The Canon EF 17-40mm f / 4L USM is a very good choice if you need a wide angle.
The main feature of 17-40mm is focal length. Unlike 24-70mm, there is a really wide angle here. This lens is more specific because less suitable for reporting and working with people. His prerogative is photography of interiors, landscapes, travel.
By the way, I would boldly call this model versatile full frame travel zoom lens... It is small, lightweight and great for focusing on such a role.
For 5 years at my disposal Samyang 14mm f2.8 and about 15 years old Canon 24-70 f2.8L (first first version, later second). I can say that 17mm is very close to 14mm. If you do not deal with interiors, such a difference will not play a role and it is better to take a zoom of 17-40mm, because it is more functional.
For shooting interiors a combination of 14mm + 17-40mm is ideal. In all other directions, 17-40mm would be a more interesting choice.
For example, at weddings Canon EF 17-40mm f / 4L will perfectly replace the bunch of fixes 14mm + 35mm, which I wrote about in article on choosing optics for wedding photography.
An important point is an excellent full frame width, but a useless lens for Canon camera crop... For crop 1.6, you need to buy Canon 17-55mm f2.8 (as a standard) or Canon 10-18mm f4.5-5.6 STM (as shirik), but 17-40 f4L - neither here nor there.
The lightweight metal body offers the advantages of compactness and reliability. My second-hand copy was bought from a person who also bought it not new. Nevertheless, the condition is excellent.
The zoom ring rotates very easily, which cannot be said about the focus ring, which is hardly required in practice. the wide angle catches hares very well both in the sun and indoors.
It's sharp enough that you don't think about it. Yes, soapy spots can be found in the extreme corners. But in real conditions, the detail will not cause any complaints. If subjectively compared in terms of sharpness, then it is in the middle between the sharper Samyang 14mm f2.8 and the less sharp Canon 16-35 f2.8L of the first version. Again, working out the details here is not a problem.
The color reproduction is juicy and with high micro-contrast, as you would expect from an Elka. Naturally, the picture is generally darker than on lenses with an aperture of f2.8. But if you're not comparing photos side-by-side, this won't be a problem.
Slight distortion and vignetting are present. They are treated quickly and painlessly with profile correction.
Among Canon lenses with similar focal lengths, this model is ideal in terms of price / quality / size ratio.
Next I would consider the Canon 16-35 f4L IS. It's even sharper and more importantly has a stabilizer. A stabilizer for a landscape lens is more important because lets you shoot handheld where f2.8 won't help you.
If we talk about the Canon 16-35 f2.8L I, II, III line, I would look at the second version as more adequate in terms of price and quality. The first is very average in sharpness, and the third is exorbitantly expensive. As for me, at such focal lengths f2.8 is not a priority anyway.
There are tons of third party lenses in this focal length range. But no matter how much I look at them, they lose to my native Canon either in image quality or in price.
A small, inexpensive and yet very high quality lens is the Canon 17-40 f4L. Further, there will be compromises on certain parameters.
See more in my video review: