What’s the Difference Between a Zoom Lens & a Prime Lens?

I’ve been working with cameras and lenses for quite a few years now and to this day, I still have a battle raging inside of me. Which is better, a zoom lens or a prime lens? And what’s worse, as I sit here and type, I can’t give you a definitive answer. Both options are really good and both options serve their own purposes. I guess it boils down to what you need your lens for and what you plan on shooting.

In today’s post, I’d like to cover a few things. First, I’ll explain the difference between prime and zoom lenses and then after that, I’ll offer up some opinions on what each type of lens is good for. By default, if one lens is good for one thing, the other isn’t as good, so I won’t even bother telling you what each lens isn’t good at. Well, maybe I’ll touch on that a little bit, but I won’t dwell on it.

The purpose of this post is to give an initiation of sorts to newer, less experienced photographers or individuals who may just be entering the industry now. I can remember back when I first began learning about lenses and I recall the feeling of being overwhelmed. It’s easy to become overwhelmed at that stage and the sheer number of opinions coming from each and every direction makes things downright unenjoyable. My goal today is to help you make a decision when it comes to lens choice. Many people simply have no idea why they’re using what they are and it’s my hope to clarify a few things.

Prime Lenses Versus Zoom Lenses

Okay, here’s the deal. A prime lens is a lens that has a fixed focal length and a zoom lens is a lens that has a variable focal length. This length I’m referring to here is generally referred to in millimeters (mm). This is the “mm” in the statements you here out there, such as, “I’m picking up a sweet 50mm prime lens tomorrow.” Or, “My friend tells me his 50-300mm zoom lens is the best he’s ever owned.” Lots of beginning photographers haven’t yet learned what the mm that’s written on the side or front of a lens means, so I hope this helps.

So what is focal length and how does it differ between these two lenses? Well, focal length certainly isn’t how long the physical lens is. That’s what many folks think and it’s not true. What focal length is, is the distance from the sensor of the camera to the point in the lens where light rays converge to create a sharp image. So basically, is simple terms, the “mm” that’s written on a lens means that the distance from a certain point in a lens to the actual sensor in the camera is a set value. This value can either be fixed, as in a prime lens or change, as in a zoom lens.

If you’ve ever used a camera before that had a zoom lens attached to it, you may have noticed something very interesting happen as you zoomed in and out. As you zoom in, the, what’s called the “angle of view” gets narrower and narrower. Objects in the scene also become larger and larger, or as what’s referred to in the camera world, “magnified.” These characteristics are true for longer focal lengths. So if you compared a 50mm lens to a 300mm lens, the 300mm lens would have a much narrower angle of view and the objects that are seen through the lens would be rather large and magnified. Conversely, the 50mm lens would have a much less magnified view and you’d see a lot more of the scene. The angle of view would be much wider.

What’s So Great About a Zoom Lens?

I’ll admit, I use a zoom lens. I’ve tried many in my day and I’ve settled on the Canon EF-S 18-135mm f/3.5-5.6 IS STM lens. I’m sure I’ll pick up another type of zoom with different characteristics one day, but I get so much versatility with this one, it’s difficult to imaging why I would do this. Most likely, I’ll buy something larger and more powerful.

The reason I use my zoom lens is simple; it can do almost anything. I can take fairly wide shots and I can zoom in and magnify something so it appears very up close. Since I do a lot of outdoor photography, this versatility is important. I don’t like changing lenses too much because it’s sort of a pain and dust and dirt can make its way into the camera every time the lens is removed (especially outdoors), so I like to keep that to a minimum. But really, it’s the zooming I like. Even for the same subject, I’ll take some wide shots of it as well as some close up ones. And I don’t even have to move or change position while I’m doing that. Inventing the zoom lens was a wonderful thing.

There are a few issues with zoom lenses though. They can be quite large and cumbersome at times. They have lots of moving parts that can malfunction, flat out break or not work as well as you’d expect them to. For instance, on my Canon zoom, the lens tends to zoom itself in when I don’t want it to during photo shoots where I’m facing the ground from up above. This is called lens creep or zoom creep and it’s so annoying. The lens barrel basically extends itself due to its own weight.

Zoom lenses are versatile though. You have to give them that. They’re great for landscape and portrait shots and all you need is one lens most of the time. This is another problem with them though. They tend to make the photographer somewhat lazy. Sure, I’ll admit that photographers look really cool when they’re operating those big lenses, but when was the last time you saw a photographer moving around the scene, trying to get the best shot, with a zoom lens? They do that, but not as much as they would if they were using a prime lens. You can pretty much sit down in one spot all night and take all different types of photos with a zoom. I’m not sure how creative those photos would be though.

What’s So Great About a Prime Lens?

Prime lenses don’t zoom. You are the zoom. If you want to take a shot that’s closer up to the subject, you have to walk nearer to that subject. This is quite the surprise to many people after they’ve gotten used to using a zoom lens. I’ve seen friends use a prime lens for the very first time after using a zoom lens for years and instinctively go to twist the lens barrel. Of course, there was no twisting to be had. The lens didn’t zoom.

Prime lenses have not nearly as much versatility as zoom lenses do. If this is the case, it begs the question, why on earth would anyone use a prime lens? There are actually many reasons, which I’ll explain below.

Let me make a comparison before I go into my explaining though. Picture owning a really nice and sporty BMW car. If you aren’t aware, BMWs handle the road like they’re on rails. They’re stable and firm and you can take corners like it’s nobody’s business. Try driving a BMW and you’ll see what I’m talking about. A corner that a Honda Accord can handle at 40mph, the BMW can handle at 100mph. It’s an incredible feeling.

Imagine being at the car dealer as you’re purchasing the BMW. The salesman asks you what type of tires you’d like on the car. He says, “Well, the big “all-purpose” tires can deal with so many situations. They’re good in the snow, they’re fine on sand, they’re comfortable because they’re so large (they can absorb any bump in the road) and you won’t even notice you’re traveling in the car because they’re quiet.” You’re thinking, “Wow, I really want those all-purpose tires. They sound great for so many situations.” Since you’re curious though, you ask about the other option. “Well,” says the salesman. “The other option is a more streamlined tire. It’s thin and firm and it’s not a good snow tire. With these tires, you’ll feel every bump in the road and they’re sort of loud. You will, however, have the ability to handle corners at twice the speed of the all-purpose tires and the overall speed rating increases dramatically with these tires as well.”

So, which type of tire would you choose? The “all-purpose” tires or the “sport” tires. By the way, the all-purpose tires are comparable to the zoom lens and the sport tires are comparable to the prime lens. Many people like the sport tires because they want the feeling of the road. Much like prime lenses that force you to move around your subject for the most creative types of shots. Like sport tires’ handling abilities, prime lenses have apertures that can open up very wide (f/1.4 to f/2.8), which is great for low light situations (performance). They’re also extremely clear. They’re small, compact and light. They’re easy to carry around.

Large apertures are great for creativity and performance because they can handle low light situations much more elegantly than zoom lenses with smaller maximum aperture sizes can. With a larger aperture, you can use a faster shutter speed with a lower ISO setting. This means that you’ll have less grain in your photos and less camera shake or blur. Also, you can achieve a wonderfully shallow depth of field and a very pretty bokeh with a large aperture setting, so this is a definite consideration when deciding on what type of lens you’d like to purchase. Personally, I like large apertures for the amount of light the let in. That’s a huge selling point.

In the past, it was considered common knowledge that prime lenses took higher quality photos when compared to zoom lenses. The reason for this was because the prime lens contained fewer lens elements inside the lens barrel. The lenses were simpler and because of their “single focal point” optimization; their resulting photos were visibly sharper than their zoom counterparts.

It’s my understanding that these differences have been minimized over the past few years. Lens manufacturers have reduced any quality discrepancies between corner to corner sharpness and many zoom lenses today are comparable to many prime lenses at equivalent focal lengths. And in some cases, the zoom lens outperforms the prime lens, so this is something you should surely look into, if this is a consideration.

Overall, my advice is to own at least one great zoom lens and one great prime lens. As I told you above, I still can’t decide which is better, but I can’t imagine life without my zoom. I do want to pick up a high quality 35mm prime though. Perhaps I should start looking into that.

If you have any questions regarding this post, please don’t hesitate to leave them for me in the comment section below. Thanks for reading!