Sony HDR-CX7

Video Performance
The Sony HDR-CX7 is outfitted with Sony’s top-end ClearVID CMOS sensor measuring a generous 1/2.9" with a gross pixel count of 3,200,000 pixels and an effective pixel count of 2,280,000. Although we won’t get this camcorder into the lab for another few months, we can make an educated guess about how it will perform from what we know about the company’s other AVCHD camcorders and the HDR-HC7. We tested the HC7 earlier this year, and that HDV camcorder is equipped with the same 1/2.9" CMOS sensor.

In a nutshell, we expect the CX7 to exhibit video performance similar to that of the HC7, but exhibiting the idiosyncrasies of AVCHD compression. The HDR-HC7 carried the company’s CMOS technology further, with higher resolution and colors that truly pop. Sony always delivers a colorful, attractive image catered to the tastes of consumer shooters who want their video to look rich, and in general respects, the CX7 should present the same oversaturation. We also anticipate a very sharp picture, and the HC7 turned in a resolution score virtually identical to this year’s other HDV standout, Canon’s HV20. Due to the aggressiveness of AVCHD compression, the CX7 may show a slight drop in video resolution, but we would expect the difference to be negligible.

The most obvious negative characteristics of AVCHD video is how it treats motion. Last year’s Sony HDR-SR1 and Panasonic’s HDC-SD1 both showed image trailing that is much more prominent than in other compression types. While this effect is subtle, it is something to be aware of – and to look for – if you find yourself giving any AVCHD camcorder a test drive. AVCHD also tends to be a bit noisier than HDV, and that noise is more severe in low light. Despite these caveats about AVCHD, it is still an impressive technology, and the HDR-CX7 should deliver video performance that is close to that of its HDV sibling.

Low Light Performance
Last year’s 1/3" ClearVID CMOS Sonys including the HDR-HC3 performed well in low light, but the HDR-HC7 (1/2.9' CMOS) actually showed a drop in low light video quality. This likely stems from the increase in pixel count over last year’s 1/3" CMOS sensors, from roughly 2,100,000 pixels to 3,200,000 pixels. This means there are over a million more pixels packed into the nearly the same space. In general, a smaller pixel gathers less light than a larger one. Given this, we expect to see a similar low light performance drop in the SR7 over last year’s SR1, which used the lower-resolution sensor found on the HC3.

The most notable deficit we saw in the HC7’s low light footage was noise – and lots of it. In order to compensate for the lesser light-gathering ability of the new, higher-resolution sensor, Sony seems to have pumped up the gain. It’s unclear at this stage exactly how AVCHD compression will deal with higher gain levels on the SR7, but the inherently higher noise levels of AVCHD may compound the issue. Without manual shutter speed control, compensating for low light must be left to either of two AE modes: Color Slow Shutter, which lowers the shutter speed to 1/30 in low light, or Super NightShot mode, which automatically lowers the shutter speed as low as 1/4.