The most popular reason nonprofessionals buy dSLRs or other types of interchangeable-lens cameras is because they want better photos or faster performance than a point-and-shoot can deliver; the power of manual controls and interchangeable lenses seem to be a secondary concern. Nevertheless, I'm still routinely surprised when someone hands me his dSLR and it's set to auto and equipped with a standard kit lens.
The best (and cheapest) way to advance your photography is to switch out of auto; here's a map for venturing into that new territory. But the next best -- and not-so-cheap -- way to inject some new life into your photography is to try a new lens. (Know nothing about lenses? Jump to Basic terminology)
There are a variety of reasons to invest in a second or third lens -- if you're up to your third, chances are you don't need any encouragement from me. The first, and possibly most compelling, is that you simply can't get the shots you want with the lens you have, usually because most kit lenses have a limited telephoto range. On the flip side, you might be routinely frustrated by the inability to get everything you want in the photo, which requires a shorter focal length. Another reason to expand your options: better low-light photography. A lens with a maximum aperture wider than the standard f3.5 of most kit lenses allows for more light so that you the camera doesn't have to boost the ISO sensitivity into the noisy range or lower the shutter speed to the point where camera shake becomes a problem. And you can't usually maintain even that maximum aperture as you zoom out. A faster lens also delivers a more attractive, out-of-focus background with less work (though you can achieve the effect with slow lenses as well). If you're shooting more video, you might want a lens that's easier to manually focus or that provides quieter autofocus. Or you might simply want to climb out of a photography rut.
Trying a new lens or doesn't necessarily mean a huge cash outlay; lens rental services like LensRentals.com, LensProToGo.com and BorrowLenses.com have become quite popular, and it's a terrific, cost-effective way to see what it's like to shoot with a great pro lens that you normally wouldn't have access to or to buy refurbished. For example, you can rent a $1,700 Canon 100-400 f4.5-5.6L IS lens from LensProTogo for two weeks for just $168.
If you're looking to extend your zoom range, then the obvious choice is to bracket your kit lens with complementary wide angle and/or telephoto zoom. The most popular second lens tends to be a telephoto zoom with a focal length that starts at the end of the range of the typical kit lens; for example, 55-200mm for APS-C cameras or 75-300mm for MFT.
However, I've found a nice, fast prime is the best way to shake things up. Primes -- fixed focal-length lenses -- force you to think differently about framing a scene. Zooms provide flexibility when you're traveling because they're a compact way of covering a lot of territory, but primes expand your vision: since they don't have to be adequate at a lot of different focal lengths, they tend to be sharper at their designated focal length than the equivalent in a zoom, even the not-so-good ones. Furthermore, you can find a fast prime like a 35mm f2 or 50mm f1.8 for a lot less money than a fast zoom, and you get access to wide apertures that aren't possible on your kit lens. You'll immediately notice a difference in the quality of your photos. One warning, though: once you've shot with a fast lens, even a mediocre one, it's tough to go back to the slow zoom.
- Aperture: The opening that determines the amount of light to let through, as enumerated by an f-stop, such as f2.0. (It's referred to as an iris in video.) Lower f-stop numbers denote wider apertures. A camera with a wide aperture for much of the focal range is referred to as fast; narrow-aperture lenses are called slow. Apertures are formed by a series of blades that open and close; the more blades, the rounder the opening (seven or more is best). The downside: The faster the lens, the harder it can be to autofocus.
- Depth-of-field (DOF): The proportion of the image in front of and behind the subject that is sharp. When a photo has lots of background blur it displays shallow DOF. All things being equal -- notably sensor size and distance from subject -- the lower the f-number the shallower the DOF.
- Bokeh: The shape of out-of-focus highlights; rounder and smoother is usually considered better, unless you're going for an effect. Cheaper lenses are more likely to produce bokeh with concentric rings called Airy disks or rings (more detail here, for the mathematically inclined), though physics dictates that every lens has a point at which they'll occur.
- Focal length: Technically, the physical distance between the beginning of the optical path and the imaging plane (in this case, the sensor). However, the more informative spec is angle of view -- the degree of the scene that the lens covers -- which is dependent upon the size of the imaging plane. So as a convention everyone's adopted a 35mm frame of film as a standard size on which to base angle of view, and translates the physical focal length into the the focal length that produces the equivalent angle of view on a 35mm (full frame) camera by multiplying by a crop factor.
- Ultrawide angle (less than 18mm) is good for very large scenes where lens distortion adds rather than detracts from the appeal.
- Wide-angle (around 18mm to 30mm) is good for group shots, landscapes, and street photography
- Normal (about 30mm to 70mm) is good for portraits and snapshots
- Telephoto (about 70mm to 300mm) is good for portraits and sports
- Super telephoto (greater than 300mm) is good for sports, wildlife and stalking
- Lens mount: The place where a lens attaches to the camera. A lens must adhere to various specifications in order to be compatible with a camera -- the two most important specs that define a mount are size (so that they can match physically) and connectors (so that it can talk to the camera). Most mounts have third-party adapters that allow you to attach an incompatible lens, though there are frequently trade-offs like no autofocus, inability to work with the electronic metering system, or vignetting (darkness around the edges of the frame).
Popular consumer lens mounts and crop factors
|Manufacturer||Mount||Sensor size/crop factor|
|Both full frame/1.0x and APS-C/1.5x
|Pentax||K||Both full frame/1.0x and APS-C/1.5x|
|Olympus and Panasonic||Micro Four Thirds (MFT)||MFT/2.0x|