Lens Compression: Does It Exist?
It’s easy for photographers to assume lenses affect the compression of a shot. The belief is that a wide-angle lens will distort the subject and cause the background to look much further away than it is.
If you take a few steps back and switch to a telephoto lens, the subject and background will appear closer together, or “compressed.”
Many photographers make the mistake of assuming it’s the lens that creates this compression effect — hence the term “lens compression,” after all. In truth, it’s not actually a result of your choice of lens. This distortion is created by the distance between you, your subject, and the background.
Why Lens Compression Doesn’t Exist
Lee Morris over at Fstoppers conducted an interesting study to demonstrate that “a wide-angle lens cropped in and a telephoto lens will create the same amount of foreground and background ‘compression,’” so long as the camera remains in the same place.
As shown in Morris’s sample photos, compression occurs when you increase the distance between yourself, your subject, and the background. To halve the size of a subject that is one foot away, you would need to move back another foot. At the same time, the background remains almost identical — it doesn’t become halved at all.
That’s because your subject is so close, and the background so far, that the ratio dictates your subject grows smaller faster. In order to maintain the same size of your subject, you will need to zoom in or crop the photo afterward.
What’s Actually Happening Then?
What’s happening in any of these situations isn’t actually lens compression, but perspective distortion. The distance from your camera to your subject is what causes distortion.
The term “lens compression” should, as Morris states in his YouTube video, be replaced by something more akin to “perspective compression.”
This knowledge won’t affect how you shoot photos, of course, but it’s an interesting technicality that explains a phenomenon we’re all quite used to.