In article <1996Jan25.074825.10644@driftwood.cray.com>, george@sequoia.cray.com says...

>I would like to do close-up work with my Canon Elan, but I am trying
>to avoid the expense of a real macro lens. I have used the Tiffen
>close-up filters, but I am dissatisfied with the sharpness of the
>images. (....)
>If I need to bite the bullet and buy a real macro lens can anybody
>let me know his/her experiences with less expensive non-Cannon
>lenses like the Sigmas.

Since you are using zooms, I would recommend looking into an
achromat (fancy close-up lens) made by Canon (and Nikon and
others) - and I would probably get the strongest one they make
(which will provide reasonably close focus with the longer zoom
at its long end). These need to be used with the lens well
stopped down, but they can provide excellent results with zooms
(tubes often do not). If you go the Sigma macro route, the
90mm Sigma is one of the very few off-brand lenses that I
recommend (and it comes with an excellent achromat that can
be used on other lenses).
Hope This Helps