Canon EF 17-40mm f/4L USM

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Zoom lens

A zoom lens by Canon for Full frame cameras, 17-40mm f/4. An older, light L wide zoom that is plentiful used.

Maker	Canon
Focal length	17-40mm (zoom)
Maximum aperture	f/4
Made for	Full frame sensors
Mounts	Canon EF
Stabilised	no
Autofocus	yes

What it frames like

Its full-frame-equivalent focal length on the sensor it was made for.

How wide 17mm sees at its wide end on each sensor it covers.

f/4 wide open, to scale against f/1.4.

On full frame (Canon EF): as marked, 17-40mm.
On APS-C (Canon) (Canon EF): like 27-64mm on full frame; f/4 gives about the depth of field of f/6.4 there.