1 Quality Advantages of a Prime Lens
The Prime lens has a huge advantage for the autofocus motor in a way, that it doesn’t have to adjust for different focal lengths. Zoom lenses are designed to move, which restricts the ability to optimize for a fast auto-focus.
Zone-Focusing is also a lot easier when you only have to adapt to one fixed focal length. Instead of adjusting the focus distance for every focal length individually, you only have to focus once and keep the setting for the rest of your walk.
The auto-focus already showed that it is a lot easier to manufacture a prime lens than a zoom lens. Therefore, a prime lens in the same price range as the zoom lens will always be better in image quality.
2 The Benefits of a Fixed Frame
The fixed focal length means that every time you look through the viewfinder you have the same frame and point of view. With zoom lenses, the frame and especially the angle depends on the focal length.
If you are photographing on the wider end of your zoom lens, not only will the distance vary, but also the distortion of the image.
Having a fixed frame is also advantageous for shooting from the hip. After a while, you are so familiar with your prime lens that you don’t even have to look through the viewfinder to know how the image will look like. This muscle memory will help you when you shoot from the hip and have to guess the frame intuitively.
3 Forced to move with a Prime Lens
Zoom lenses can make you a lazy photographer. You know the whole “If your pictures aren’t good enough, you aren’t close enough” paradigm, hasn’t much to do with zooming in on the subject but getting closer physically?
The problem with a zoom lens is, that instead of moving and getting closer, you will simply choose the long range of your zoom lens. Hence, your images will look very disconnected from the subject and be pretty emotionless.
Instead, get closer with your feet, force some reactions and fill the frame with emotions. It will show in your images if you got physically closer, or if you shot from far away.
4 More Compactness
Weight and size should definitely be factored in when buying a lens for Street Photography. You will be on the street for hours and a few 100 gram can already make a big difference for your neck or work in general.
Due to their design prime lenses are lighter and smaller than their zoom counterparts making them more suitable for Street Photography. Not only is it less straining for the body, but the smaller size also less intimidating.
For Street Photography the appearance is important since we don’t want to look like the professional Paparazzi out on the hunt. Rather we want to appear like the friendly tourist having a good time. A smaller lens looks less professional having a positive psychological impact when shooting on the street.
5 Higher F-Stop
Prime lenses also offer a more open aperture due to their design advantages. Where zoom lenses struggle to reach the f/2 stop, there are high-quality primes lenses easily going as far as f/1.4 or f/1.2 for a reasonable price.
Yes, there are even lenses out there that reach f/1.0 or beyond, but they mitigate the advantages of a prime lens by being too heavy and big. Therefore I wouldn’t them consider well suited Street Photography lenses.
The wider aperture might not make much of a difference during the daytime, but at night, having the advantage of using a far lower ISO reduces the distracting digital noise heavily.
6 Concentrate on Composition
With every feature and gimmick that comes with your camera gear, lies the risk that you get lost in it. The prime lens reduces your photography to the basis and you aren’t even dared to spend time zooming in and out of a picture trying to improve it there.
If you are having problems to find the right distance through the viewfinder, a zoom lens won’t be your solution, but delay your progress.
Learn the art of photography and create the distance through compositional techniques like layering. Your images will benefit more from investing time in learning Street Photography and choosing the prime lens, then using the zoom ring.
7 Less Expensive
Prime lenses not only offer a wider aperture, or sharper images, they are also a lot less expensive than their zooming friends. Lenses like the Canon 50mm f/1.8 go for a bit over $100 but have a very high image standard.
If you are still unsure what focal length you prefer, you can probably buy two or three simple prime lenses for the price of one tele-lens, albeit offering better image quality and higher aperture. In case you just recently got your camera that came with a standard zoom kit lens, you can also try to not change the focal length for the whole walk.
It might feel a bit awkward in the beginning to restrict yourself, but soon you will find out how much more fun it is to not worry about the focal distance and simply be able to photograph.