Many photographers think focal length affects perspective. They think wide angle lenses exaggerate perspective, and telescopic lenses flatten perspective.
Technically speaking, that's not true. All focal lengths show perspective identically.
Some of you might be thinking, "But I've seen exaggerated perspective with wide angle lenses and flattened perspective with telescopic lenses". So, what's going on?
Here's the way it's actually working:
In order for a wide angle lens and a telephoto lens to exactly fit a subject of the same size (such as a yardstick fitting exactly across the length of the frame), the wide angle lens needs to be closer to the subject than the telephoto lens. If we wanted to exactly fill the frame with a yardstick, using a 24 mm lens on a 35 mm format camera, we'd need to be about 2 feet away. To similarly fill the frame with a yardstick, using a 600 mm lens, we'd need to be a little over 49 feet away.
Now imagine there's a second yardstick, a blue one, two feet behind the first one, which we'll say is yellow. As you photograph the yellow yardstick with the 24 millimeter lens from 2 feet away, the blue yardstick will be 4 feet away – twice the distance from your lens – which means the blue yardstick will look half as large as the yellow one in your picture. By comparison, when photographed with the 600 millimeter lens, the blue yardstick is 51 feet away – about 4% farther away than the yellow yardstick 49 feet away, which means it will look 2% smaller in your picture.
Thus, while all lenses actually show perspective the same way, the way we use lenses, due to their focal lengths, gives us the appearance of different perspectives. The way wide angle lenses usually get used (comparatively closer to subjects) appears to "exaggerate" perspective; the way telephoto lenses usually get used (comparatively farther from subjects) appears to "compress" perspective.
If you used both the 24 mm lens and the 600 mm lens from 49 feet away, and then cropped the 24 mm picture down to where it covered the same area as the 600 mm picture, then compared the two shots side by side, you'd see that the perspective in the two pictures is identical.
View East of Tioga Pass, Near Yosemite National Park, California
All pictures and text are © Mike Spinak, unless otherwise noted. All pictures shown are available for purchase as fine art prints, and are available for licensed stock use. Telephone: (831) 325-6917.