A common debate with photographers is about focal lengths: whether you should invest the bucks in a zoom/telephoto lens or hold on to that prime, save the money and frame the shot by walking closer or farther from your subject. This is commonly called “zooming with your feet.”
You certainly can do this, but there is still a flaw to the “zoom with your feet” concept that it’s evangelists are leaving out. Let’s put some pictures up to demonstrate.
This first picture was taken in a field on a lazy Sunday in Augusta, MO. At 35mm, I had to get fairly close in order to frame the composition in the way I wanted. Aside from the scoreboard, you’ll notice the vast field and sky along with the power plant far off into the distance. This would be the result of “zooming with my feet” with a short lens.
Next, let’s back up and take the same picture at 180mm.
The scoreboard looks the same as expected but the background is an entirely different story. The power plant that looked so tiny in the other photo now looks gigantic. The rest of the background looks more compressed, with the field much narrower and the sky focused on the lower clouds.
The reason this happens on longer lenses has to do with your change of perspective. And that’s why the argument of zooming with your feet is a fallacy: you still get different results with lenses of different focal lengths based on your distance and perspective.
Regardless, this still isn’t to say that one focal length is better than the other. The photo shot at 35mm better displays the vast sky and landscape, both of which is lost on the photo shot at 180mm. However, the background you get from shooting at a long distance may come in handy with subjects in the foreground that you’re wanting to isolate, or you can accentuate impressive elements in the background that you don’t want to look minuscule (like buildings or mountains).
Neither way is right or wrong, it’s up to you to decide what effect you’re after. But no matter where you move your feet, don’t expect one lens length to do it all; it’s well worth owning a zoom or primes of different lengths in order to explore different perspectives, options and effects available to you.