If you recently acquired your first interchangeable lens camera, you’re probably already thinking about what lenses to add to your bag. As cool as your new DSLR or mirrorless camera is now, it won’t reach its true potential until you take a deep dive into the world of lenses. It’s a somewhat sad fact that most interchangeable-lens camera buyers never take off the kit lens that came with the camera, which sort of defeats the purpose of having an interchangeable-lens camera. Chances are, investing in a new lens will offer a bigger boost to image quality than upgrading your camera itself, although if you are in the market for a camera, check out our digital camera buying guide.
Before we get started, you may want to brush up on the concept of crop factor, as lenses look different depending on the size of your camera’s sensor.
It’s about more than zoom
When you buy an interchangeable lens camera, you’re entering a relationship with that specific brand and the lenses available for it. For example, Nikon and Canon DSLRs use incompatible lens mounts. While sometimes two or more companies will share a mount (such as Panasonic and Olympus with Micro Four Thirds, or Panasonic, Leica, and Sigma with the L mount), you can’t just mix and match any lens to any camera.
DSLRs and mirrorless cameras — particularly entry-level models — are often sold in kits, meaning they are typically supplied with a basic zoom lens, which may be something like an 18-55mm or 14-42mm depending on the brand and format of your camera. One common misconception about interchangeable-lens cameras is that they offer inherently better zoom capability than a compact camera. In fact, the opposite is often true. An 18-55mm lens is only a 3x zoom. Compared to a compact camera like the $400 Canon PowerShot SX730 HS with a 40x zoom or the Nikon P1000 with a 125x zoom, this is nothing.
Typically, the maximum zoom power you’ll find in an interchangeable lens is around 10x, but comparing a DSLR or mirrorless camera to a point-and-shoot isn’t really fair. Interchangeable lens cameras use much larger sensors that produce very high-quality images compared to compact models, but those large sensors require equivalently larger lenses. This is why small cameras can have oodles of zoom, while larger cameras require on multiple lenses to cover the same range.
Zoom is also commonly confused with how close a lens can bring a subject. The zoom number, like 3x, only shows the range from the widest to narrowest angle of view for that lens. Zoom is a good indicator of flexibility, then, but not how close you can get with that lens. For that, you need the focal length, like 50mm, 100mm, etc. In point-and-shoot cameras, it’s more common for manufacturers to advertise the zoom rating of a lens (10x, 40x, etc.), whereas DSLR and mirrorless lenses will be advertised by their focal length range (18-55mm, 24-120mm, etc.). If a lens has a single focal length number, e.g. 50mm, it is a prime lens and doesn’t zoom at all, but generally offers superior sharpness, depth of field control, and light-gathering ability.
Wide-angle to telephoto: What is focal length?
Focal length indirectly indicates the angle of view of a lens. A wide-angle lens may have a focal length of 18 or 24mm, while a telephoto lens may be 100mm, 200mm, 400mm etc. On a full-frame camera, the switch from wide-angle to telephoto happens around the 50mm mark, with lenses near 50mm being referred to as “normal” focal lengths. Here are some various lens categories based on full-frame equivalent focal length (again, see our explainer on crop factor for an understanding of different formats and how they relate to full frame).
- Fish-eye lenses are typically wider than 14mm (although something this wide is not necessarily a fisheye)
- Wide angle lenses typically cover between 14-35mm
- Standard, or normal, lenses sit around 50mm, give or take
- Telephoto lenses cover between 70-200mm
- Super telephoto lenses start around 300mm
- Macro lenses come in multiple focal lengths, but allow you to get up close to the subject for extreme detail
Wide-angle lenses are often used for landscapes or working in tight quarters, while telephotos are popular for wildlife and sports. Portrait lenses generally fall in the short telephoto range, from 50mm to 105mm, although they can be longer. While shooting portraits with a wide-angle lens can be done, such lenses tend to cause distortion. This is why your nose always looks bigger in smartphone selfies, since phones have wide-angle lenses, but this can also help emphasize distance, which is why wide-angle lenses are popular for sports like skateboarding.
While a macro lens is most often a telephoto, what’s actually important here is the magnification, or reproduction, ratio. A typical macro lens will have a reproduction ratio of 1:1, which means if you photograph, say, a coin, the image of the coin projected by the lens onto the sensor will be the exact same size as the coin itself. You can imagine, then, how much detail will be visible when you look at that image on your computer screen or make a large print.
The convenience of a zoom lens can’t be beat, as it offers a wide range of focal lengths, where a prime lens is fixed at just one. Beyond the basic 3x kit zooms there are 7x and 12x lenses, often called “superzooms,” that are very popular. You’ll see figures like 18-200mm or 28-300mm. Other lenses are made to pick up where your kit lens leaves off, like a 55-210mm, and so on. Keep in mind, “zoom” does not mean “telephoto.” You can have wide-angle zooms which spend their entire focal length range well short of the 50mm cut-off point, such as the Sigma 14-24mm f/2.8 zoom pictured above.
The trade-off with zooms, particularly high-powered zooms that cover a long range, is that they generally aren’t as sharp or as bright as primes. Professional zoom lenses are quite good, but often offer less than 3x of zoom power and are considerably more expensive than kit zooms or prime lenses.
There are loads of zoom options; just check the manufacturer’s website for details and prices. If you just want more reach than your kit lens, something like a 55-200mm or 55-300mm (depending on what’s offered for your camera) is an affordable way to do that. And don’t be afraid to venture beyond the brand name on the front of your camera. There are third-party brands available — like Sigma, Tamron, and Tokina — that offer a variety of options, often with better price/performance ratios than first-party lenses.
Prime lenses — or more specifically, fixed focal length lenses — offer just one field of view. Prime lenses are some of the best lenses you can get for the money, and in most cases offer better image quality and low light performance than their zoom counterparts. A 50mm f/1.8, seen above, is perhaps the quintessential prime lens, offering a normal focal length a bright aperture. In particular, this focal length is a popular recommendation for photographers looking to move beyond their kit lenses, thanks to the relatively low cost and fantastic image quality and low light performance.
There are also many specialty lenses that are more common in prime form, like macro and fisheye lenses. Portrait lenses and many super-telephoto lenses are also offered as primes. Prime lenses typically come with larger apertures (denoted by the f-number, like f/1.8) that let in more light and allow for more background blur, which is nice for shooting portraits (see our depth of field explainer for more information on controlling blur). With your standard kit zoom, you’ll have to start using the flash in instances where you can still work with available light when using a fast prime lens.
Another reason to go with a prime is size. Especially with smaller mirrorless cameras, “pancake” lenses are very popular, which are ultra low-profile primes that you can take with you anywhere.
Why wide (or fast) apertures matter
As you start searching for lenses, you may do several double-takes when you look at prices. You may see one 50mm for $120 and another for $1,600 from the same manufacturer. With both primes and zooms, there are many factors that can make one lens of the same focal length more expensive than another, but the key difference is the aperture (or how wide the lens can open). This is measured in f-stops, and in what seems counterintuitive, the lower the f-number, the more light you can capture.
In the case of Canon’s $120 50mm lens, the maximum aperture is f/1.8. Canon’s $1,600 50mm features a brighter, f/1.2 aperture. The latter also uses higher-quality glass and construction, leading to the huge price difference.
All but the most demanding professionals won’t need an f/1.2 lens, but if you do a lot of shooting in low light without a flash, investing in a lens with a wide aperture, maybe in the f/1.8 to f/2 range, is certainly worthwhile. (Just for fun, we’ll point out that one of the fastest lenses around is thelens rated at f/0.95 — which costs a cool $11,295.)
For comparison, most kit zoom lenses have apertures no wider than f/3.5, and almost always the effective aperture decreases as you zoom. This is why you’ll see a lens name written as something like 18-55mm f/3.5-5.6. That implies that at 18mm, the widest aperture is f/3.5, while at 55mm, the widest is f/5.6 (which is about a stop-and-half slower, meaning it lets in less than half the light at 55mm as it does at 18mm). A prime lens with a large aperture often lets in two, three, four or more times the amount of light as a kit lens.
Professional zoom lenses typically max out at f/2.8, and are specially engineered to maintain that aperture throughout the zoom range. Something like a 24-70mm f/2.8 is a very popular lens made by many manufacturers, but such models can cost well over $2,000.
Many mirrorless cameras have image stabilization built into the body to help eliminate camera shake. However, this feature is much rarer in DSLRs. If you want stabilization on a camera that doesn’t have it built in, you have to buy a stabilized lens. Manufacturers use various tags to denote this feature, from Canon’s IS (Image Stabilization) to Nikon’s VR (Vibration Reduction) to Sony’s OSS (Optical Steady Shot).
Stabilization isn’t always necessary for still photography — shooting at a fast shutter speed will also keep things nice and sharp. However, when working in low light at slow shutter speeds, shooting video in any conditions, or using a very long focal length, stabilization is very important. Stabilization is more common on zoom lenses, less so on primes where the wider apertures let you shoot faster shutter speeds.
What’s the best lens to buy?
The best lens to add to your kit depends on what you want to shoot. A 50mm f/1.8 is an affordable, bright lens that’s great for low-light photos, portraits, or snapping better pictures of your pets. For landscape and travel, a wide angle lens might be in order, while telephotos are excellent for bringing wildlife and athletes up close. For more information, you can peruse our various lens reviews or read our guides on the best lenses for Nikon, best lenses for Canon, the best Micro Four Thirds lenses, and the best portrait lenses.
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