Pentax smc Pentax-A 20mm f/2.8 vs Sigma 20mm f/1.8 EX DG ASPHERICAL RF
Both are Pentax K prime lenses for full frame. Here is what actually differs.
Pick the Pentax smc Pentax-A 20mm f/2.8 if
Our spec data shows no clear advantage for this lens.
Pick the Sigma 20mm f/1.8 EX DG ASPHERICAL RF if
- You need 1⅓ stops more light for low light or background blur (f/1.8 vs f/2.8)
- You shoot close-ups: it focuses down to 0.2 m vs 0.25 m
Spec differences
8 differences| Pentax smc Pentax-A 20mm f/2.8 | Sigma 20mm f/1.8 EX DG ASPHERICAL RF | |
|---|---|---|
| Brand |
Pentax
|
Sigma
|
| Max aperture |
f/2.8
|
f/1.8
1⅓ stops faster
|
| Filter thread |
67 mm
|
82 mm
|
| Min focus distance |
0.25 m
|
0.2 m
closer
|
| Max magnification |
not listed
|
0.25×
|
| Aperture blades |
not listed
|
9
|
| Optical design |
10 elements / 9 groups
|
13 elements / 11 groups
|
| Autofocus motor |
Manual focus
|
not listed
|
5 identical specs hidden: mount, type, format, focal length, image stabilization. Show all
- Mount
- Pentax K both
- Type
- Prime both
- Format
- Full frame both
- Focal length
- 20mm both
- Image stabilization
- No both
Our notes
Pentax smc Pentax-A 20mm f/2.8
The Pentax smc Pentax-A 20mm f/2.8 is a wide-angle prime lens covering 20mm at f/2.8 for Pentax K mount cameras. The wide view suits landscapes, architecture and environmental shots.
Our notes
Sigma 20mm f/1.8 EX DG ASPHERICAL RF
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Samyang 20mm T1.9 ED AS UMC: 1 stop faster, focuses closer
Samyang 20mm T1.9 ED AS UMC vs Sigma 20mm f/1.8 EX DG ASPHERICAL RF
Samyang 20mm f/1.8 ED AS UMC vs Pentax smc Pentax-A 20mm f/2.8
Samyang 20mm f/1.8 ED AS UMC: 1⅓ stops faster, focuses closer
Pentax smc Pentax-FA 20mm f/2.8 vs Sigma 20mm f/1.8 EX DG ASPHERICAL RF
Sigma 20mm f/1.8 EX DG ASPHERICAL RF: 1⅓ stops faster, focuses closer