What are the characteristics of a zoom lens?
A zoom lens has a wide range of focal lengths to choose from, is quite expensive, but is like having many lenses in your bag without the need of changing them every time you need a different focal length. The focal ratio usually is higher than a prime lens, for example the Canon 16-35mm USM has a focal ratio of 2.8 and is really expensive, but you can find prime lenses with focal ration of 1.2. A zoom lens is usually bigger than a prime lens.
What are the characteristics of a prime lens?
A prime lens has one and only one focal length, they are cheaper than zoom lenses, some high quality lenses have really low focal ratio, for example the Canon EF 50mm f/1.2, they are usually more compact than zoom lenses, also thanks to the lower focal ratio you can make amazing bokeh shots.
So should I go for a zoom lens or prime lens?
With a zoom lens you can reduce drastically the number of lenses you need to carry with you, also you can use your time making good content instead of wasting it changing lenses over and over again, with a zoom lens you have more options when you shot, wherever you are, you are able to change the zoom level of your lens and still be able to frame your subject correctly.
With a prime lens you need to worry much more about where you are in relation to your subject, and most of the time, you might wish a different focal length for that situation. If you are starting making videos with digital cameras I recommend zoom lenses, most of the time you don’t need a focal ratio of 1.4, not even 2, that you find on prime lenses, the focal ratio of good zoom lenses is perfectly fine and you can still achieve beautiful bokeh shots it you want.
With a prime lens you need to move more in order to have your subject always in the frame, and this is not a bad thing, you can discover better locations and angles for making your frame looks better, also keeping a low focal length make the audience feel like they are in that place with the subject, instead with a zoom lens you can stay in one place and be able to shot many subjects, but than, you need to use a large focal length at some point, and the feeling that you give to the audience will change, as if the audience is looking at the subject from far away.
I highly suggest a good zoom lens, usually in the range 16-50mm, without going too high, if you have an high budget, I prefer wide angle lenses, and keeping a low focal length also help for stabilization, when you start going over 50mm you will have issue trying to stabilize your video. The image stabilization help a lot when doing videos, for example the Canon Ultra-wide zoom 16-35mm f/4, or the kit lens in most Canon cameras has image stabilization. It seems that this feature comes at the cost of a more high focal ratio so it is up to you to decide if giving more importance to the stabilization of the image or to a more shallow focus for beautiful bokeh. Prime lenses are a good option if you can’t afford a zoom lens and also are more challenging since you need to think how to have the best shot with one focal length.
In the overall there is no winner, both lens are good, I suggest to look for used lenses since they will be much cheaper, and in the future you will be able to resell them almost at the same price you purchased them.
What is a Bokeh?