How To Buy a Lens For a DSLR Camera

Most people buy their first DSLR with a kit lens, which is usually the 18-55mm zoom. While it’s perfectly fine to start with, you will soon see that there is so much more to explore in the photography world, and that your camera is hardly the reason for amazing images (lenses are much higher on the list).

While there’s nothing wrong with using only one lens forever, it’s not what DSLRs were designed for. In order to get the most out of your camera in any situation, you should spend some time researching lenses and what all those different numbers and terms stand for. It’s all pretty simple understand, and this article I’m going to assume you have little to no knowledge!

Focal Length

Focal length determines “how far” the lens sees, and we have 3 different categories.

• Wide Angle Lens – Under 35mm
• Standard Lens – From 35 to 85mm
• Telephoto Lens – Above 85mm

Wide Angle Lenses

16mm

These types of lenses are excellent for any situation where you need to capture as much as possible in your scene (landscape, clubs, architecture, day-to-day stuff). A great example would be the Canon EF-S 10-22mm f/3.5-4.5 USM, and it can zoom all from 10 to 22mm. We also have fish-eye lenses, but those are extremely wide and usually below 10mm.

Standard/Normal Lenses

50mm

As you can tell by the name, standard lenses are used for daily activities, but can actually be used for pretty much anything if required (even wide or telephoto work). Their focal length is the closest to what our eyes see, and they’re excellent for the following types of photography; night life, concerts, traveling, cities, all around, kids, animals, you name it.

The Nikon 35mm f/1.8G is one of the most popular (also highly affordable) lenses because of its focal length, and great low light performance because of its large aperture opening.

Telephoto Lenses

300mm

For sports, action and wildlife, telephoto lenses are simply the best. At certain sports matches, you can’t always be close to your subject, and when shooting animals, it’s often dangerous to get too close to them. Telephoto lenses start above 85mm, but the real deal is around 300mm and longer.

These types of lenses can also get pretty expensive, especially if you plan on buying ones with large apertures (more on that later). For example, the Canon EF-S 55-250mm f/4.5-5.6 would be in the hundreds, whereas Canon EF 300mm f/2.8 starts at $7,000. You don’t really need the most expensive lens, especially if you don’t earn from photography yet.

Prime and Zoom Lenses

You’re probably used to lenses that can zoom, but in the DSLR world, there are plenty of lenses that have no zoom at all; we call them primes.

• Zoom Lenses – Can go from focal length to another by twisting the lens (10-22mm, 18-135mm etc.)
• Prime Lenses – Always at one focal length (35mm, 50mm, 105mm etc.)

Prime Lenses

Prime lenses have only one focal length, meaning there’s no zoom. The lens pictured above is a Canon EF 50mm f/1.8 II, and its focal length is constantly at 50mm. As a beginner you may think it makes no sense to limit yourself like that when a zoom lens can cover much more for the same price, but there’s a lot of terms that affect the image quality.

• Primes contain less elements (no need for anything to move), and their image quality is often much better.
• Their maximum aperture can be much bigger, usually from f/1.4 to f/2.0, and they can capture much more light (better for low light and blurring the background)

Zoom Lenses

Zoom lenses are excellent for situations where you don’t know what exactly you’re going to photograph, or when you just want the freedom of carrying around less gear, while still having great image quality. The Nikon 18-140mm f/3.5-5.6 above covers a range that 99% of photographers, especially hobby ones, will use on a day to day basis.

• No need to switch between lenses, just zoom from 24 to 70mm in a second, instead of changing lenses
• Less weight to carry around
• Less chances of getting dust/dirt on your sensor

None of these two types of lenses is better than the other, they both have their own advantages. Most people start out with a kit zoom lens and then see what they need, and a large majority of them have both primes and zooms in their bag!

Aperture Size

Besides focal length, the aperture size is one of the most important factors for lens’ performance and total price. You can read the full aperture tutorial here.

Fixed/Constant Aperture

Typically found on more expensive, and always on prime lenses, a fixed aperture stays the same no matter what focal length you zoom in/out to. Here are two examples:

• Canon EF 50mm f/1.4 USM – Prime lenses typically have very large aperture openings, and f/1.4 is excellent for low light, portraits and blurring the background

• Canon EF 70-200mm f/2.8 IS USM – Expensive zoom lenses tend to offer large apertures as well. From 70 to 200mm, the maximum aperture always stays at f/2.8

Variable Aperture

The value of aperture on these lenses changes as you zoom. It would be cool to have a large, fixed aperture all the time, but there are also physical limitations that determine how big a lens can be.

• Nikon 55-200mm f/4-5.6G ED IF – At 55mm, the largest you can choose is f/4. At 200mm the maximum aperture gets smaller for 1 f-stop (to f/5.6), which is a lot smaller than the 50mm above, but still great for outdoors and even indoors when you raise the ISO/choose a faster shutter speed.

Other Important Features

Focusing Motors – Lenses with dedicated focusing motors are faster, more accurate and more silent at auto focusing. Canon calls it Ultra Sonic Motor (Canon EF 85mm f/1.8 USM), Sigma Hyper Sonic Motor, and other brands have similar names as well.

Image Stabilization – Most images taken at night turn out blurry, and it’s because of a slow shutter speed. A lens with Image Stabilization will help you up to 4 stops (meaning 1/15 gives the same result as 1/250), but only for static objects (to freeze a moving subject, you need a fast shutter speed!).