Buying a prime lens could just be the best investment in camera gear you can make.

In 5 Things I Wish I Had Known Before a DSLR, I talked about the value of good quality lenses. In conversations with people afterward, I’ve had a lot of people ask me why I consider a prime lens to be such an essential purchase. Here are 5 reasons why I think every photographer should have at least one prime lens in their camera bag.

Image Quality

A prime lens is one where the focal length (zoom) is fixed. This means that you can’t zoom the lens in or out. While this may seem like you’re losing out, you gain immensely in image quality. There are very few lenses that can produce a consistently high image quality across their full zoom range. Almost all of them will give you some distortion at both the high and the low end of the range.  Unless you’re willing to spend thousands of dollars on a single lens, there’s usually only a very small range where the image will be tack sharp.

A prime lens doesn’t have this problem. Having only one focal length, it is designed in the factory to be sharp. Unless you’re buying a really cheap knockoff brand prime lens, they can almost always produce a sharper image than a similarly priced (or even more expensive) zoom lens.

Higher aperture range

Prime lenses, because they don’t have to deal with a wide range of focal lengths usually offer a much wider maximum aperture than their zoom lens equivalents. If you bought your DSLR with a kit lens, it’s more than likely an 18-55mm lens with an aperture range of f3.5 to f5.6. At 50mm your maximum aperture is probably close to f5.6. The least expensive prime lens that most manufacturers make is a 50mm f1.8. For the technically inclined reader, this means it gives you more than 4 stops more.

Why does the wider aperture matter? There are two primary cases in which it makes a difference. First, being able to open the lens wider allows more light in. This means that you can shoot faster in lower light. Most concert and event photographers I know swear by primes for exactly this reason. It’s hard to shoot a concert when you have to choose between blurry images or grain from high ISO.

Second, if you’re looking to get the blurred background look, having a wider aperture will help to push the background out of focus. You can see in the images below how much of an impact going from f5.6 to f1.8 can have on an image.

Canon 18-55 zoom lens

This image was shot with an 18-55mm kit lens zoomed to 50mm. At the maximum aperture of f5.6, the background is still very visible.

50mm f.18 Prime Lens

Shot with a 50mm f1.8 prime lens. At f1.8, the background is now much more blurry and the difference in focus on the dragon’s head creates more of a mood than was possible in the first image.

Creative expression

When you can’t zoom the lens to get closer to the subject you have to move yourself. This alone can really push you to find more creative angles to shoot from. It forces you to rethink your composition. Moving around helps you to see things from a different perspective, and, sometimes, to see things you hadn’t noticed before. I don’t always understand why but better shots seem to just pop into my head when I’m looking through a prime lens.


Size and Weight

Because prime lenses have fewer moving parts, fewer motors and fewer electronics, they tend to be smaller and lighter than zoom lenses. If you’re planning to shoot for a few hours on end, having less weight on the camera makes shooting more enjoyable.



When it comes to prime lenses, one of the absolute best manufacturers of good quality glass is Sigma. They make lenses for all of the major brands of DSLR and, in general, their lenses are significantly cheaper than the Canon or Nikon equivalent. In some cases, the cheaper Sigma lens is even better than the equivalent.


I’ve never understood why the cheapest Canon lens you can buy is a 50 mm f1.8 prime lens. Sure it’s mostly made of plastic but the image quality you can get from such a cheap lens is why photographers around the world call it the “plastic fantastic”.


In short, the value for money that you get from buying prime lens far outweighs any other purchase I can think of when it comes to improving your photography. If you don’t already own one, make your next lens purchase a prime lens.  If you live in Ottawa, I highly recommend Henry’s. If you’re looking to save a bit of money, you can buy very good quality used lenses from them too.