Sigma 18-50mm f/2.8 DC DN Contemporary (L-mount) vs Sigma 20mm f/2 DG DN Contemporary (L-mount)
The bottom line
The Sigma 18-50mm f/2.8 DC DN Contemporary (L-mount) is a zoom (18-50mm) and the Sigma 20mm f/2 DG DN Contemporary (L-mount) is a 20mm prime. The zoom gives you framing flexibility from one lens; the prime trades that for a fixed focal length that's usually brighter (f/2 vs f/2.8) and lighter to carry. Choose flexibility or a fast single focal length.
Choose the Sigma 18-50mm f/2.8 DC DN Contemporary (L-mount) if…
- ✓You need more reach — it goes to 50mm vs 20mm for distant subjects, wildlife and sport.
- ✓You want one-lens flexibility — a 18-50mm zoom covers what the fixed 20mm can't reframe.
- ✓You value portability — at 290g (10.2 oz) it's lighter than the 370g (13.1 oz) alternative for travel and all-day carry.
- ✓You like close-focus work — 0.5x magnification vs 0.19x.
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 prefer a fast, compact single focal length — a 20mm prime over a zoom.
Where they differ
- ›Aperture: the Sigma 20mm f/2 DG DN Contemporary (L-mount) opens to f/2 vs the Sigma 18-50mm f/2.8 DC DN Contemporary (L-mount)'s f/2.8 — more light and shallower depth-of-field.
- ›Focal range: Sigma 18-50mm f/2.8 DC DN Contemporary (L-mount) is 18-50mm, Sigma 20mm f/2 DG DN Contemporary (L-mount) is 20mm — different framing and reach.
- ›Type: the Sigma 18-50mm f/2.8 DC DN Contemporary (L-mount) is a zoom (flexible framing), the Sigma 20mm f/2 DG DN Contemporary (L-mount) a prime (one focal length, usually brighter and lighter).
- ›Close-up: the Sigma 18-50mm f/2.8 DC DN Contemporary (L-mount) reaches 0.5x magnification vs 0.19x — more for close-up and macro work.
- ›Weight: the Sigma 18-50mm f/2.8 DC DN Contemporary (L-mount) is 290g (10.2 oz) vs 370g (13.1 oz) — you'll feel the difference handheld.
Frequently asked
Is the Sigma 18-50mm f/2.8 DC DN Contemporary (L-mount) or the Sigma 20mm f/2 DG DN Contemporary (L-mount) better?
The Sigma 18-50mm f/2.8 DC DN Contemporary (L-mount) is a zoom (18-50mm) and the Sigma 20mm f/2 DG DN Contemporary (L-mount) is a 20mm prime. The zoom gives you framing flexibility from one lens; the prime trades that for a fixed focal length that's usually brighter (f/2 vs f/2.8) and lighter to carry. Choose flexibility or a fast single focal length.
Who should choose the Sigma 18-50mm f/2.8 DC DN Contemporary (L-mount)?
Choose the Sigma 18-50mm f/2.8 DC DN Contemporary (L-mount) if you need more reach — it goes to 50mm vs 20mm for distant subjects, wildlife and sport. Choose it if you want one-lens flexibility — a 18-50mm zoom covers what the fixed 20mm can't reframe. Choose it if you value portability — at 290g (10.2 oz) it's lighter than the 370g (13.1 oz) alternative for travel and all-day carry. Choose it if you like close-focus work — 0.5x magnification vs 0.19x.
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 prefer a fast, compact single focal length — a 20mm prime over a zoom.
What is the main difference between the Sigma 18-50mm f/2.8 DC DN Contemporary (L-mount) and the Sigma 20mm f/2 DG DN Contemporary (L-mount)?
Aperture: the Sigma 20mm f/2 DG DN Contemporary (L-mount) opens to f/2 vs the Sigma 18-50mm f/2.8 DC DN Contemporary (L-mount)'s f/2.8 — more light and shallower depth-of-field.
| Product | ||
|---|---|---|
| Optical Design | ||
| Focal Length | 18-50mm | 20mm |
| Lens Type | Zoom | Prime |
| Optical Elements | 13 | 13 |
| Optical Groups | 10 | 11 |
| Aperture & Iris | ||
| Maximum Aperture | f/2.8 | f/2 |
| Minimum Aperture | f/22 | f/16 |
| Aperture Blades | 9 | 9 |
| Rounded Aperture | Yes | Yes |
| Coverage & Angle | ||
| Format Coverage | APS-C | Full-Frame |
| Lens Mount | L-Mount | L-Mount |
| Angle of View | 76° – 32° | 94° |
| 35mm Equivalent | 27-75mm | − |
| Focus | ||
| Autofocus | Yes | Yes |
| Focus Motor | HLA | HLA |
| Focus Limiter | No | No |
| AF/MF Switch | Yes | Yes |
| Min Focus Distance | 13 cm | 22 cm |
| Max Magnification | 0.5x | 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) | $599 | $549 |
| Filter Size | 52mm | 67mm |
| Diameter | 65.4mm | 74.8mm |
| Length | 76.9mm | 90.5mm |
| Weight | 290g (10.2 oz) | 370g (13.1 oz) |
| Weather Sealed | Yes | Yes |
| Tripod Collar | No | No |
