Sigma 20mm f/2 DG DN Contemporary (L-mount) vs Sigma 45mm f/2.8 DG DN Contemporary (L-mount)
The bottom line
These cover different focal lengths — the Sigma 20mm f/2 DG DN Contemporary (L-mount) is 20mm, the Sigma 45mm f/2.8 DG DN Contemporary (L-mount) is 45mm — so they're not really substitutes. Pick by the field of view you actually need: the Sigma 20mm f/2 DG DN Contemporary (L-mount) for wide-angle, the Sigma 45mm f/2.8 DG DN Contemporary (L-mount) for short-telephoto / portrait.
Choose the Sigma 20mm f/2 DG DN Contemporary (L-mount) if…
- ✓You want more light and background blur — f/2 is faster than f/2.8, better for low light and subject separation.
- ✓You shoot wide — it starts at 20mm vs 45mm for landscapes, interiors and architecture.
- ✓You work outdoors — it's weather-sealed against dust and moisture; the other isn't.
Choose the Sigma 45mm f/2.8 DG DN Contemporary (L-mount) if…
- ✓You need more reach — it goes to 45mm vs 20mm for distant subjects, wildlife and sport.
- ✓You value portability — at 215g (7.6 oz) it's lighter than the 370g (13.1 oz) alternative for travel and all-day carry.
Where they differ
- ›Aperture: the Sigma 20mm f/2 DG DN Contemporary (L-mount) opens to f/2 vs the Sigma 45mm f/2.8 DG DN Contemporary (L-mount)'s f/2.8 — more light and shallower depth-of-field.
- ›Focal range: Sigma 20mm f/2 DG DN Contemporary (L-mount) is 20mm, Sigma 45mm f/2.8 DG DN Contemporary (L-mount) is 45mm — different framing and reach.
- ›Weight: the Sigma 45mm f/2.8 DG DN Contemporary (L-mount) is 215g (7.6 oz) vs 370g (13.1 oz) — you'll feel the difference handheld.
- ›Durability: the Sigma 20mm f/2 DG DN Contemporary (L-mount) is weather-sealed; the other isn't.
Frequently asked
Is the Sigma 20mm f/2 DG DN Contemporary (L-mount) or the Sigma 45mm f/2.8 DG DN Contemporary (L-mount) better?
These cover different focal lengths — the Sigma 20mm f/2 DG DN Contemporary (L-mount) is 20mm, the Sigma 45mm f/2.8 DG DN Contemporary (L-mount) is 45mm — so they're not really substitutes. Pick by the field of view you actually need: the Sigma 20mm f/2 DG DN Contemporary (L-mount) for wide-angle, the Sigma 45mm f/2.8 DG DN Contemporary (L-mount) for short-telephoto / portrait.
Who should choose the Sigma 20mm f/2 DG DN Contemporary (L-mount)?
Choose the Sigma 20mm f/2 DG DN Contemporary (L-mount) if you want more light and background blur — f/2 is faster than f/2.8, better for low light and subject separation. Choose it if you shoot wide — it starts at 20mm vs 45mm for landscapes, interiors and architecture. Choose it if you work outdoors — it's weather-sealed against dust and moisture; the other isn't.
Who should choose the Sigma 45mm f/2.8 DG DN Contemporary (L-mount)?
Choose the Sigma 45mm f/2.8 DG DN Contemporary (L-mount) if you need more reach — it goes to 45mm vs 20mm for distant subjects, wildlife and sport. Choose it if you value portability — at 215g (7.6 oz) it's lighter than the 370g (13.1 oz) alternative for travel and all-day carry.
What is the main difference between the Sigma 20mm f/2 DG DN Contemporary (L-mount) and the Sigma 45mm f/2.8 DG DN Contemporary (L-mount)?
Aperture: the Sigma 20mm f/2 DG DN Contemporary (L-mount) opens to f/2 vs the Sigma 45mm f/2.8 DG DN Contemporary (L-mount)'s f/2.8 — more light and shallower depth-of-field.
| Product | ||
|---|---|---|
| Optical Design | ||
| Focal Length | 20mm | 45mm |
| Lens Type | Prime | Prime |
| Optical Elements | 13 | 10 |
| Optical Groups | 11 | 8 |
| Aperture & Iris | ||
| Maximum Aperture | f/2 | f/2.8 |
| Minimum Aperture | f/16 | f/22 |
| Aperture Blades | 9 | 9 |
| Rounded Aperture | Yes | Yes |
| Coverage & Angle | ||
| Format Coverage | Full-Frame | Full-Frame |
| Lens Mount | L-Mount | L-Mount |
| Angle of View | 94° | 51° |
| 35mm Equivalent | − | − |
| Focus | ||
| Autofocus | Yes | Yes |
| Focus Motor | HLA | STM |
| Focus Limiter | No | No |
| AF/MF Switch | Yes | Yes |
| Min Focus Distance | 22 cm | 24 cm |
| Max Magnification | 0.19x | 0.19x |
| Stabilization & Video | ||
| Optical Stabilization | No | No |
| Aperture Ring | Yes | Yes |
| Declickable Aperture | Yes | Yes |
| Parfocal | No | No |
| Internal Zoom | No | No |
| General | ||
| Price (MSRP) | $549 | $599 |
| Filter Size | 67mm | 55mm |
| Diameter | 74.8mm | 62.6mm |
| Length | 90.5mm | 46.2mm |
| Weight | 370g (13.1 oz) | 215g (7.6 oz) |
| Weather Sealed | Yes | No |
| Tripod Collar | No | No |
