Ask me how I feel about the zoom lenses in my collection, and I’ll tell you they’re pretty darn fantastic: ultra sharp wide open, versatile, and plenty fast for the vast majority of shooting scenarios (which, for me, revolve mostly around food).
And yet, I rarely ever use them.
They stick around, really, because I keep telling myself they’ll be useful on vacations, when I won’t want to carry around a backpack full of primes, or on some mythical shoot where I’m allowed to bring only one lens and given no clues as to my subject or environment (e.g., dragons, yeti, crystal skulls).
That mythical shoot, of course, has yet to come, and my zooms have yet to experience a beach or a theme park; instead, they’ve sat idle while I added yet another prime to my bag specifically for travel, a barely visible pancake lens that makes up for in portability—among other characteristics—what it lacks in versatility or speed.
For the uninitiated, prime lenses allow you to access one—and only one—focal length; if you’re behind a prime and fancy a tighter shot, you’ll need to take a step forward—or, perhaps, a hundred steps forward, depending on your desired view. Camera-mounted primes date back to the inception of cameras and pre-date zoom technology by roughly a century; that doesn’t make them better or worse, of course, but their simplified designs do offer some inherent advantages.
For starters, the fixed distance between the glass and the camera’s sensor or film element makes for a highly simplified internal design. There’s less complexity of movement to worry about and no sliding scale for focal length, which can make it much easier to solve for challenges like ghosting (e.g., reflected orbs) and chromatic aberration (e.g., purple fringes). Take away the zoom elements, and it’s also easier to achieve maximum sharpness—as your lens doesn’t have to function acceptably across many focal lengths, just with excellence in one.
The technology behind zoom lenses has come a long way, of course, and there are no shortages of super sharp zooms available for a variety of camera systems; however, primes generally retain the edge when it comes to image quality—particularly when shot wide open, which brings us to the topic of aperture.
Prior to Sigma’s 2013 release of the 18-35mm F1.8 DC HSM (which plays nicely with crop sensors only), the widest aperture we were accustomed to finding on DLSR zoom lenses was f/2.8—or two stops fewer than typical f/1.4 primes, which thereby let in four times the light. That gives primes a significant advantage in low light, action, and natural light shooting.
Alongside that aperture, of course, comes a shallower depth of field, enhancing your ability to isolate subjects and soften their backgrounds.
Still, a lot of these advantages come down to pixel peeping; give an ordinary kit lens to the right person, and they’ll overcome these limitations by shooting strategically—which, for me, is the real attraction to using primes.
Shooting with zooms can be dangerously easy—to the point that legitimate challenges become rare. Using zooms, it can be far easier to grow lazy; just one twist of your fingers around the barrel and you can shoot most anything in sight without lifting a foot. Throw on a fixed 35mm, 50mm, or 90mm, however, and you might be forced to move around a bit, get creative, and think about your shots before you start to capture them.
The gain doesn’t come from your shots being difficult or taking more time—as there’s no harm done in saving time or energy—but rather in forcing yourself to raise questions and adapt. (It’s for this same reason that it helps to test out your angles before you unpack your tripod or dolly, lest you be tempted to simply stand and pivot in lieu of exploring your full range of options.)
The more you study one focal length, the more comfort you’ll gain with it and the easier it will be to find your shots without looking through a viewfinder. I simply don’t have to think as much when I shoot with primes; they feel more like a natural extension, whereas zooms tend to feel somehow “in the way” between my eye and my subject.
This isn’t to say you can’t challenge yourself equally with a zoom or yield the same (or better) results; of course you can. It’s just that you’ll have to challenge yourself not to take the easy route each time you twist the barrel.
Matt Siegel writes about stock footage, prime lenses, and footage involving delicious octopus for VideoBlocks.