Depth of field · APS-C

20 mm f/1.8 depth of field on APS-C

Exactly how much is sharp with a 20 mm lens at f/1.8 on an APS-C camera, from 30.0 cm to 100 m.

11.1 m
Hyperfocal distance
5.57 m
Sharp from (focused at hyperfocal)
31 mm f/2.8
Full-frame equivalent
70°
Diagonal angle of view

Depth of field by subject distance#

20 mm at f/1.8 on APS-C (23.5×15.6 mm), circle of confusion 20 µm. “Background blur” is the size of an out-of-focus light at infinity as a percentage of frame width.

Focus distanceNear limitFar limitTotal DoFFront / behindBackground blur
30.0 cm (0.98 ft)29.3 cm30.8 cm1.5 cm49% / 51%3.38%
50.0 cm (1.64 ft)47.9 cm52.3 cm4.3 cm48% / 52%1.97%
75.0 cm (2.46 ft)70.4 cm80.3 cm9.9 cm47% / 53%1.30%
1.00 m (3.28 ft)91.9 cm1.10 m17.8 cm46% / 54%0.96%
1.50 m (4.92 ft)1.32 m1.73 m40.7 cm43% / 57%0.64%
2.00 m (6.56 ft)1.70 m2.43 m73.6 cm41% / 59%0.48%
3.00 m (9.84 ft)2.37 m4.10 m1.73 m37% / 63%0.32%
4.00 m (13.1 ft)2.95 m6.23 m3.29 m32% / 68%0.24%
5.00 m (16.4 ft)3.45 m9.06 m5.61 m28% / 72%0.19%
7.00 m (23.0 ft)4.30 m18.8 m14.5 m19% / 81%0.14%
10.0 m (32.8 ft)5.27 m98.2 m93.0 m5% / 95%0.09%
15.0 m (49.2 ft)6.39 m∞∞—0.06%
20.0 m (65.6 ft)7.15 m∞∞—0.05%
30.0 m (98.4 ft)8.11 m∞∞—0.03%
50.0 m (164 ft)9.09 m∞∞—0.02%
100 m (328 ft)10.0 m∞∞—0.01%

Try other settings#

Near limit—
Far limit—
Depth of field—
Hyperfocal distance—
In front / behind—

20 mm at other apertures (subject at 3 m)#

ApertureTotal DoFHyperfocal
f/1.41.31 m14.3 m
f/1.81.73 m11.1 m
f/21.96 m10.0 m
f/2.83.03 m7.16 m
f/45.55 m5.02 m
f/5.616.5 m3.59 m
f/8∞2.52 m
f/11∞1.84 m
f/16∞1.27 m

Other focal lengths at f/1.8#

Focal lengthSubject atTotal DoF
14 mm3.00 m4.71 m
16 mm3.00 m3.06 m
20 mm3.00 m1.73 m
24 mm3.00 m1.16 m
28 mm3.00 m83.4 cm
35 mm3.00 m52.7 cm
40 mm3.00 m40.1 cm
50 mm3.00 m25.5 cm
85 mm3.00 m8.7 cm
105 mm3.00 m5.7 cm
135 mm3.00 m3.4 cm

Same lens settings on other formats#

20 mm f/1.8 on Full frame20 mm f/1.8 on Micro Four Thirds

When to use it#

At f/1.8, a 20 mm lens on APS-C is a natural choice for environmental portraits, street and low light. Focused at 3 m you get 1.73 m of sharp zone; for maximum front-to-back sharpness focus at 11.1 m and everything from 5.57 m to infinity will be acceptably sharp.

See also the f/1.8 aperture guide.

Frequently asked questions#

What is the depth of field of a 20mm lens at f/1.8?

On APS-C, focused at 3 m, it is 1.73 m; at 1 m it is 17.8 cm.

What is the hyperfocal distance for 20mm f/1.8?

11.1 m (36.5 ft) on APS-C. Everything from 5.57 m to infinity is acceptably sharp.

Last updated October 03, 2026 · How we calculate · Sources