If i go with the older manual lens, which old lens do I get to do reverse macro at a nice magnification with great optics? I would like to spend less than $100, or less if possible.

I read the FD's from canon don't have the best quality in combination with the 40d. Is this true? And are the optic qualities changed when reversing the lens for macro?  Sorry for the long post covering a couple topics.  And thanks in advance for any sound advice.   

[Bob Atkins]

FD lenses are wierd in that the manual aperture control won't work unless they are mounted on an FD body. I think they're fixed at about f5.6 when not mounted on a body. There are various cams and pins that have to be operated to stop them down.

Old Pentax M42 screw mount lenses often have a "manual/auto" switch. In "manual" mode they stop down when you adjust the aperture ring. In "auto" there's a pin at the rear of the lens which must be pressed to stop them down, though it can easily be glued or wedged so that the lens always stops down. Newer M42 lenses just have the pin.

They are ideal because they are plentiful, cheap and can even be used the "right way around" on an EOS body with an adapter.

I wouldn't worry about the optics as none of them are really designed to be used reversed and so none of them are optimized for such operation. Any of them should be OK when stopped down a bit.