Further enhancements have been made to the stabilisation modes. Like many other manufacturers, Canon has added more powerful image stabilisation on top of the standard implementation. The Dynamic mode improves slow shaking, whilst the Powered mode does a better job when the vibrations are more violent. Strangely, unlike Panasonic's new stabilisation system, the most powerful option isn't always the best overall, since the Powered mode is not as good as the Dynamic one for mild undulations.
All the usual enthusiast features are present and correct, including minijacks for headphones and an external microphone. However, whilst an accessory shoe lurks under a sliding door, this is Canon's "S" Mini Advanced Shoe, so won't accept standard peripherals. The Legria HF S21 is quite a large camcorder in its class, weighing 100g more and measuring 10mm extra in each dimension compared to Panasonic's HDC-TM700. This doesn't make it any less comfortable to use, but we'd recommend using a dedicated camcorder bag rather than stuffing it into a general one.
Although it has the same sensor and image processing engine as the Legria HF S10, the HF S21 shows slight improvements in image quality. In the best lighting, there's no discernible difference, and performance is equal to or better than any other consumer camcorder currently available. But the image looks marginally brighter in low light compared to the previous model. The picture is still slightly darker than some competitors, in particular Panasonic's HDC-TM700 and JVC's Everio GZ-HM1. However, the HF S21's 25PF mode allows the shutter to drop to 1/25th even in auto mode, for a noticeably brighter image than the competition, with no sign of extra grain.
Fortunately, the most important thing the Canon Legria HF S21 doesn't have in common with the HF S10, at launch, is price. It's still on the costly side, coming in at around a grand. But this is much closer to the competition, making the HF S21 a much keener option. Whilst we'd still opt for Panasonic's HDC-TM700 due to its exceptional manual control, thanks to its lens ring, the HF S21 comes close in most other respects.