Canon RF100-400mm F5.6-8 IS USM Lens
The Canon 100-400mm f/5.6-8 IS USM is a 100–400mm f/5.6 lens designed for Canon RF mount cameras. Check GearFocus for current availability, with buyer protection on every purchase.

Canon RF100-400mm F5.6-8 IS USM Lens
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Lens Overview — Canon 100-400mm f/5.6-8 IS USM
Key Features — Canon 100-400mm f/5.6-8 IS USM
100–400mm Telephoto Zoom: Covers a wide range of telephoto focal lengths suitable for wildlife, sports, and distant subjects in a single lens.
Variable f/5.6–8 Aperture: Maximum aperture shifts from f/5.6 at 100mm to f/8 at 400mm, a trade-off that enables the lens's compact size and light weight.
Built-In Optical Stabilization: Optical image stabilization reduces the effect of camera shake, supporting sharper handheld results at longer focal lengths.
Lightweight 635g Build: At 635 grams, this is an unusually portable lens for its focal length range, suited to travel, hiking, and extended handheld shooting.
Canon RF Mount: Designed exclusively for Canon's RF mirrorless system, with full compatibility across Canon's full-frame and APS-C RF-mount camera bodies.
USM Autofocus Motor: Ultrasonic motor delivers fast, quiet autofocus performance well-suited to tracking moving subjects like birds and athletes.
Lens Specifications — Canon 100-400mm f/5.6-8 IS USM
| Spec | Detail |
|---|---|
| Use Cases | Wildlife, Sports, Travel, Birding |
| Lens Type | Zoom |
| Format | Full Frame |
| Zoom/Prime | Zoom |
| Focal Length | 100–400mm |
| Maximum Aperture | f/5.6 |
| Camera System | Mirrorless |
| Lens Mount | Canon RF |
| Autofocus | Yes |
| Focus Type | Auto, Manual |
| Image Stabilization | Optical |
| Filter Thread | 67mm |
Description — Canon 100-400mm f/5.6-8 IS USM
The Canon RF 100-400mm f/5.6-8 IS USM is a telephoto zoom lens designed for the Canon RF mirrorless system, covering a full-frame image circle. Its focal length spans 100mm to 400mm, giving photographers substantial reach for distant subjects across a range of scenarios. The variable maximum aperture opens to f/5.6 at the wide end and f/8 at full telephoto, a reasonable trade-off for the lens's compact and portable build.
Weighing in at just 635g, it stands out as a lightweight option in the telephoto zoom category, reducing fatigue during handheld or travel shooting. Optical image stabilization is integrated into the lens to help counteract camera shake. Both autofocus and manual focus are supported, giving shooters control over how they engage with their subjects. A 67mm filter thread makes it straightforward to use popular filter types without needing large, expensive accessories.
Built exclusively for the Canon RF mount, it integrates natively with Canon's range of RF-mount mirrorless cameras.
Pros — Canon 100-400mm f/5.6-8 IS USM
- ✓Broad 100–400mm focal length range covers a wide variety of telephoto shooting scenarios
- ✓Lightweight at just 635g, making it practical for handheld and travel use
- ✓Built-in optical image stabilization helps manage camera shake
Cons — Canon 100-400mm f/5.6-8 IS USM
- ✗Variable maximum aperture of f/5.6–f/8 limits light intake, especially at longer focal lengths
- ✗f/8 maximum aperture at 400mm may challenge autofocus performance in lower light
- ✗Designed solely for Canon RF mount, limiting compatibility to that specific system
Reviews — Canon 100-400mm f/5.6-8 IS USM
Videos — Canon 100-400mm f/5.6-8 IS USM
Canon’s CHEAPEST RF ZOOM Lens: 100-400mm f5.6-8 IS Review…is it worth it? — Jared Polin