Sigma 17mm f/4 DG DN Contemporary (L-mount) vs Sigma 18-50mm f/2.8 DC DN Contemporary (L-mount)
The bottom line
These cover different focal lengths — the Sigma 17mm f/4 DG DN Contemporary (L-mount) is 17mm, the Sigma 18-50mm f/2.8 DC DN Contemporary (L-mount) is 18-50mm — so they're not really substitutes. Pick by the field of view you actually need: the Sigma 17mm f/4 DG DN Contemporary (L-mount) for wide-angle, the Sigma 18-50mm f/2.8 DC DN Contemporary (L-mount) for standard zoom.
Choose the Sigma 17mm f/4 DG DN Contemporary (L-mount) if…
- ✓You prefer a fast, compact single focal length — a 17mm prime over a zoom.
- ✓You value portability — at 225g (7.9 oz) it's lighter than the 290g (10.2 oz) alternative for travel and all-day carry.
Choose the Sigma 18-50mm f/2.8 DC DN Contemporary (L-mount) if…
- ✓You want more light and background blur — f/2.8 is faster than f/4, better for low light and subject separation.
- ✓You need more reach — it goes to 50mm vs 17mm for distant subjects, wildlife and sport.
- ✓You want one-lens flexibility — a 18-50mm zoom covers what the fixed 17mm can't reframe.
- ✓You work outdoors — it's weather-sealed against dust and moisture; the other isn't.
Where they differ
- ›Aperture: the Sigma 18-50mm f/2.8 DC DN Contemporary (L-mount) opens to f/2.8 vs the Sigma 17mm f/4 DG DN Contemporary (L-mount)'s f/4 — more light and shallower depth-of-field.
- ›Focal range: Sigma 17mm f/4 DG DN Contemporary (L-mount) is 17mm, Sigma 18-50mm f/2.8 DC DN Contemporary (L-mount) is 18-50mm — different framing and reach.
- ›Type: the Sigma 18-50mm f/2.8 DC DN Contemporary (L-mount) is a zoom (flexible framing), the Sigma 17mm f/4 DG DN Contemporary (L-mount) a prime (one focal length, usually brighter and lighter).
- ›Durability: the Sigma 18-50mm f/2.8 DC DN Contemporary (L-mount) is weather-sealed; the other isn't.
Frequently asked
Is the Sigma 17mm f/4 DG DN Contemporary (L-mount) or the Sigma 18-50mm f/2.8 DC DN Contemporary (L-mount) better?
These cover different focal lengths — the Sigma 17mm f/4 DG DN Contemporary (L-mount) is 17mm, the Sigma 18-50mm f/2.8 DC DN Contemporary (L-mount) is 18-50mm — so they're not really substitutes. Pick by the field of view you actually need: the Sigma 17mm f/4 DG DN Contemporary (L-mount) for wide-angle, the Sigma 18-50mm f/2.8 DC DN Contemporary (L-mount) for standard zoom.
Who should choose the Sigma 17mm f/4 DG DN Contemporary (L-mount)?
Choose the Sigma 17mm f/4 DG DN Contemporary (L-mount) if you prefer a fast, compact single focal length — a 17mm prime over a zoom. Choose it if you value portability — at 225g (7.9 oz) it's lighter than the 290g (10.2 oz) alternative for travel and all-day carry.
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 want more light and background blur — f/2.8 is faster than f/4, better for low light and subject separation. Choose it if you need more reach — it goes to 50mm vs 17mm for distant subjects, wildlife and sport. Choose it if you want one-lens flexibility — a 18-50mm zoom covers what the fixed 17mm can't reframe. Choose it if you work outdoors — it's weather-sealed against dust and moisture; the other isn't.
What is the main difference between the Sigma 17mm f/4 DG DN Contemporary (L-mount) and the Sigma 18-50mm f/2.8 DC DN Contemporary (L-mount)?
Aperture: the Sigma 18-50mm f/2.8 DC DN Contemporary (L-mount) opens to f/2.8 vs the Sigma 17mm f/4 DG DN Contemporary (L-mount)'s f/4 — more light and shallower depth-of-field.
| Product | ||
|---|---|---|
| Optical Design | ||
| Focal Length | 17mm | 18-50mm |
| Lens Type | Prime | Zoom |
| Optical Elements | 10 | 13 |
| Optical Groups | 8 | 10 |
| Aperture & Iris | ||
| Maximum Aperture | f/4 | f/2.8 |
| Minimum Aperture | f/22 | f/22 |
| Aperture Blades | 9 | 9 |
| Rounded Aperture | Yes | Yes |
| Coverage & Angle | ||
| Format Coverage | Full-Frame | APS-C |
| Lens Mount | L-Mount | L-Mount |
| Angle of View | 104° | 76° – 32° |
| 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 | 13 cm |
| Max Magnification | 0.5x | 0.5x |
| 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 | 55mm | 52mm |
| Diameter | 62mm | 65.4mm |
| Length | 61.4mm | 76.9mm |
| Weight | 225g (7.9 oz) | 290g (10.2 oz) |
| Weather Sealed | No | Yes |
| Tripod Collar | No | No |
