Micro 4/3	5 mm	8 mm	12 mm	15 mm	18 mm	26 mm	44 mm	52 mm	70 mm	104 mm	156 mm	260 mm
APS-C	7 mm	11 mm	16 mm	19 mm	23 mm	33 mm	57 mm	67 mm	90 mm	133 mm	200 mm	333 mm
35mm	10 mm	16 mm	24 mm	28 mm	35 mm	50 mm	85 mm	100 mm	135 mm	200 mm	300 mm	500 mm
6x4.5	16 mm	26 mm	39 mm	45 mm	56 mm	81 mm	137 mm	161 mm	217 mm	322 mm	483 mm	805 mm
6x6	18 mm	29 mm	44 mm	51 mm	64 mm	92 mm	155 mm	183 mm	247 mm	366 mm	548 mm	915 mm
6x7	20 mm	32 mm	48 mm	56 mm	71 mm	101 mm	171 mm	202 mm	272 mm	404 mm	604 mm	1009 mm
6x8	22 mm	35 mm	53 mm	62 mm	77 mm	110 mm	187 mm	220 mm	297 mm	440 mm	660 mm	1100 mm
6x9	23 mm	37 mm	56 mm	65 mm	82 mm	117 mm	198 mm	233 mm	315 mm	467 mm	700 mm	1167 mm
4x5	36 mm	57 mm	85 mm	99 mm	124 mm	177 mm	301 mm	354 mm	478 mm	708 mm	1061 mm	1769 mm
8x10	71 mm	113 mm	170 mm	198 mm	248 mm	354 mm	601 mm	707 mm	955 mm	1415 mm	2122 mm	3537 mm

35mm Focal Length Equivalents

This web page helps you find the 35mm/full-frame equivalent to a focal length in a different sensor- or film-format.

Like a lot of photographers, you might be familiar with focal lengths in the 35mm/full-frame image format and what field of view that focal length represents (24 mm = wide angle, 50 mm = “normal” etc.). Different formats, however, require different focal length lenses to produce an equivalent field of view.

With this site, you can look up and calculate these focal lengths and their 35mm-equivalents.

Calculation

The equivalent focal lengths are calculated based on the diagonal of each imaging format.

For example:
35mm format diagonal ≈ 43.3 mm.
APS-C format diagonal ≈ 28.8 mm

Diagonal ratio: 43.3 mm / 28.8 mm ≈ 1.5

50 mm in APS-C ≈ 75 mm in 35mm/full-frame format, because 50 mm * 1.5 = 75 mm.

Using a diagonal-based calculation (instead of width- or height-based) is not ideal when the aspect ratios of the compared formats vary (greatly), as is for example the case when comparing full-frame with its 3:2 aspect ratio to, say, 6x6, which is a square format. However, this still seems to be the most popular and useful way to make this comparison.