JVC GZ-MG255 Camcorder Reviewby Michael PerlmanPublished on Aug 16, 2007 4:00 PM 
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Video Performance (5.25)
The JVC GZ-MG255 (Review, Specs, $457.00) features a single CCD imager measuring 1/3.9-inches, with a gross pixel count of 2,180,000 (the manual does not state the effective pixel count). It appears to be the same CCD found in last year’s JVC GZ-MG77 (Review, Specs, $467.95). An imager this large and dense in pixels sets a relatively high bar for itself in terms of image quality.
To start, we shot our trusty DSC Labs Chroma DuMonde color chip chart at an even 3000 lux. The image gives us data about color performance and apparent sharpness. Looking at the results, the GZ-MG255 had the same tonal response as last year’s MG77. While the colors are highly saturated, they’re not as bad as we have seen on some of the poorer HDD camcorders, which can appear neon in the most extreme cases. These are colors that will no doubt “pop” on your TV, but they’re far from a pro camcorder’s responses.
These shots were recorded after a manual white balance, which we highly recommend. The JVC Everios we’ve seen this year all have a tendency to push the auto white balance too warm. In strong sunlight, this can help compensate for blue overtones, but indoors it can make your subjects appear orange.
The fine detail capture was not great, considering the size of the imager, but the performance was passable. More technical data regarding resolution is described in the next section.
The GZ-MG555 (Review, Specs, $626), the next model up from JVC, has a larger CCD (1/2.5-inches) that produced more accurate color but did little to increase the apparent resolution. The Hitachi DZ-HS300A (Review, Specs, $0) showed much bolder and less accurate colors, and could not match the JVC for sharpness.
Out of the lab, the performance of the GZ-MG255 was every bit as mediocre as you’d expect from a middle of the road camcorder. In strong lighting, the camcorder did just fine. Motion artifacting was apparent, but not overwhelming. JVC has had plenty of time to tweak the MPEG2 codec, and we probably won’t see any more improvements from here on out. All the development has moved on to HD video formats.
The biggest problem with the GZ-MG255 is the haloing that occurs between contrasty areas. See the image above (blown up 200%), shot in adequate indoor lighting. The blue color surrounding the white tag is the result of a lens aberration, an imager issue, or a combination of both. Either way, it stinks, and you should expect better from a camcorder this expensive. This, combined with the inadequate auto white balance, makes the GZ-MG255 a meager performer.
Video Resolution (4.65)
We used a DSC Labs video resolution CamAlign chart under even bright light settings to test the resolution of the JVC GZ-MG255. Resolution is measured in line widths per picture height (lw/ph). At best, the MG255 displayed a horizontal resolution of approximately 310 lw/ph and a vertical resolution of 300 lw/ph. The results, surprisingly, were higher than the GZ-MG555, which has a larger imager with more pixels. We’re not entirely sure why this discrepancy occurred. What we do know is that this test does not measure the raw resolution of the chip itself. Rather, we’re gauging the resolution of the final, outputted image – what the consumer will actually see on their screen. This video has undergone processing and compression, which can severely curtail sharpness.
In some of the denser areas of the CamAlign chart, the MG255 produced a moiré, a wavy pattern that appears when lots of detail surpasses the resolution of a camcorder’s imager. While this effect is not uncommon among similar camcorders (in fact, almost all camcorders will moiré if pushed far enough), the MG255 threw in some discoloration along with moiré, making it all the more ungainly. This did not occur with the GZ-MG555.
Low Light Performance (4.97)
When the lights drop down to 60 lux (equivalent to a softly lit room) the color retention is reasonably good. The GZ-MG555 has a larger CCD, but did not produce nearly such vibrancy to the color. However, the overall exposure levels were about the same (grays, blacks, and whites measured equal). It appears JVC may have done some tweaking to color processing between these two models. The GZ-MG555 may be meant to process colors more like a pro camcorder, which is much less saturated. This holds true for the GZ-MG70 (Review, Specs, $499.95) and GZ-MG77 (respectively, the 2005 and 2006 antecedents of the GZ-MG255), which have similar, though not identical, imagers. Both managed the same general exposure levels but with less saturated colors. A lot of people will prefer the GZ-MG255’s strong colors. True, they have a rather neon tinge, but they pop. The only way to correct them is to lower the exposure. There is no onboard color correction feature.
Like all JVCs, the GZ-MG255 gives you the option of turning off the automatic gain control (AGC). At best, this gives you the ability to reduce the noise. More often, it shows you the limits of the imager and lens system, which produce a much darker picture when access to gain is denied.
The camcorder also offers shutter speed control, which can prove useful in low light. Apparently, it was not necessary at 60 lux. When we dropped the shutter down to 1/30 of a second, the image appeared virtually identical to the Auto mode.
At 15 lux with the AGC on, the noise starts to pick up considerably, particularly as bluish patches. Remarkably, the camcorder is still able to capture a decent amount of fine detail, at least when shooting still objects. Moving objects will likely appear much fuzzier. The camcorder also had trouble focusing at this light level, so set up your shot and give the camcorder a moment to adjust before you hit record.
When the shutter speed was dropped to 1/30 with AGC on, exposure levels went up, but the blue noise remained, becoming even more noticeable.
At 15 lux with the AGC off, the image went more or less black and the camcorder had great difficulty focusing.
Additional low light testing involves two parts. First, we shoot a GretagMacBeth color checker chart at 60 lux to determine color accuracy, noise, and saturation levels. Second, in order to determine sensitivity, we monitor IRE levels and slowly drop the light down until the camcorder is able to produce peak IRE levels of 50. At best, the camcorder produced 50 IRE at a light level of 14 lux, slightly better than the GZ-MG555. However, the GZ-MG255’s saturation boost cost it valuable points in color error, which measured 11.6 (the GZ-MG555 scored a more accurate 8.7). The GZ-MG255’s saturation level was 122.6 percent, and the noise level was 0.6775 percent.
Overall, we were pleasantly surprised with the low light performance. The GZ-MG255 proved itself to be an improvement over last year’s GZ-MG77, and it compared moderately well to the step-up mode, the GZ-MG55, offering brighter, though less accurate, colors.
Stabilization (5.19)
In order to test the GZ-MG255’s stabilization capabilities, we used our custom-built camcorder shake emulator, made exclusively for Camcorderinfo.com. The camcorder was tested at two speeds. Speed one is the equivalent to the handheld embrace of a camcorder while filming during a casual walk. Speed two is a bit more tumultuous, simulating a light jog or bumpy car ride with camcorder in hand.
At speed one, the GZ-MG255’s DIS performed admirably with an 87.5 percent shake reduction. Unfortunately, it was a different story when it came to speed two. The GZ-MG255’s DIS was only able to lop off 14.29 percent of net shake—the catalyst for the GZ-MG255’s mediocre stabilization score. Overall, the GZ-MG255 scored better than the GZ-MG555. This may be due to differing internal stabilization mechanisms or internal weight distribution.
Wide Angle (9.6)
We tested the GZ-MG255’s field of view by setting the camcorder to Manual mode with digital image stabilization off, pulling the zoom back to a full wide angle, and mounting it to a tripod. We then measured the left and right angles using a vertical laser. Both measurements were then subtracted from one another to derive the wide angle. The GZ-MG255 displayed a maximum field of view of 47 degrees in 16:9 mode and 42 degrees in 4:3, which is fairly average for a consumer camcorder. These measurements are identical to last year’s GZ-MG77 wide angle test.