In 2008, Canon raised the bar on AVCHD camcorders with its HF10 and HF100. But its 2009 models, whilst remaining excellent, haven't been able to maintain the same kind of lead. Where the HF10, HF11 and HF100 provided premium quality at a relatively reasonable price, the new models have tended to either provide ultimate quality with no expense spared, such as the Legria HF S10, or to reduce features for greater affordability, such as the Legria HF20. The Legria HF21 is heir to the latter.
In keeping with Canon's numbering strategy, the HF21 is essentially an improvement on its predecessor. It's still based on the same 1/4in CMOS sensor as the HF20, which boasts a gross 3.89-megapixels. Thanks to the smaller sensor size compared to the 2008 models, a 15x optical zoom is available. The autofocus system combines both regular through-the-lens (TTL) techniques and Canon's Instant AF, which uses an external active sensor. This means the HF21 can focus even in bright or dark conditions, unlike camcorders that rely entirely on TTL.
The biggest difference compared to the earlier model is the amount of onboard storage. Instead of 32GB, you get 64GB of flash memory. Even at the top quality mode, which records at 24Mbits/sec, this is enough for six hours of footage, which will be more than sufficient for most holidays. There are four other quality modes, too. At the lowest setting, which operates at 5Mbits/sec, you can fit a whopping 24 hours of video onto the onboard memory, and there's an SDHC slot available should you need more. The top two quality modes use Full HD resolution, but the bottom three drop down to 1,440 x 1,080, like HDV. Thanks to the use of flash memory, the HF21 is surprisingly compact, too, weighing just 340g.
The HF21 offers a reasonably healthy level of features. There are mini-jacks for microphone and headphones, the latter doubling as the AV output. Manual level control is available for microphones, too. There's even an accessory shoe, protected by a plastic flap. But this is Canon's "S" Mini Advanced Shoe rather than a standard-sized one, so you will be limited to proprietary peripherals.
The icing on the cake is missing, however, as there's no lens ring available. Instead, all manual settings are configured using the controls around the LCD. On its own, the joystick accesses the quick menu system, a relatively recent addition to the interface of Canon camcorders. This provides rapid access to the most frequently-used settings such as turning on the video light and the Pre-REC function. The latter constantly spools video, which is tagged onto the beginning of the file when you hit record, so if you're slow to react you won't necessarily miss a shot.
Further functions on the quick menu include backlight compensation, the basic exposure control, and manual focusing. This calls on the joystick, which is a slightly fiddly process. But at least there's a focus assist capability to hand, which temporarily magnifies the frame for a closer look as you adjust. This is also where you gain access to the aforementioned manual audio level control, as well as the face detection system. The latter works fairly well when the faces in question are sufficiently illuminated. However, faces in deep shadow aren't easily detected, which means the system doesn't help when shooting people against a bright background.