For the past five years, my go-to wildlife lens was the Sigma 150-600mm f/5-6.3 DG OS HSM Contemporary. It accompanied me on countless early mornings and cold winter walks, capturing everything from distant birds to majestic deer in the British countryside.
In August 2025, I finally made the jump to the Canon RF 100-500mm f/4.5-7.1L IS USM. Moving to Canon’s RF system and investing in an L-series telephoto zoom felt like a big step forward in my wildlife photography. After years of shooting with the Sigma, the upgrade has been both exciting and eye-opening.
Here’s a look at why I made the switch and how the two lenses compare.
Five Years with the Sigma 150-600mm
The Sigma 150-600mm Contemporary is a lens many wildlife photographers start with, and for good reason. Its huge focal range makes it incredibly versatile for photographing distant subjects.
Over the years, it helped me photograph some of my favourite wildlife subjects:
- Red deer during autumn rutting season
- Kingfishers perched quietly along rivers
- Great crested grebes performing their elegant courtship displays
The 600 mm reach was invaluable when photographing birds that are easily disturbed or animals that keep their distance. The lens also includes optical stabilization and a Hyper Sonic Motor autofocus system designed for telephoto work.
However, after years of use, a few limitations became more apparent—particularly size, weight, and autofocus performance when adapting it to newer mirrorless bodies.
Moving to the Canon RF 100-500mm
The Canon RF 100-500mm f/4.5-7.1L IS USM is Canon’s premium super-telephoto zoom for the RF mirrorless system. Introduced alongside the EOS R-series cameras, it was designed to offer high optical performance while remaining relatively portable.
Despite losing 100 mm of reach compared to the Sigma, the Canon brings several advantages:
- Significantly lighter design
- Excellent stabilization (up to around 5 stops)
- Faster and more reliable autofocus on RF cameras
- Professional L-series build quality and weather sealing
For wildlife photography—especially birds—the improvements in autofocus and sharpness can make a noticeable difference.
Key Specification Comparison
| Feature | Sigma 150-600 Contemporary | Canon RF 100-500L |
|---|---|---|
| Focal length | 150–600 mm | 100–500 mm |
| Maximum aperture | f/5–6.3 | f/4.5–7.1 |
| Optical design | 20 elements in 14 groups | 20 elements in 14 groups |
| Minimum focus distance | 2.8 m | 0.9 m (at 100 mm) |
| Max magnification | 0.20× | 0.33× |
| Weight | ~1,830–1,930 g | ~1,365–1,370 g |
| Filter size | 95 mm | 77 mm |
The biggest differences I notice in practice are weight, focusing accuracy, and handling.
Real-World Differences in the Field
1. Weight and Handling
The Sigma weighs close to 2 kg, which becomes noticeable after a long day in the field.
The Canon, at roughly 1.37 kg, feels dramatically lighter.
This makes handheld shooting—especially tracking birds like kingfishers or grebes—much more comfortable.
2. Autofocus Performance
On mirrorless cameras, the Canon lens feels noticeably faster and more precise.
Tracking fast-moving wildlife such as birds in flight or diving grebes benefits greatly from modern RF autofocus systems.
3. Sharpness and Image Quality
While the Sigma performs well, the Canon delivers consistently sharp images across the frame, especially toward the long end of the zoom range.
When photographing small birds like kingfishers, that extra detail in the feathers really stands out.
4. Close Focusing
One surprising benefit of the Canon is its much shorter minimum focus distance (0.9 m) compared to the Sigma’s 2.8 m.
This opens up opportunities for near-macro wildlife shots, such as birds perched close to a hide.
Do I Miss the 600 mm?
Sometimes.
For distant wildlife—especially small birds—600 mm is undeniably useful. However, the improved sharpness of the Canon means that cropping images often compensates for the missing 100 mm.
And in many situations, 500 mm is already plenty of reach.
Final Thoughts
The Sigma 150-600mm f/5-6.3 DG OS HSM Contemporary served me incredibly well for five years and remains one of the best value wildlife lenses available.
But upgrading to the Canon RF 100-500mm f/4.5-7.1L IS USM has been a meaningful step forward. The lighter weight, improved autofocus, and excellent optical performance make it a fantastic companion for photographing wildlife—whether that’s red deer at dawn, a kingfisher along the riverbank, or great crested grebes dancing across the water.
For me, it feels like the start of a new chapter in my wildlife photography.
FAQ
Yes. Its fast autofocus, strong image stabilisation, and excellent sharpness make it one of the best RF lenses for wildlife and bird photography.
In most situations yes, especially when combined with high-resolution mirrorless cameras that allow cropping and cameras with APS-C sized sensors .
Absolutely. It remains one of the best value long-reach wildlife lenses available.
