Looking to find more information regarding these two camera lenses? Check out our side by side comparison of the HD Pentax DA 21mm F3.2 AL Limited vs Sigma 20mm F1.8 EX DG Aspherical RFto review specs, pros and cons, and which is right for you.
Pentax 21mm F3.2 AL L Top Features
- 21mm Focal Range
- F3.2 Max Aperture
- Filter Thread: 49mm
- Max Format: APS-C / DX
- Pentax KAF Mount
- Weight: 134g.
- Diameter: 63mm
- Length: 25mm
- Min Focus Distance:0.2m
- Max Magnification:0.17x
Sigma 20mm F1.8 EX DG RF Top Features
- 20mm Focal Range
- F1.8 Max Aperture
- Filter Thread: 82mm
- Max Format:
- Pentax KAF Mount
- Weight: 520g.
- Diameter: 89mm
- Length: 90mm
- Min Focus Distance:0.2m
Our Winner: HD Pentax DA 21mm F3.2 AL Limited over Sigma 20mm F1.8 EX DG Aspherical RF
Focal Length – Tele
21mm
vs
20mm
1mm more Tele coverage
Weight
134g
vs
520g
386g lighter
Diameter
63mm
vs
89mm
26mm smaller in diameter
Length
25mm
vs
90mm
65mm shorter
Filter Thread
49mm
vs
82mm
Smaller filters are cheaper and easier to find
Max Magnification
0.17x
vs
x
higher magnification better for close-up shots
Focal Length – Wide
20mm
vs
21mm
1mm Wider coverage
Max Aperture – Wide
1.8
vs
3.2
Wider aperture at wide end
Max Aperture – Tele
1.8
vs
3.2
Wider aperture at tele end
Diaphgragm Blades
9
vs
7
Potentially more rounded and smooth bokeh
Aperture Ring
Yes
vs
No
able to adjust the aperture on the lens
Max Sensor Coverage
35mm FF
vs
APS-C / DX
covers larger sensors
Image Stabilization
No
vs
No
Reliant on in-body Image Stabilization
Weather Sealing
No
vs
No
not safe under rain and dust
Pentax 21mm F3.2 AL L vs Sigma 20mm F1.8 EX DG RF All Features
General
Pentax 21mm F3.2 AL L
Sigma 20mm F1.8 EX DG RF
Brand
Pentax
Sigma
Lens Type
Prime
Prime
Price
CHECK PRICE
CHECK PRICE
Lens Type
Wideangle Prime
Wideangle Prime
Lens Mount
Pentax KAF
Pentax KAF
Max Format
APS-C / DX
35mm FF
Focal Range
21mm
20mm
Image Stabilization
No
No
Colour
Black, Silver
Black
Zoom Method
No Zoom
No Zoom
Power Zoom
No
No
Zoom Lock
No
No
Zoom Ratio
1.0X
1.0X
Aperture
Max Aperture
F3.2
F1.8
Min Aperture
F22.0
F22.0
Aperture Ring
No
Yes
Diaphragm Blades
7
9
Optics
Optical Elements
8
13
Optical Groups
5
11
Special Elements
High-grade multi-layer HD (High Definition) Coating
2 aspherical elements
Focusing
Min Focus Distance
0.2m
0.2m
Max Magnification
0.17X
unknown
Autofocus
Yes
Yes
AF Motor Type
Screw drive from camera
unknown
Full Time Manual
Yes
Yes
Focus Method
Unknown
Rear
Distance Scale
Yes
Yes
DoF Scale
Yes
Yes
Distance Scale
Yes
Yes
Focus Distance Limiter
Unknown
Unknown
Physical Specs
Weight
134g
520g
Diameter
63mm
89mm
Length
25mm
90mm
Materials
Unknown
Unknown
Weather Sealing
Unknown
Unknown
Filter Thread
49mm
82mm
Filter Notes
–
–
Hood Supplied
Yes
Yes
Hood Code
MH-RBB43
petal type hood
Tripod Collar
No
No
Optional Accessories
–
–
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