Geoff Rehmet wrote in article <3432AF11.4537@gfsa.co.za>...

> I'm looking around at the moment for a lens with a focal length up to
> about 400mm (possibly a 100 to 400mm), with a Canon EF mount (for an
> EOS). I'm quite happy with a Sigma 70-210mm lens which I already have,
> and would happily consider Sigma. What other brands are a good bet. --
> Does anyone have any opinions on Cosina lenses?

The Cosina 100-500mm (f5.6-8 rated, but it appears to be slower...)
that I have is excellent (quite sharp 100-400mm, and good out to
500mm, center-to-corner, even "wide" open), though it is often too
slow to be very practical, and it is quite large...
Hope This Helps
David Ruether - http://www.fcinet.com/ruether