What is lens compression?

Lens compression (more accurately, perspective compression) makes the background appear larger and closer to the subject. It is caused by camera-to-subject distance, not focal length. When you use a telephoto lens, you stand further away — this distance creates the compression effect. Cropping a wide-angle shot from the same position gives identical compression.

Does focal length cause compression?

No — distance does. Focal length only determines magnification (how much of the scene you capture). Two photos taken from the same distance with different focal lengths show identical perspective when the wider one is cropped. The compression changes only when you move the camera.

How do I use compression creatively?

Use compression to make backgrounds appear closer (telephoto from far away) — great for bringing mountains behind a subject. Use wide-angle close up to exaggerate distance and depth. Portrait photographers use moderate compression (85-135mm on FF) for flattering facial proportions.

Why do wide-angle lenses distort faces?

When you photograph a face up close with a wide-angle lens, the nose is much closer to the camera than the ears. This distance difference is exaggerated, making the nose appear larger. At telephoto distances, the nose-to-ear distance is tiny relative to camera-to-subject distance, so proportions look natural.

Lens Compression Calculator — Perspective Compression

Visualise how perspective compression changes the apparent relationship between subject and background at different distances.

Subject Distance

Camera to subject

Background Distance

Camera to background

Subject Height

Subject height/width

Background Height

Background feature height

How We Calculate This

Perspective compression depends entirely on the ratio of distances:

Compression Ratio

Ratio = background distance / subject distance

Angular Size

Angular size = 2 x arctan(height / (2 x distance))

A higher compression ratio means the background appears proportionally larger relative to the subject. At a ratio of 10:1, the background is compressed to appear 10x closer than it actually is.

Frequently Asked Questions

Related Calculators

Crop Factor Calculator

Convert focal lengths between different sensor sizes using crop factor. Compare APS-C, Micro Four Thirds and full-frame equivalent fields of view. Free calculator.

Equivalent Focal Length Calculator

Find the full-frame equivalent focal length for any sensor size. Compare lenses across different camera systems with instant results. Free online calculator.

Field of View Calculator

Calculate horizontal, vertical and diagonal field of view for any lens and sensor combination. Plan shots and coverage before you shoot. Free calculator.

Magnification Calculator

Calculate optical magnification from focal length and subject distance. Determine image size on sensor for macro and close-up photography. Free online calculator.

Minimum Focus Distance Calculator

Find the working distance and maximum magnification at your lens minimum focus distance. Plan macro and close-up shots with precision. Free calculator.

Last updated: February 2026

All calculations are estimates based on standard optical and photographic formulas. Results may vary with specific equipment.