Sigma 18-125mm f/3.5-5.6 DC Specs, Equivalents & Depth of Field

18–125 mm

Focal length

f/3.5–5.6

Maximum aperture

76°–13°

Diagonal angle of view (APS-C)

APS-C

Designed for

6.9×

Zoom ratio

Specifications#

Brand: Sigma
Model: 18-125mm f/3.5-5.6 DC
Lens type: Standard zoom
Focal length: 18–125 mm
Maximum aperture: f/3.5–5.6
Image circle: APS-C (23.5×15.6 mm)
Mount(s): Sigma SA, Canon EF, Nikon F, Pentax K, Four Thirds
Projection: Rectilinear
Lensfun correction profile: Yes — distortion/vignetting/TCA

Equivalent focal length on different cameras#

Field of view and depth-of-field equivalence when this lens is used on bodies with different sensor sizes (natively or via an adapter).

Camera format	At 18 mm	At 47 mm	At 125 mm	Equiv. aperture (DoF)
APS-C	27 mm · 76°	70 mm · 33°	188 mm · 13°	f/5.2
APS-C (Canon)	29 mm · 73°	75 mm · 32°	200 mm · 12°	f/5.6
Micro Four Thirds	36 mm · 62°	94 mm · 26°	250 mm · 10°	f/7.0

Depth of field & background blur#

Computed on its native APS-C format (CoC 20 µm). “Blur @2 m” is the size of an out-of-focus point at infinity, as a percentage of frame width, with the subject at 2 m — a simple bokeh index. Full table: 20 mm f/4 on aps-c.

Focal	Aperture	at 1 m	at 2 m	at 5 m	at 10 m	Hyperfocal	Blur @2 m
18 mm	f/3.5	43.4 cm	2.03 m	∞	∞	4.75 m	0.2%
18 mm	f/4	50.2 cm	2.48 m	∞	∞	4.16 m	0.2%
18 mm	f/8	1.22 m	45.6 m	∞	∞	2.09 m	0.1%
47 mm	f/3.5	5.9 cm	24.3 cm	1.57 m	6.82 m	32.3 m	1.4%
47 mm	f/4	6.8 cm	27.8 cm	1.81 m	8.05 m	28.3 m	1.2%
47 mm	f/8	13.6 cm	56.4 cm	4.00 m	28.0 m	14.2 m	0.6%
125 mm	f/3.5	0.8 cm	3.3 cm	21.4 cm	86.7 cm	228 m	10.1%
125 mm	f/4	0.9 cm	3.8 cm	24.4 cm	99.1 cm	200 m	8.9%
125 mm	f/8	1.8 cm	7.5 cm	48.9 cm	2.00 m	100.0 m	4.4%

Handheld & night-sky limits#

NPF assumes typical 20–24 MP sensors (≈6 µm pixels on full frame, ≈3.9 µm on APS-C, ≈3.3 µm on Micro Four Thirds).

Body	Min. handheld shutter (longest focal)	500 rule at 18 mm	NPF at 18 mm, f/3.5
APS-C	1/200 s	19 s	13 s
APS-C (Canon)	1/200 s	17 s	13 s
Micro Four Thirds	1/250 s	14 s	12 s

Compatible cameras#

Bodies in our database with a native Sigma SA, Canon EF, Nikon F, Pentax K and Four Thirds mount. Full-frame bodies switch to an APS-C crop with this lens.