My experience with this lens is based on more than 10 years of hobby photography. It is still on every one of my photo tours. Why? I will explain that to you in this experience report.
The lens is not necessarily super fast. The aperture can be set to a maximum of f/4. If you want to photograph your wife hand-held while bathing at night, there will probably be a significant loss of quality. The lens is only of limited use in poor light conditions without a tripod. Especially when the motif is moving, e.g. a flower in the wind, waves on the water or my wife bathing at night.
However, the EF 17-40mm is always used for landscape photography. Poor lighting conditions in particular make for dramatic shots. If you put your camera with this lens on a tripod and increase the exposure time, the insensitivity of the lens to light no longer plays a role. On the contrary, the less open aperture in particular ensures a very good depth of field. The optimum value for this lens is between f/11 and f/13.
The 500g heavy part is very robust and has everything a hobby photographer needs. The focus can be set to AF or MF and the image stabilizer can also be used to help. The filter thread has a diameter of 77mm. As a landscape photographer, the wide angle is particularly useful. With the smallest focal length of 17mm you get a lot of information on the photos. The small errors in the ultra wide angle, such as slight vignetting, some blurring towards the edge or chromatic aberrations, can be quickly corrected during image development.
These sample images are the finished results made with this lens.
The EF 17-40mm f/4 USM is an affordable alternative to the newer wide-angle lenses. With proper use, the results are indistinguishable from those obtained with more expensive lenses.