The difference between zoom and prime lenses

A lot of people have a camera, be it in their phone, a compact camera, a dSLR or any other type. Most of these cameras, especially the compact cameras, have zoom lenses. All the bigger cameras (dSLR, ILC etc) are also often shipped with a kit lens which zooms. If you start shopping for new lenses later because you notice you can’t zoom enough in either the wide or the tele part you might just go for another zoom because that’s what you’re used to. But there is also another type of lens, the lens with a fixed focal length.

What does this mean? It means that the lens doesn’t zoom anymore, so to get an object closer by or further away you need to walk to or from the subject. This means that you have to walk to “zoom”, which is why this is also referred to as “sneaker zoom”. So, that’s the downside. Then there surely must be an upside to it, right? Yes there is. Actually, there are most likely two upsides, namely:

  • Faster lens (higher aperture)
  • Better optical quality

Faster lens

Because there is only one focal length that the designers have to take into account, they can optimize the lens for light. Where your typical zoom lens starts at F/3.5 a prime lens starts at F/2.8 or even F/1.8. There are even a few industrial lenses which go as far as F/0.75 which mean they really catch a lot of light. The advantage of this is that you can go into much darker situations without using a flash or bumping up your ISO value to the point where you get grain. And be honest, no-one likes grain in their photos.

Better optical quality

This is also a design point, because you have only one focal length, you don’t need to make sure that the lens works for everything from 18 to 105mm (the range of my kit zoom). This means you get a lot less distortion, be it barrel or pincushion, which also contributes to a better picture.

I’ve been shooting with prime lenses for a while now, and especially for things like concerts and other events in theaters I really prefer prime lenses. I occasionally use a zoom lens, but that’s mostly because of the filters I have for that. For example my kit zoom which has a nice polarizer filter for true blue skies. But I most often have a 35mm or 50mm prime on my camera.