The Canon EF 17-40mm 4.0L USM camera lens is compatible with most Canon EOS cameras, especially those with a focal length conversion factor higher than 1. This lens provides superb optical performance throughout the zoom range and has a 28cm minimum focusing distance at all focal lengths.
This Canon EF lens is highly dust and moisture resistant and features 12 spectra coated lens elements that come arranged in 9 groups. It offers excellent colour balance with a minimum of ghosting and flare. You can use manual focus or autofocus, which works silently and quickly thanks to a fast CPU.