The HF M40 uses the same CMOS Pro sensor found in the more expensive HF G10, but it's paired with a smaller, less expensive lens.
Overall, the camcorder's video looks relatively sharp — and, like most, looks even better when played directly on a TV. There is some aliasing on edges, generally as a result of the interlaced video format; one difference between the M40 and its step-up G10 sibling is the lack of a native 1080 progressive encoding format.
Exposure and colour-rendering look very good, with a broad tonal range — there's no excessive clipping in the highlights or the shadows. Though the M40 uses the same sensor as the more expensive HF G10, the lenses are very different, and it shows in a variety of ways. In this case, the more pentagonal aperture renders less pleasing out-of-focus highlights. That probably won't matter to most potential users of this model, but it will influence those seeking a more artistic look.
It meters and exposes correctly and consistently most of the time, but, like many camcorders, tends to underexpose in situations where there's not necessarily backlighting, but rather a large subject surrounded by a lot of ambient light (think of a flag waving against a blue sky).
The image stabilisation is solid; the Dynamic setting works well up to about 75 per cent of the way through the focal range and Powered IS is rock-steady at maximum telephoto. It focuses quickly, though you can somewhat adjust how gradually that happens (Instant and Normal). The autofocus works well, but not significantly better than we've seen in previous models, and, like all camcorders, it can inappropriately lock onto the background instead of the subject. Zooming feels smooth and it's easy to keep it at a consistent rate.
The camcorder's low-light video (about 17 lux) looks quite good; a little soft, but with a nice balance between sharpness and colour saturation, and accuracy in its noise reduction. Lower light — dim living-room quality — displays more softness and colour noise, but we think most people would consider it acceptable.