Sigma 15mm F1.4 DC Contemporary (Canon RF) vs Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD (Canon RF)
The bottom line
These cover different focal lengths — the Sigma 15mm F1.4 DC Contemporary (Canon RF) is 15mm, the Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD (Canon RF) is 18-300mm — so they're not really substitutes. Pick by the field of view you actually need: the Sigma 15mm F1.4 DC Contemporary (Canon RF) for wide-angle, the Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD (Canon RF) for super-telephoto.
Choose the Sigma 15mm F1.4 DC Contemporary (Canon RF) if…
- ✓You want more light and background blur — f/1.4 is faster than f/3.5, better for low light and subject separation.
- ✓You prefer a fast, compact single focal length — a 15mm prime over a zoom.
- ✓You value portability — at 220g (7.8 oz) it's lighter than the 620g (1.37 lb) alternative for travel and all-day carry.
Choose the Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD (Canon RF) if…
- ✓You need more reach — it goes to 300mm vs 15mm for distant subjects, wildlife and sport.
- ✓You want one-lens flexibility — a 18-300mm zoom covers what the fixed 15mm can't reframe.
- ✓You shoot handheld or on an unstabilised body — it has optical stabilisation, the other doesn't.
- ✓You like close-focus work — 0.5x magnification vs 0.15x.
Where they differ
- ›Aperture: the Sigma 15mm F1.4 DC Contemporary (Canon RF) opens to f/1.4 vs the Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD (Canon RF)'s f/3.5 — more light and shallower depth-of-field.
- ›Focal range: Sigma 15mm F1.4 DC Contemporary (Canon RF) is 15mm, Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD (Canon RF) is 18-300mm — different framing and reach.
- ›Type: the Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD (Canon RF) is a zoom (flexible framing), the Sigma 15mm F1.4 DC Contemporary (Canon RF) a prime (one focal length, usually brighter and lighter).
- ›Stabilisation: only the Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD (Canon RF) has optical stabilisation — steadier handheld shots, especially on bodies without IBIS.
- ›Close-up: the Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD (Canon RF) reaches 0.5x magnification vs 0.15x — more for close-up and macro work.
- ›Weight: the Sigma 15mm F1.4 DC Contemporary (Canon RF) is 220g (7.8 oz) vs 620g (1.37 lb) — you'll feel the difference handheld.
Frequently asked
Is the Sigma 15mm F1.4 DC Contemporary (Canon RF) or the Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD (Canon RF) better?
These cover different focal lengths — the Sigma 15mm F1.4 DC Contemporary (Canon RF) is 15mm, the Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD (Canon RF) is 18-300mm — so they're not really substitutes. Pick by the field of view you actually need: the Sigma 15mm F1.4 DC Contemporary (Canon RF) for wide-angle, the Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD (Canon RF) for super-telephoto.
Who should choose the Sigma 15mm F1.4 DC Contemporary (Canon RF)?
Choose the Sigma 15mm F1.4 DC Contemporary (Canon RF) if you want more light and background blur — f/1.4 is faster than f/3.5, better for low light and subject separation. Choose it if you prefer a fast, compact single focal length — a 15mm prime over a zoom. Choose it if you value portability — at 220g (7.8 oz) it's lighter than the 620g (1.37 lb) alternative for travel and all-day carry.
Who should choose the Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD (Canon RF)?
Choose the Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD (Canon RF) if you need more reach — it goes to 300mm vs 15mm for distant subjects, wildlife and sport. Choose it if you want one-lens flexibility — a 18-300mm zoom covers what the fixed 15mm can't reframe. Choose it if you shoot handheld or on an unstabilised body — it has optical stabilisation, the other doesn't. Choose it if you like close-focus work — 0.5x magnification vs 0.15x.
What is the main difference between the Sigma 15mm F1.4 DC Contemporary (Canon RF) and the Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD (Canon RF)?
Aperture: the Sigma 15mm F1.4 DC Contemporary (Canon RF) opens to f/1.4 vs the Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD (Canon RF)'s f/3.5 — more light and shallower depth-of-field.
| Product | ||
|---|---|---|
| Optical Design | ||
| Focal Length | 15mm | 18-300mm |
| Lens Type | Prime | Zoom |
| Optical Elements | 13 | 19 |
| Optical Groups | 11 | 15 |
| Aperture & Iris | ||
| Maximum Aperture | f/1.4 | f/3.5 |
| Minimum Aperture | f/16 | f/22 |
| Aperture Blades | 9 | 9 |
| Rounded Aperture | Yes | Yes |
| Coverage & Angle | ||
| Format Coverage | APS-C | APS-C |
| Lens Mount | Canon RF | Canon RF |
| Angle of View | 82.9° | 76° – 5.2° |
| 35mm Equivalent | 24-24mm | 29-480mm |
| Focus | ||
| Autofocus | Yes | Yes |
| Focus Motor | HLA | VXD |
| Focus Limiter | No | No |
| AF/MF Switch | Yes | No |
| Min Focus Distance | 18 cm | 15 cm |
| Max Magnification | 0.15x | 0.5x |
| Stabilization & Video | ||
| Optical Stabilization | No | Yes |
| Aperture Ring | Yes | No |
| Declickable Aperture | Yes | No |
| Parfocal | No | No |
| Internal Zoom | No | No |
| General | ||
| Price (MSRP) | $579 | $629 |
| Filter Size | 58mm | 67mm |
| Diameter | 64mm | 75.5mm |
| Length | 65mm | 123.6mm |
| Weight | 220g (7.8 oz) | 620g (1.37 lb) |
| Weather Sealed | Yes | Yes |
| Tripod Collar | No | No |
