Sigma 20mm F/1.8 EX DG Aspherical RF

Ultra-wide angle prime lens • Digital era • Discontinued

  • Announced:
  • · September 2000
  • Production status:
  • ● Discontinued
  • Country of design:
  • · Japan
  • Original name:
  • · SIGMA 20mm 1:1.8 EX DG ASPHERICAL
  • Class:
  • · Fast full-frame ultra-wide angle prime lens
  • · Professional model

Abbreviations

EX Professional lens with high quality optics and robust build. Meets the highest standards and provides excellent performance and flawless image quality unachievable with traditional optical technologies.
DG The lens is designed for 35mm digital cameras but can be also used on APS-C digital cameras.
RF Rear focusing.

Specification

Optical design:
35mm full frame
20mm
F/1.8
13 elements in 11 groups
2 ASPH
Internal focusing (IF)
Canon EF [44mm]
Minolta/Sony A [44.5mm]
Nikon F [46.5mm]
Pentax K [45.5mm]
Sigma SA [44mm]
94.5° (35mm full frame)
On Canon EOS APS-C [1.59x] cameras:
35mm equivalent focal length:
31.8mm (in terms of field of view)
35mm equivalent speed:
F/2.9 (in terms of depth of field)
Diagonal angle of view:
68.4°
On Sony DSLR-A/SLT-A APS-C [1.53x] cameras:
35mm equivalent focal length:
30.6mm (in terms of field of view)
35mm equivalent speed:
F/2.8 (in terms of depth of field)
Diagonal angle of view:
70.5°
On Nikon D APS-C [1.53x] cameras:
35mm equivalent focal length:
30.6mm (in terms of field of view)
35mm equivalent speed:
F/2.8 (in terms of depth of field)
Diagonal angle of view:
70.5°
On Pentax K APS-C [1.53x] cameras:
35mm equivalent focal length:
30.6mm (in terms of field of view)
35mm equivalent speed:
F/2.8 (in terms of depth of field)
Diagonal angle of view:
70.5°
On Sigma SD APS-C [1.74x] cameras:
35mm equivalent focal length:
34.8mm (in terms of field of view)
35mm equivalent speed:
F/3.1 (in terms of depth of field)
Diagonal angle of view:
63.7°
Diaphragm mechanism:
Diaphragm type:
Automatic
Aperture control:
None; the aperture is controlled from the camera (Canon EF, Minolta/Sony A, Sigma SA)
Aperture ring (Manual settings + Auto Exposure setting) (Nikon F, Pentax K)
9 (nine)
Focusing:
0.20m
0.065m
1:4
Focusing modes:
Autofocus (A), Manual focus (M)
Autofocus motor:
Micromotor (Canon EF, Sigma SA)
In-camera motor (Pentax K, Nikon F, Minolta/Sony A)
Manual focus control:
Focusing ring
Focus mode selector:
Sigma Dual Focus System (Canon EF, Sigma SA)
Focus Clutch Mechanism (Pentax K, Nikon F, Minolta/Sony A)
Manual focus override in autofocus mode:
-
Optical Stabilizer (OS):
-
Physical characteristics:
500g (Nikon F)
⌀88.6×87mm (Nikon F)
-
-
Accessories:
Screw-type 82mm
LH875-02 - Bayonet-type petal-shaped
Not compatible

Source of data

  • Manufacturer's technical data.

Manufacturer description

This super-wide-angle lens exhibits minimal light-fall-off with superior peripheral brightness. The iris diaphragm has 9 blades to obtain beautiful out of focus images in the foreground and background. This is an ideal DG lens optimized Digital SLR camera.

The minimum focusing distance of this lens is 20cm (7.9 inch) and it has maximum magnification of 1:4 with fast f/1.8 maximum aperture.

The lens incorporates Dual-Focus (DF) mechanism. It is easy to hold the lens, since the focusing ring does not rotate during auto-focus, yet it provides adequate focusing torque of the focusing ring during manual focusing of the lens. The rear focus system eliminates the need for the front of the lens to rotate, thus allowing the use of a "Petal-type hood".

The use of aspherical lens elements in both of the front and rear lens groups effectively compensates for distortion, spherical aberration and astigmatism.

Notes

  • The autofocus will not be available with Nikon D40, D40X, D60, D3000-D3500, D5000-D5600 digital SLR cameras.

Lenses with similar focal length

■Canon EF mount (5)
Canon EF 20mm F/2.8 USM • ⌀72Pro 1992 ●compare32
Sigma 18mm F/3.5 ZEN • ⌀72Pro 1992 ●compare32
Sigma 20mm F/1.4 DG HSM | APro 2015 ●compare33
Tokina AT-X Pro AF 17mm F/3.5 Aspherical • ⌀77Pro 1999 ●compare12
Tokina AT-X AF 17mm F/3.5 Aspherical • ⌀72Pro 1993 ●compare22
■Minolta/Sony A mount (6)
Minolta AF 20mm F/2.8 RS • ⌀72Pro 1993 ●compare42
Minolta AF 20mm F/2.8 • ⌀72Pro 1986 ●compare42
Sigma 18mm F/3.5 ZEN • ⌀72Pro 1992 ●compare32
Sony 20mm F/2.8 [SAL20F28] • ⌀72Pro 2006 ●compare41
Tokina AT-X Pro AF 17mm F/3.5 Aspherical • ⌀77Pro 1999 ●compare12
Tokina AT-X AF 17mm F/3.5 Aspherical • ⌀72Pro 1993 ●compare22
■Nikon F mount (8)
Nikon AF Nikkor 20mm F/2.8D • ⌀62Pro 1994 ●compare42
Nikon AF Nikkor 18mm F/2.8D • ⌀77Pro 1994 ●compare22
Nikon AF-S Nikkor 20mm F/1.8G ED • ⌀77Pro 2014 ●compare40
Nikon AF Nikkor 20mm F/2.8 • ⌀62Pro 1989 ●compare32
Sigma 18mm F/3.5 ZEN • ⌀72Pro 1992 ●compare32
Sigma 20mm F/1.4 DG HSM | APro 2015 ●compare33
Tokina AT-X Pro AF 17mm F/3.5 Aspherical • ⌀77Pro 1999 ●compare12
Tokina AT-X AF 17mm F/3.5 Aspherical • ⌀72Pro 1993 ●compare22
■Pentax K mount (2)
smc Pentax-FA 20mm F/2.8 • ⌀67Pro 1995 ●compare32
HD Pentax-D FA 21mm F/2.4 ED DC WR Limited • ⌀67Pro 2021 ●compare60
■Pentax K mount (2) · APS-C
smc Pentax-DA 21mm F/3.2 AL Limited • ⌀49 • Pancake lens 2006 ●compare61
HD Pentax-DA 21mm F/3.2 AL Limited • ⌀49 • Pancake lens 2013 ●compare71
■Sigma SA mount (2)
Sigma 18mm F/3.5 ZEN • ⌀72Pro 1992 ●compare32
Sigma 20mm F/1.4 DG HSM | APro 2015 ●compare33

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