Samyang 20mm f/1.8 ED AS UMC Specs, Equivalents & Depth of Field

20 mm

Focal length

f/1.8

Maximum aperture

94°

Diagonal angle of view (Full frame)

Full frame

Designed for

Specifications#

Brand: Samyang
Model: 20mm f/1.8 ED AS UMC
Lens type: Ultra-wide prime
Focal length: 20 mm
Maximum aperture: f/1.8
Image circle: Full frame (36×24 mm)
Mount(s): Pentax K, Canon EF, Nikon F, Fujifilm X-mount, Sony / Minolta A-mount, Sony E-mount, Micro Four Thirds, Samsung NX, Canon EF-M
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 20 mm	Equiv. aperture (DoF)
Full frame	20 mm · 94°	f/1.8
APS-C	30 mm · 70°	f/2.7
APS-C (Canon)	32 mm · 68°	f/2.9
Micro Four Thirds	40 mm · 57°	f/3.6

Depth of field & background blur#

Computed on its native Full frame format (CoC 30 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/1.8 on full frame.

Focal	Aperture	at 1 m	at 2 m	at 5 m	at 10 m	Hyperfocal	Blur @2 m
20 mm	f/1.8	26.9 cm	1.15 m	12.3 m	∞	7.43 m	0.3%
20 mm	f/4	64.4 cm	3.67 m	∞	∞	3.35 m	0.1%
20 mm	f/8	1.80 m	∞	∞	∞	1.69 m	0.1%

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 20 mm	NPF at 20 mm, f/1.8
Full frame	1/20 s	25 s	12 s
APS-C	1/30 s	17 s	9 s
APS-C (Canon)	1/30 s	16 s	9 s
Micro Four Thirds	1/40 s	12 s	8 s

Compatible cameras#

Bodies in our database with a native Pentax K, Canon EF, Nikon F, Fujifilm X-mount, Sony / Minolta A-mount, Sony E-mount, Micro Four Thirds, Samsung NX and Canon EF-M mount.

Adapt it to other systems#

Sony E-mount Canon RF Nikon Z Fujifilm X-mount Micro Four Thirds L-Mount Canon EF-M Fujifilm G-mount Hasselblad XCD Nikon 1 (CX)Pentax Q Samsung NX Canon EF Nikon F

Similar lenses#

Sony FE 20mm f/1.8 G f/1.8
Sigma 20mm F2 DG DN | Contemporary 022 f/2
Tamron 20mm F2.8 Di III OSD M1:2 f/2.8
Viltrox AF 20mm F2.8 Z f/2.8
Viltrox PFU RBMH 20mm f/1.8 ASPH f/1.8
Canon EF 20mm f/2.8 USM f/2.8
Nikon Nikkor AF 20mm f/2.8D f/2.8
Nikon Nikkor AF-S 20mm f/1.8G ED f/1.8
Nikon Nikkor AI 20mm f/3.5 f/3.5
Nikon Nikkor AI-S 20mm f/2.8 f/2.8
Sigma 20mm f/1.4 DG HSM | A f/1.4
Sigma 20mm f/1.8 EX DG f/1.8

Frequently asked questions#

Is the Samyang 20mm f/1.8 ED AS UMC full frame?

Yes — it covers the full 36 × 24 mm frame.

What is the Samyang 20mm f/1.8 ED AS UMC equivalent to on APS-C?

On a 1.5× APS-C body it frames like 30 mm, and like 32 mm on Canon APS-C.

What is the Samyang 20mm f/1.8 ED AS UMC good for?

As a ultra-wide prime it suits astrophotography, landscapes and dramatic perspectives.

Sources & licences#

Lensfun lens database — CC BY-SA 3.0