Focal Lengths — FocalMath

25 common focal lengths, from 8mm fisheye-territory ultra-wides to 600mm super-telephotos, each covered on its own terms rather than crossed against every sensor and aperture combination — that combinatorial approach produces thousands of near-identical thin pages, which is exactly the kind of low-value bulk this site deliberately avoids.

Each focal-length page covers what that length actually does: its typical field of view (which depends on sensor format, covered separately on the sensor pages and in the crop-factor tool), the kind of perspective and compression it produces, common uses it's genuinely suited to, and where it starts to struggle. A 24mm behaves very differently from a 200mm well beyond "one is wider than the other" — background compression, minimum focus distance, and how forgiving the depth of field is at a given aperture all change meaningfully across this range.

For a focal length's actual depth-of-field or hyperfocal-distance numbers on your specific sensor, use the DoF & Hyperfocal Calculator rather than trying to interpolate from a chart — the calculator accounts for your real sensor format, which a generic focal-length page can't.

The Range Covered

Every entry here is a real, individually distinct focal length with its own page — never a generated span pulled from a spreadsheet. The specific 25 values chosen reflect the lengths that actually show up as marked stops on real zoom lenses and as common prime-lens options across major camera systems, rather than an arbitrary evenly-spaced list.

The 25 lengths here run from 8mm (a circular or diagonal fisheye on most systems, or an extreme rectilinear ultra-wide) up to 600mm (a serious super-telephoto used for distant wildlife and sports). In between sit the workhorse ranges most photographers actually own: wide-angle landscape and architecture lenses in the 14-24mm range, versatile standard zooms and normal primes around 24-70mm, portrait-friendly short telephotos around 85-135mm, and general telephoto reach from 150mm up through 300mm and beyond.

Field of view for any of these lengths depends on sensor format — the same focal length frames tighter on a smaller sensor because of crop factor, which is covered separately on the sensor pages and directly in the Crop-Factor & Equivalence Converter. Perspective compression is genuinely a property of the focal length and subject distance alone, and doesn't change with sensor format the way field of view does — but depth of field at a given real focal length and aperture DOES vary by sensor format, through circle of confusion, which is a separate effect covered on each sensor page. Each page here notes the equivalent field of view across the most common sensor formats, so you don't need to run the converter separately just to sanity-check a lens purchase before committing to it.