Obviously a piece of photography equipment will not make you a better photographer alone. You need to put in the effort, time and thought behind improving your eye and start to see better compositions and subjects.
But that said, when people ask me for a recommendation for a lens that will take their photography to the next level, I think they expect me to say some expensive zoom lens. On the contrary, I recommend the $550 Canon EOS 35mm F/2 or complimentary lens for Nikon or even a third-party 35mm lens.
Why do I recommend the Canon EOS 35mm F/2 ? Primarily (no pun intended) because it is a prime lens. Prime lenses have a fixed focal length. This forces the photographer to move their body into position to get the shot rather than lazily zooming in and out. As it is people using zoom lenses tend to zoom in too much and eliminate a lot of the information surrounding a subject that gives the image its story or context.
Press photographers and documentary photographers have always embraced the 35 mm focal length for it’s storytelling ability. Normal human vision is approximately 47 mm on a full frame camera, so the 35 mm is a wide lens, but not so wide that is gives a distorted image. Just wide enough to include some surrounding information.
This Canon EOS 35mm F/2 is also a lightweight lens and seems to perfectly balance the Canon 6D body. The lens is smaller than a big lens, so its less intimidating to the people whose direction you point it at.
It is also a relatively fast lens. At the point I added this lens to my lens collection, it was the fastest lens (widest aperature or lowest f number) I owned as most of my other lenses were f/4 lenses. What does this mean? Well as you can see in the photograph below, you can shoot at f/2 and get some beautiful out of focus areas and this lens is very sharp at f/2.
The sharp optics, built in image stabilization plus the wide focal length and the prime lens configuration all combine to create a lens that produces excellent, sharp images. This is an excellent lens for video and for low light photography.