So, you're thinking of getting a new lens, but you're not quite sure either to get a prime lens or a zoom lens. Both types of lenses have their benefits and drawbacks, and you want to make sure you make the right decision and get the lens which best fits your photographic needs.
In case you did not already know, the main difference between a zoom lens and prime lens is that a zoom lens allows you to adjust your focal length between a certain range (for example 18-50mm), whereas a prime lens has a fixed focal length.
So you may be wondering what the point is of using a prime lens. Surely if you have the choice between a lens with flexibility and one with no flexibility, then surely the flexible one is the best one, right? Well, it's not really as simple as that, because prime lenses do have a few advantages. To begin with, they are lighter than zoom lenses because they have less moving parts. Mechanically speaking, they are simpler.
In addition to this, prime lenses often have wider apertures. The aperture of a lens controls how much light the lens lets in at any one time. Aperture ratings are in ratios, for example 1: 3.5 or 1: 2.8, but usually when buying a lens you will see it stated without the 1 in front of it, for example 3.5. Lenses with lower aperture numbers are more expensive, as a lower number means a wider aperture. Having a wide aperture creates a shallow depth of field, meaning that only a small distance range is in focus. A narrow depth of field (a wide aperture) would be great for close-ups of flowers where you want the background blurred, whereas a large depth-of-field (a small aperture) would be ideal for landscape photos.
Okay, so how about the zoom lens?
Well, a zoom lens will give you a larger range of distinctions to frame your photo. This means that you do not need to walk closer or further away from your subject to get the picture you're after. It can also be great for taking pictures of wildlife, because you can zoom in without having to change your position, so you will be less likely to scare the animal off.
The best way to decide what type of lens is right for you is to ask yourself what type of photography you are going to be doing. If you are going to be photographing a scene which remains still, such as a landscape scene, then a prime lens could be a good choice. If on the other hand you want to photograph things that are moving, such as animals, people, or sports photography, then a zoom lens is essential.