In the video world, resolution specifications are packaged and labeled using nomenclature like “1080p” and “HD,” whereas in the realm of digital still cameras we tend to identify the various plateaus using raw numbers only. The danger inherent in using labels is that sooner or later the marketing guys run out of superlatives and the names get longer as technology progresses. We expect to see “Super Duper Extra High Definition” on the horizon soon, to be followed, no doubt, by SDEHD Mark II shortly thereafter.
In any case, video resolution has at least two tags: the vertical pixel count and alpha label. 1080p, for example, is also known as Full HD and has a vertical resolution of 1080 pixels. The “p” signifies “Progressive” scan and means that each image is captured as a full frame of video, the alternative to “i” or “Interlaced” video in which two consecutive fields are captured and reassembled into one full frame. Think of it as the difference between a pull-down window shade and horizontal window blinds. For photographers, the advantage of the Progressive scan system, clearly, is that each frame is complete and can be independently edited.
With a frame size of 1920×1080 pixels, this is the highest quality currently available. The Canon EOS 5D Mark II and Panasonic GH-1 are two examples of cameras that offer full-HD, 1080p video capture.
720p HD (High Definition)
The 1280×720 is more than adequate for most applications and delivers outstanding quality overall. The Nikon D90 and popular D5000 cameras are 720p.
HDV (High-Definition Video)
HDV is captured at 1440×1080 and displayed as Full HD (1920×1080).
SD (Standard Definition)
Popular because it is the de rigueur for Hollywood DVDs, SD offers 720×480 resolution that matches NTSC television rendering.
SVGA=800×600 and VGA 640×480
These labels are quite familiar to most still photographers who recognize that, although smaller, SVGA and VGA offer reasonably good quality (close to commercial DVD output) and are compact and easier to handle. You’ll find many compact digital cameras with these options.
Divide a VGA 640×480 frame into four equal portions and the result is a tiny quadrant that’s nearly worthless in terms of video resolution. QVGA, or Quarter VGA, has a niche as an e-mail attachment but really nowhere else.
Most digital still cameras use relatively inefficient Motion JPEG to squeeze video into manageable file sizes. Motion JPEG is capable of compression in the range of 20:1, a far cry from the more sophisticated MPEG-4/H.264 standard which can compress on the order of 50:1. In this sense the word “format” is not to be confused with “file format.” Most video clips are saved as Apple QuickTime (.MOV) or Audio Video Interleave (.AVI) files. MPEG-4 produces smaller files, a significant benefit.
Prepare for the worst. HD video files can fill up a memory card faster than you can say “Who’s going to edit this?” A Pentax K-x, for example, shooting at 720p, can fit barely three minutes of HD video into 1GB of memory card space. If you shoot 1080p with a Canon EOS 5D Mark II you can expect about the same: Canon claims that 12 minutes of full HD will fit on a 4GB card. In any case, expect HD video shooting times to be short and files to be large.
The first is your video-enabled cellular telephone. The second is a DSLR or point-and-shoot digital camera. The third is the dedicated camcorder. Each category is further segmented, of course, as is the wont of the camera industry, and you can bet your house that further segmentation will occur as fast as markets begin to develop.
At first blush, a cell phone may seem like the worst choice for any serious video work. Think again. The current Apple iPhone, for example, can capture movies at VGA (640×480) resolution and at 30 frames per second. We’ll concede that this barely reaches the threshold of acceptable quality. Nonetheless, the omnipresent iPhone has a noteworthy advantage: It’s significantly more likely to be overlooked by security when you go to a rock concert, whereas your three-chip camcorder
won’t make it beyond coat check. And since video sharing websites (like YouTube) are the final destination for many spontaneous videos, VGA resolution is adequate.
Of equal importance, the cell phone market is huge. Enhanced video performance motivates buyers to upgrade. Put two and two together and you have a strong incentive for phone manufacturers to continue to improve video capture capability along the same lines that it has matured in digital still cameras. In fact, much of the heaviest lifting has already been done.
At the other end of the spectrum is the dedicated camcorder. On the lowest rung of the ladder you’ll find pocket-sized “shoot-and-share” camcorders that record on
SD memory cards (some on internal memory also, or on both). As an aside, be sure to use a SD card that’s at least a Class 4, otherwise it won’t be able to transfer data fast enough for satisfactory results. These little cameras are great as secondary recording devices, as an afterthought and for parties and backpacking. They’re sometimes overwhelmed by contrasty light, ill equipped for dim light and the audio quality suffers. But some deliver resolution as high as 720p and can snap stills, to boot. Any businessman who wants to add a little life
to boring PowerPoint presentations will do well to embed small video clips—and these tiny camcorders are one of the most convenient ways to create them.
Traditional camcorders are larger than their shoot-and-share cousins and offer distinct advantages. They often have articulated LCD screens for more convenient capture and playback, perform much better in low light and accept external microphones for improved audio. Because they use a larger sensor, image quality is
innately better. They’re typically equipped with extended zoom lenses, electronic viewfinders that are easy to use even in total darkness and can record on a variety of different media, depending on model. They also have superior autofocus systems that can keep moving subjects sharp even while panning. Plus, there are dozens and dozens of models available, from many highly reliable manufacturers, so it’s easy to find the right combination of features at the price that’s right for you.
Prosumer camcorders use “a three-chip” system (three separate CCD or CMOS sensors, one for each primary color) to deliver outstanding picture quality, accurate color reproduction and a wide dynamic range with virtually no color noise. They feature extremely high-quality optics, image stabilization and extended zoom lenses (20X optical zoom is typical). Many offer a variety of scene transition effects for on-the-fly enhancements, plus alphanumeric character recording (names, dates, locations) on top of the live video capture when required. As you’d expect, audio quality excels and all offer extensive external microphone options.
Of greatest importance to photographers is the addition of HD video capture to conventional digital still cameras. Nikon pioneered this frontier when they introduced the Nikon D90 with 720p HD capability in August of 2008, and made it ultra affordable with the Nikon D5000 in the spring of ’09. Other Nikon digital SLRs that