Your DSLR likely came with an 18-55mm or 18-135mm zoom lens. Supplementing or upgrading that lens to a higher quality zoom or a fixed-focal-length lens that captures more light can really improve the quality of shots that your camera is capable of. There are a few different approaches you can take when choosing a lens for your camera, and some limitations to consider.
We've highlighted some of the best zoom and prime lenses that we've reviewed here, with the scope limited to third-party lenses that are available for multiple camera systems—if you already have a Canon, Nikon, or Pentax you can check out a list that's focused on each mount.
Some are general purpose zooms—you can choose to supplement your kit lens with one that has a longer focal length for telephoto shots, or to replace it with a lens of higher quality that covers about the same range. We've also listed a selection of fixed-focal-length lenses for shooters who prefer primes, an excellent macro lens for close-up photography, and a fun special effect lens.
If you're new to the world of interchangeable lens cameras, it's important to know that lenses are generally not cross-compatible between systems. You can't use a Canon lens on a Nikon camera, for example. There are third-party manufacturers like Sigma and Zeiss, but you still can't take your Tamron lens for a Canon camera to a Pentax body if you decide to change systems. Sigma does offer a mount conversion service for its latest generation of lenses, but that's the exception to the rule.
Most shooters buying their first SLR will choose a model with an APS-C image sensor, roughly 16 by 24 millimeters in size. This is smaller than 35mm film, which measures 24 by 36 millimeters, a size matched by higher-end full-frame cameras like the Canon EOS 6D. You can buy a lens that only captures enough light to project an image circle that covers the entirety of the APS-C sensor, or you can get a full-frame lens with an eye on a future upgrade. Full-frame cameras are dropping in price, and if you really catch the photo bug you may want to upgrade down the lines.
A lens like the Canon EF-S 17-55mm f/2.8 IS USM can only be mounted to a Canon APS-C camera, but the company's EF 16-35mm f/2.8L USM is compatible with full-frame and APS-C bodies alike. When mounted on the Rebel T6s, both lenses will cover a similar field of view, but if you put the 16-35mm on the full-frame 6D, it will capture a much wider angle. The EF-S 17-55mm won't physically fit on the 6D, but that's a limitation exclusive to the Canon system. If you shoot with a Nikon, Pentax, or Sony camera, APS-C lenses will fit on full-frame bodies—but you will be limited to shooting at a lower resolution, as the camera will crop photos to match the size of an APS-C sensor.
All four SLR makers—Canon, Nikon, Pentax, and Sony—offer both APS-C and full-frame models. Canon and Nikon have more models available, while Pentax is just releasing its first full-frame body, the K-1, this year. Sony only has a handful of SLRs in its lineup, as it has concentrated on its mirrorless camera system in recent years.
We've also got mirrorless shooters covered with overviews of the best lenses for Micro Four Thirds, Samsung NX, and Sony E systems. If you use a rangefinder, film, or digital, you can also look at the best Leica M lenses that we've reviewed.
If you're persusing this list in anticipation of choosing an SLR system, take a look at our roundups of the Best DSLRs and the Best Full-Frame DSLRs. We've also highlighted our favorite Mirrorless Cameras, and you can see all of the cameras and lenses we've reviewed in our Digital Cameras Product Guide.