Canon RF Lens 100-400mm F5.6-8 IS USM - Telephoto Zoom Camera Lens with 5.5-stop vs Canon RF-S Lens 18-150mm F3.5-6.3 IS STM - Zoom Camera Lens with 4.5-stop Optica

Price and Value Comparison

The Canon RF-S Lens 18-150mm F3.5-6.3 IS STM is £50 cheaper than the Canon RF Lens 100-400mm F5.6-8 IS USM, representing about 8.4% savings at current pricing. At £549.00, it offers a more accessible entry point into Canon’s RF-S system, especially considering its average price over the past 30 days was just £508.44—nearly £40 below the current rate of the longer telephoto lens. While the 100-400mm lens commands a premium at £599.00, this reflects its extended reach and advanced optical features, which are not present in the shorter zoom range. The lower price of the 18-150mm model makes it a compelling choice for budget-conscious photographers seeking versatility without breaking the bank.

Zoom Range and Versatility

The Canon RF Lens 100-400mm F5.6-8 IS USM provides a far greater telephoto reach, covering a 100-400mm range ideal for capturing distant subjects like wildlife or sporting events. This makes it significantly more powerful for specialized long-distance photography compared to the Canon RF-S Lens 18-150mm F3.5-6.3 IS STM, which spans a more general-purpose 18-150mm range. The 100-400mm lens effectively extends your ability to frame subjects from afar, offering true super telephoto capability. In contrast, the 18-150mm lens excels as a compact all-rounder, suitable for everyday shooting, travel, and vlogging, but lacks the extreme reach needed for professional-level wildlife or sports imaging.

Image Stabilisation Performance

Both lenses feature optical image stabilisation, but the Canon RF Lens 100-400mm F5.6-8 IS USM boasts a superior 5.5-stop stabilisation system, outperforming the 4.5-stop stabiliser in the Canon RF-S Lens 18-150mm F3.5-6.3 IS STM by one full stop. This extra stability is crucial when shooting handheld at longer focal lengths, particularly in low-light conditions or during video capture. The 5.5-stop advantage translates directly into sharper images and smoother footage at slower shutter speeds, giving the 100-400mm lens an edge in challenging shooting environments. For users prioritising maximum stability across the entire zoom range, the 100-400mm lens delivers measurable performance benefits.

Autofocus and Focus Smoothness

The Canon RF Lens 100-400mm F5.6-8 IS USM utilises a USM (Ultra Sonic Motor) autofocus system, known for fast, quiet, and precise focusing—ideal for tracking moving subjects in sports or wildlife photography. In contrast, the Canon RF-S Lens 18-150mm F3.5-6.3 IS STM relies on a quieter STM (Stepping Motor) system, which is also smooth and silent but typically designed for video and lighter-duty applications. While both systems ensure responsive performance, the USM motor in the 100-400mm lens is better suited to high-speed action, where rapid focus adjustments are critical. The STM motor in the 18-150mm lens still delivers reliable results but may lag slightly in demanding scenarios involving fast-moving targets.

Build Quality and Portability

The Canon RF Lens 100-400mm F5.6-8 IS USM is described as lightweight and compact at just 635g and 164.7mm in length, making it highly portable despite its extensive zoom range. However, the Canon RF-S Lens 18-150mm F3.5-6.3 IS STM is explicitly noted for its even more compact size, allowing it to stay mounted on the camera all day or fit easily into a kit bag. This design philosophy prioritizes convenience and constant readiness, especially for travel or daily use. While both lenses are practical for on-the-go photography, the 18-150mm model’s emphasis on portability gives it a slight edge in everyday usability, particularly for users who value minimal gear burden.

Compatibility and Camera Fit

The Canon RF Lens 100-400mm F5.6-8 IS USM is compatible with any Canon EOS R System camera, ensuring broad interoperability across full-frame models. In contrast, the Canon RF-S Lens 18-150mm F3.5-6.3 IS STM is specifically designed for APS-C sensor cameras within the EOS R System—including models like the R100, R50, R10, R6, R7, and R8. This limitation means it cannot be used on full-frame EOS R bodies without potential vignetting or reduced performance. Users with full-frame cameras should opt for the 100-400mm lens to avoid compatibility issues. Conversely, those using APS-C cameras will find the RF-S lens perfectly tailored to their system, delivering optimal image quality and coverage.

Which should you buy?

If you need serious telephoto reach for wildlife, sports, or distant landscapes, the Canon RF Lens 100-400mm F5.6-8 IS USM is the clear winner—despite being £50 more expensive at £599.00. Its 5.5-stop image stabilisation, USM autofocus, and 100-400mm range provide unmatched power and precision. However, if you're using an APS-C camera and want a versatile, compact lens for travel, vlogging, or everyday shooting, the Canon RF-S Lens 18-150mm F3.5-6.3 IS STM at £549.00 offers excellent value—especially given its bestseller rank of 40. It’s 17% cheaper than the 100-400mm lens on average and fits seamlessly into daily use. Choose based on your camera body and shooting needs: full-frame or extreme reach? Go for the 100-400mm. APS-C and portability? The 18-150mm delivers smarter bang for buck.