Performance at full aperture, apart from very obvious vignetting, especially at 24mm, was actually better with the Canon 5D than with the Canon 20D. Although edges are still a little soft at all focal lengths they’re not terrible. Stopping down to f5.6 cures the problem except at 85mm where they’re still a bit soft even at f8. Central performance at f5.6 and on is excellent.

This is a lovely lens to use so I’d say it would be fine to use with the Canon EOS 5D as a cheaper alternative to the new Canon 24-105mm f4 IS supplied as the Canon EOS 5D’s kit lens.

This lens performs far better with the Canon EOS 5D than with the Canon EOS 20D, which is something of a surprise, as with most lenses, performance is better with the smaller sensor. Overall performance with the Canon EOS 5D is very good, so if your bank account won’t quite stretch to the Canon 24-105, this isn’t a bad option.