Sony HDR-CX7 Camcorder Review
Of the multitude of high definition camcorders Sony has released this year, the HDR-CX7 is undoubtedly the most fetching to the eye. Gone are cumbersome, bulky elements like a tape deck, DVD bay, or a lot of on-board ports and jacks. The problem with throwing out the bath water, of course, is keeping hold of the baby. Unlike its sibling camcorders, the HDR-CX7 lacks a lot of manual control features and interfaces like the control dial that helps justify the big price tag. The result is a very pricey point-and-shoot that looks cool and shoots well in adequate lighting, but could use a bit more horsepower in some key areas.
Video Performance* (9.0)*
The Sony HDR-CX7 comes equipped with a 1/2.9-inch CMOS sensor. This is the same chip found on nearly all of its top-tier HD camcorders this year, including the HDR-HC7, HDR-UX7, and HDR-SR7. The HDR-CX7’s chip has a gross pixel count of 3,200,000 (with an effective pixel count of 2,280,000 in 16:9 aspect ratio; 1,710,000 effective pixels in 4:3 aspect ratio).
First, we’ll look at the standardized testing. We shot a DSC Labs Chroma DuMonde Color Checker chart at an even 3000 lux and compared the results to the competition to see how it fared. Under these conditions, the color performance was as good as we’d hoped. The camcorder presented a nice, balanced spectrum. It pushed the saturation past the point where pro camcorders would have stopped, but really hit a sweet spot for a consumer camcorder. As usual with Sonys, the greens pop with a particular vivacity. Sony seemed comfortable relying on the high pixel count to produce a satisfactory sharpness, as the oversharpening was not too noticeable. Extreme zooms revealed that the blacks would bottom out along high contrast areas. To Sony’s credit, however, none of the whites blew out.
By comparison, the HDR-HC7, with its kinder, gentler HDV compression, still looked better. A close up look of the results side-by-side reveal that the HDR-CX7 lacks the fine detail retention of the HC7. Last year’s HDR-SR1, its first HDD AVCHD camcorder, had similar color performance and sharpness.
|*Above, the Sony HDR-HC7 Below, the Sony HDR-CX7*|
The closest competitor to the HDR-CX7 is the Panasonic HDC-SD1, which also records AVCHD video to a flash memory card. The SD1 features three 1/4-inch CCDs and produces a radically different color, much less saturated than Sony’s. In our Great HD Shootout, the Panasonic HDC-SD1 produced the second-best color in bright light after the Canon HV20. Overall, however, the Sony image looked much sharper. The SD1 produced a soft, almost out of focus look caused by a double assault of noise and compression artifacting. Overall, we have to put this particular battle in Sony’s favor. Panasonic has since announced the HDC-SD5 as a replacement, though that camcorder was not available at the time of this review.
Another major competitor is the Canon HG10, an AVCHD camcorder recording to hard drive. The HG10 blew us away as the best performing AVCHD model we’ve seen to date. In bright light, the image is virtually noise-free, and managed to produced the best color of any AVCHD camcorder. This was not surprising given that it shares the same imager as the Canon HV20 (the HDV camcorder we’ve been singing the praises of for months). In pretty much every regard of performance, it tops the CX7.
The Sony HDR-CX7 is also one of the few to offer shooting in the new-ish xvYCC color space, which Sony (true to form) has embraced and re-branded as their own "x.v. Color." xvYCC color space is reportedly up to 1.8 times the color gamut of sRGB, which is used on most flat panel TVs. We, like 99.9 percent of the population, do not own a TV that can play back in "x.v. Color," and can only speculate on its effectiveness. When we saw the display on an actual xvYCC monitor at CES in January, the image appeared to the naked eye as little more than a saturated sRGB image. Shooting in the "x.v. Color" mode on the HDR-CX7 showed about the same results: a more saturated image.
In the course of our practical shooting, we found several faults with the Sony HDR-CX7’s performance. In environments where the light temperature is fairly consistent, like outdoors on a sunny day or indoors under incandescent or fluorescent lighting, the color balance is fine. However, under mixed lighting (i.e. indoor fluorescent lighting with sunny windows), the camcorder cannot auto correct and the colors look abysmal. Not having a white card handy for a manual white balance will be a problem.
The problem, which we’ll get into in more depth later, was the auto focus. The HDR-CX7 could not seem make minor focus corrections with the speed you should expect in a $1,000-plus camcorder. A subject shifting back and forth and few inches, for example, would constantly be out of focus. We found this to be unacceptable, particularly because the manual focus control is so poor.
On the plus side, the HDR-CX7 did not show many signs of motion artifacting, which is a big stride in AVCHD compression. Panasonic’s HDC-SD1 had an intolerable amount, creating motion trails with the slightest shake. Last year’s first-generation AVCHD camcorders from Sony looked noisy under even the best lighting, and some of that was the result of compression artifacting. While the motion rendering did not look as good as HDV compression, all the Sonys have thus far looked better than the Panasonics.
Video Resolution (17.25)
We tested the Sony HDR-CX7 by shooting a DSC Labs video resolution chart, then reading the results from playback footage on an HD monitor. We found the camcorder was able to produce an approximate horizontal resolution of 600 line widths per picture height (lw/ph) and a vertical resolution of 575 lw/ph. This compared well to other HD camcorders, but slightly lower than the Sony HDR-HC7 and Canon HG10.
Low Light Performance* (3.51)*
Low light testing has a number of components. First, the camcorder is turned on a DSC Labs Chroma DuMonde color chip chart at 60 lux and 15 lux, then held up against the competition. At 60 lux, the Sony HDR-CX7 looked rather good. The large 1/2.9-inch CMOS chip was able to retain a lot of light. Unfortunately, it also produced a lot of fine grain noise. This much noise in a standard definition image would have been seriously detrimental to fine detail resolution. But because high definition is so, well… high in its definition, the fine-grain noise didn’t have much of an adverse effect in that regard. Blown up on a big screen TV, you’ll definitely see a lot of dancing pixels in the shadows, so be prepared.
In bright light testing, we saw a sizeable performance gap between the Sony HDR-CX7 and the HDR-HC7, which won out with its preferable HDV compression. At 60 lux, that gap decreased to put the camcorders neck-and-neck with each other. The color performance and apparent brightness were indistinguishable. The HDR-HC7 still has a sharper image, but only slightly. This seems to be due to the fact that the low light makes some of the CX7’s compression artifacts less noticeable.
Under the same 60 lux lighting, the Panasonic HDC-SD1 actually produced a brighter image. Again, the color performance was not as saturated, emulating a slightly more pro look. However, like in bright light, the image was had an overall fuzzy look. It was also terrible in motion, creating a lot of artifacting. We preferred the HDR-CX7.
The Canon HG10 produced a picture with just about the same amount of color retention, but a world of difference in noise reduction. Compared to the HG10, the HDR-CX7 looks much, much grainier.
At 15 lux, the Sony HDR-CX7 lost most of its color. What color there was became marred, as the camcorder could not take a manual white balance under such low lighting. This is not surprising, as nearly all camcorders fail in the 15 lux test. We just like to watch them fall. The Sony HDR-HC7 was brighter and more accurate, but had so much noise that a lot of fine detail was sacrificed. The Panasonic HDC-SD1 produced the most accurate colors, though the soft look of the video was once again the biggest failing. The Canon HG10 was the best performer in 15 lux, but it too was marred by a lot of noise.
The second part of our low light testing involves shooting a GretagMacBeth Color Checker chart at 60 lux, then running frames through Imatest to determine color accuracy, noise, and saturation levels. At best, the Sony HDR-CX7 was able to produce a color error of 13.2. This is rather high, but the results indicated that the error lay more in the in-camera saturation than errors caused by low light. Other camcorders with similarly saturated images produced an equivalent score, yet managed to look good otherwise in low light. According to Imatest, the saturation level was 75.08 percent. The noise was approximately 1.35 percent. This is higher than some others, but not bad overall. As we said, you can see the noise quite clearly with your own eyes.
The third segment determines sensitivity. We slowly and steadily drop the light levels, watching IRE levels on a waveform monitor, until the camcorder is peaking 50 IRE. These are areas where some level of fine detail could still be seen by the eye. At best, the Sony HDR-CX7 was able to produce a peak 50 IRE at 17 lux. This was not nearly as good as the HDR-HC7, which could do the same with only 7 lux of light. Since the imager is the same, even given manufacturing variances, the loss of sensitivity must be caused by the compression.
We tested the effectiveness of the HDR-CX7’s Super SteadyShot OIS by using our custom built shake emulator, crafted exclusively for CamcorderInfo.com. The camcorder was set to full Auto mode with the LCD flipped open in order to simulate a typical recording position. The HDR-CX7 was tested at two speeds. Speed one is akin to a casual stroll down the sidewalk. Speed two is more along the lines of a hasty jog or rickety car ride. The HDR-CX7 produced a 61.2 percent shake reduction at speed one, however, failed to produce any change at speed two. Given the camcorder’s size and weight, this makes sense. These results prove it will be difficult to control fast motion, with or without Super SteadyShot.
Wide Angle (9.4)
We tested the HDR-CX7’s maximum field of view by measuring the left and right angles with a vertical laser. The camcorder was set to full Auto mode with Super SteadyShot disabled and the LCD flipped open. After subtracting the differences of both angle measurements viewed on a native monitor, we found the HDR-CX7’s maximum field of view to be 47 degrees, which is on the higher end.
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