If you’re a photographer snapping on a prime lens for the first time, you might be given the glib advice that you’ll have to “zoom with your feet.” Be sure not to take this the wrong way…
“Ehsan the Shooter” by Hamed Saber (cc-by)
On the surface, this injunction may sound like a mockery of the technological simplicity of the humble prime lens. Unlike the plethora of ranged zoom lenses that have become commonplace among modern photographers, the prime lens (or fixed lens) shoots at one focal length only–in other words, it can not zoom.
The suggestion that you might be able to “zoom with your feet” is not even technically correct, at least not in the sense that to “zoom” means to increase the focal length towards a telephoto view. Changing the focal length of a lens adjusts how strongly the lens will converge or diverge beams of light, resulting in a different angle of view, effectively increasing or decreasing magnification.
A prime lens, with its fixed focal length, will collect light beams from one specific angle of view. Thus, to “magnify” your subject, you must in fact position yourself closer, or walk towards it on your feet. But the perspective you capture will be different than if you had shot at a different focal length without changing your position.
So why opt for a fixed lens if it invokes the seeming hassle of having to stumble around searching for your desired viewpoint? Of course there are optical advantages of prime lens: compared to zoom lenses, they typically have wider apertures and sharper optics at a lesser price. But the necessity to “zoom with your feet” has its advantages as well, advantages less technical and more experiential, or artistic. Indeed, having to zoom with your feet provides much of the allure that draws photographers to prefer shooting with prime lenses.
In having to move your body more in the process of composing a pleasing photograph, you, the artist, will often find yourself interacting more strongly with your environment and perspectives that you never would have given the opportunity to simply slide the length of a zoom lens. In performing portrait photography, or street photography of people, zooming with your feet also has an especially important human dimension. By approaching closer to someone with a mid-length prime (such as a 50mm or 80mm lens) you must establish a rapport with your subject. This will bring out a liveliness in your shots that would not be captured in a more voyeuristic shot at a longer telephoto zoom.
Indeed, to “zoom with your feet” is the joy of the prime lens photographer. Dancing around with a simple fixed lens, you will interact with your world to a degree unimaginable by photographers replete with sophisticated and distancing equipment. Your visual sense will be informed by your activity and movement. And your photography will reflect this newfound creativity.
So zoom with your feet!