What is a Prime Lens?

You might have heard recommendations that if you want the fastest and sharpest lenses you should use prime lenses. So what is a prime lens?

You might have heard recommendations that if you want the fastest and sharpest lenses you should use prime lenses. So what is a prime lens?

Simple: It’s a lens that doesn’t have a zoom. It has a fixed focal length, something like a 24mm, 50mm, or 400mm. If it includes a range, like 24-70mm or 100-300mm, it’s a zoom lens.

So Why Would I Want a Prime Lens?

While it’s not a hard and fast rule, there can be two main advantages to prime lenses: speed and sharpness.

Because they don’t have all the complexity and extra glass of a zoom lens, prime lenses can be a lot faster. The fastest commonly available professional zoom lens, like the Nikon 17-55mm or Nikon 70-200mm have a widest aperture of about f/2.8. Many other zoom lenses have a maximum aperture of around f/4 or f/5.6. But it’s common for prime lenses to go down to f/1.8, f/1.4, f/1.2, or even f/0.95. That means that they let a lot more light in, making them very good for low light situations.

Those large apertures also mean that they can be used to get a very low depth of field. So if you’re looking to blur the background of your shots with very narrow selective focus, a fast prime lens might well be the way to go.

Good prime lenses can be tack sharp, often sharper than zoom lenses.

And prime lenses in the 50mm to 135mm can make for excellent portrait lenses. The combination of a flattering focal length, being very sharp, and a narrow depth of field can be really useful in taking photos of people.

This shot of fishermen on the Galata Bridge in Istanbul is a good illustration of the narrow depth of field of the Nikon 85mm f1.4, with its moderate telephoto effect.

This shot was taken with a Nikon 24mm f/1.4G on a Nikon D800 and shows how the wide apertures, in this case f/1.4, can get very shallow depth of field even on wide-angle lenses.

So Why Wouldn’t I Want One

The downside is convenience and versatility. Without a zoom, it means you have to pay more attention to where you are in relation to the subject–if you want it to fill more of the frame, you have to move closer. Of course, that can be a good thing, making you think more carefully about each shot. But it’s not always convenient or possible.

Are They Expensive?

They can be, but they don’t have to be. Both Nikon and Canon have 50mm f/1.8 models in the $129 to $219 range. But you can also get faster versions: a 50mm f/1.4 is about $550 and a 50mm f/1.2 manual focus is $699.

You can also get some excellent prime telephoto lenses, all the way up to this 600mm f/4 monster that clocks in at over $10,000.

Some Go-To Prime Lenses Worth Trying

50mm f/1.8. One of the most popular and versatile prime lenses is a 50mm f/1.8. Back when the 35mm film size became the standard for SLRs, the 50mm focal length gave a close approximation of a “normal” field of view. And so the 50mm became the standard lens included by default with many cameras. If you want to get back to basics, stick a 50mm lens on the camera, leave all the zoom lenses at home, and just go shoot. It’s a great way to get the creative juices flowing. If your budget can support it, you can get a faster f/1.4, but often the f/1.8 is among the sharpest lenses made. And it’s often very reasonably priced.

85mm f/1.4. Nikon’s 85mm f/1.4 is another beautiful lens. It’s superb for candid portraits, especially on a camera with a DX sensor. The only catch is that it can be a little unforgiving, especially on a DX sensor. At f/1.4, the depth of field is very narrow, and the telephoto effect on a DX sensor means that in low light it can be tricky to hand-hold below 1/60 of a second.

24m f/1.4. Nikon’s 24mm f/1.4G is one of my all-time favorite lenses and the one I keep on my Nikon D800 most of the time. It works wonderfully in low light and is beautifully sharp. It does suffer from a bit of chromatic aberration wide open, but that’s easily fixed in Lightroom 4.

This shot with the 85mm f/1.4 wide open (ie. at f/1.4) takes advantage of both the very wide aperture for low light and the narrow depth of field.

There are plenty of other prime lenses, including some excellent wide-angle and specialized lenses. And a good option if you want to take some for a spin is to rent one from somewhere like LensProtoGo.com, which is a great way to try out lenses you’re considering buying or lenses you could never realistically afford (like this $10,000 600mm f/4 beauty).

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