Camera lenses are an expensive but mandatory component of high end photography. One way to get a good deal on a camera lens it to buy it used. Priceonomics can tell you a fair price that you can buy or sell used camera lenses for. To help us launch this guide, Priceonomics contributor Keith Thomson has put together camera lens buying guide. Read more below!

a close up of a camera lens

Image credit: Deviant Art.

A Buying Guide for Camera Lenses

So now you have your SLR camera body and need a lens to go with it. Without the lens, the camera is useless. It doesn’t work. It won’t record an image. Look through the VIEW-FINDER and you’ll see a white blur, or, if the cap is on you’ll see black. And be aware, we keep the cap on to prevent any debris, such dust and sand, or moisture from getting into the camera, which can cause damage to the electronics or mechanics, as well as on leave “artifacts” on an image. Camera bodies and lenses often need to be professionally cleaned and maintained, so the better you take care of your gear, the better it will function and the less maintenance it’ll require.

You will soon understand that the piece of gear in your collection that’ll you’ll forever be thinking about is the LENS, sometimes lovingly referred to as “the glass.”

Most camera bodies, when purchased new, can be bought as a “kit.” This means that the body comes with a lens. “Kit lenses” are most often basic, low- mid level quality zoom lenses, so, the more you learn about what a lens can do for your photography, the less desire able these lenses are. You’ll often find “kit lenses” for sale inexpensively in the second hand market.

What to keep in mind when buying a camera lens

If you’re looking to purchase a lens, you’ll find that a good lens can cost far more than you paid for the body, so there are the basic terms and functions that may help inform you:

LENS MOUNT: The ring around the big hole used to attach your lens to the camera. The most important thing to know when buying a lens is if it will fit your camera. Camera brands make lenses specifically for their cameras, thus maintaining their market. You generally can’t use a Nikon lens on a Canon camera and vice versa, but there are also THIRD PARTY MANUFACTURERS that make lenses with mounts for the different camera body manufacturers. These are usually less expensive, such as Tamron and Sigma, and can be of a lower quality, but definitely not always.

FOCAL LENGTH: This is the angle of view. This generally means how “far or close” you want to be from the subject you are photographing. 50mm is considered the STANDARD FOCAL LENGTH and is said to be the closest to the human eye, so it is also referred to as a NORMAL lens. Common WIDE ANGLE LENSES are in focal lengths of 24mm, 28mm, and 35mm, though there are others. These give a wider angle of view and the focus on objects that are closer. Common TELEPHOTO LENSES are in focal lengths of 75mm, 100mm, 135mm and 200mm though there are others, and give a narrower angle of view, focusing on objects that are farther away.

FIXED FOCAL LENGTH vs. ZOOM: A fixed focal length is sometimes called a PRIME LENS. To change what you see through the view-finder, means you have to get the camera (your body) closer to, or farther away from the subject you are photographing. A zoom lens has a FOCAL LENGTH RANGE, for example 28mm-105mm. This means you can have the camera in one place and with a twist of the lens ring change the angle of view, bringing the subject closer to, or farther from, you. You may think it would be common sense then to buy a zoom lens right? But without going into the details of professional photography, let’s just say that prime lenses are considered to produce higher quality images and usually cost more than your average zoom.

APERTURE: The size of the hole that allows in the light collected by the sensor. This also determines the LENS SPEED. When it’s at its’ widest open, it allows in more light, and the SHUTTER SPEED can be set faster. A smaller, less open aperture, has a narrower, more condensed stream of light. If the aperture is less open, and you were taking the same picture, you would want to set a slower shutter speed so that the sensor has more time to absorb the less light it is receiving, thus also giving more depth to the subject farther away; The wider possible aperture on a lens the better because you have the option of more light to work with. There are also FIXED APERTURES and VARIABLE APERTUREs. Again, without going into details and professional specifics, fixed is more desirable than a variable and therefore usually costs more.

F-STOP: Officially: The ratio between the diameter of the aperture and the focal length. Practically: How much light you’re allowing in through the aperture in numerical terms. It seems like an inverse relationship, but the lower number the f-stop, the wider the aperture, the more light is allowed in. The higher the f-stop, the less wide the aperture and the less light allowed in. A wide aperture, allowing in more light would be f1.4, a small aperture, allowing in far less light is f22. There is a symbiotic relationship between f-stop and the SHUTTER SPEED


There is much to learn about lenses and it can get very detailed and specific. As always, where ever you are with photography, before considering a purchase, ask yourself what your purpose of the lens is. Is it a lens just for portraits? A “walk around lens?” Do you want to photograph birds or mountains or things I the distance? There are many websites that compare lenses with test examples and opinions of the tester. A cheap “kit” zoom lens can cost $300, while a “pro” fixed lens can cost $1500. There is also a very large market for used lenses, and because of their high demand, the prices stay pretty steady. There are also adapters and techniques etc. that allow you to use different lenses on different camera mounts, so with a lot of research and understanding, you can put together a good, cost effective lens collection. That’s a whole other article though. I’m sure you’ve enough to digest all ready.