Tuesday, December 23, 2008
D-SLRs For The Professional
2008 was a big year for D-SLRs, and there are now more choices than ever for pros seeking a primary or backup camera. Check out some of the key innovations and the latest models.
When we last left the D-SLR Wars a year ago, high-resolution LCD monitors and Live View shooting were the hot items. These are still terrific features, and more cameras offer them, but the new hot thing is HD video in a D-SLR. Nikon announced its D90 with 1280 x 720p HD capability at Photokina 2008, followed shortly by Canon’s introduction of the EOS 5D Mark II, with 1920 x 1080p HD video capability.
HD Video. Professional still photographers had never had Live View or video capability and were more concerned with features like image quality, operating speed and AF performance. But HD video capability adds a whole new dimension to a photographer’s repertoire: the ability to provide clients with high-quality motion and sound, along with high-quality still images.
While they currently lack a full-fledged HD camcorder’s manual controls during shooting, the D-SLRs offer some big advantages over camcorders. The D-SLRs’ much larger sensors theoretically provide better image quality, especially at higher ISOs and in dim light, while the resulting reduced depth of field produces a professional cinematic “look” that a camcorder can’t deliver. D-SLRs accept a wide range of lenses, including fisheye, superwide, supertelephoto, macro and even tilt-shift, many with built-in image stabilization. And with the D-SLR, you can record a high-resolution still image at any time during video recording simply by pressing the shutter button (there will be a brief gap in the video each time you do this, of course).
LCD Monitors. Sony’s DSLR-A700 introduced the 3.0-inch, 920,000-pixel LCD monitor to the D-SLR, soon followed by Nikon’s D3 and D300. Now Canon has joined the fray with the EOS 50D and EOS 5D Mark II, Nikon has added the D3X, D700 and D90 and Sony the DSLR-A900 with these clear high-res devices that feature four times the resolution of most D-SLR LCD monitors.
Resolution. Of course, the megapixel battle continues, although we hope it’s about to run its course. The more pixels you put on a given-sized sensor, the smaller they have to be. And the smaller the pixels, the higher the noise and lower the dynamic range, all other things being equal. There are neat technological tricks the manufacturers use to make smaller pixels see light more effectively (gapless microlenses being one of the latest), but ultimately a given-sized pixel can hold only so many photons. It looks like the new EOS 50D’s 15.1 megapixels on an APS-C-sized sensor and the Sony DSLR-A900’s 24.6 megapixels (and the new Nikon D3X with 24.5 megapixels) on a full-frame sensor are about the limit, at least with current technology.
High-megapixel images also take up more room on memory cards (a 4 GB card will hold around 100 of the Sony A900’s 24.6-megapixel images) and require more computer horsepower (those 24.6-megapixel A900 images open to around 69 MB in Photoshop).
Format. Another big trend is full-frame sensors. Last year, we had three full-frame models: Canon’s EOS-1Ds Mark III and EOS 5D, and Nikon’s D3. Today, that number has more than doubled, with Canon’s aforementioned EOS 5D Mark II, Nikon’s D700 and D3X, and Sony’s DSLR-A900 joining last year’s entries. (The EOS 5D Mark II will replace the 5D when current stock runs out.) Full-frame benefits include larger pixels for a given megapixel count, larger and brighter viewfinders, and lenses that frame just as they do on a 35mm SLR. Full-frame disadvantages include cost and no “telephoto” factor for sports and wildlife photographers.
Bit Depth. More cameras are going to 14-bit A/D conversion. JPEG images are 8-bit, with 256 gradations from white to black. RAW 12-bit images have 4096 gradations, and 14-bit images have 16,384. This produces much smoother gradations and more natural colors, and gives you much more “headroom” for using Levels and Curves corrections in Photoshop.
Image Processors. New image processors deliver quick operation with big image files, better image quality and higher ISOs. While the ISO 25,600 figures settable with some cameras might be more hype than useful, image quality at all ISO settings is much better than it was even a year or two ago, and ISO 1600, 3200 and even 6400 are quite usable with some cameras. Improved noise-reduction systems improve image quality at all speeds.
Anti-Dust Measures. Olympus introduced the Supersonic Wave Filter in its first D-SLR, the E-1, back in 2003. This clever device uses supersonic vibrations to effectively remove dust from the image sensor. Today, most D-SLRs offer a similar feature. There also are dust-repelling coatings on the low-pass filter covering the sensor, and even features that map dust and automatically remove it with software in your computer.
Image Stabilization. Canon introduced the first SLR lens with a built-in image stabilizer back in 1995, and Minolta gave us the first D-SLR with sensor-shift stabilization in 2003. Now, Canon, Nikon, Leica/Panasonic, Sigma and Tamron offer stabilizer lenses, and Olympus, Pentax, Samsung and Sony offer D-SLRs with sensor-shift stabilization. In-lens stabilization stabilizes the viewfinder image as well as the recorded one and can be optimized for each lens design; but you need the stabilized lenses to get it. Sensor-shift stabilization works with all lenses, but stabilizes only the recorded image, not what you see in the finder. Both systems are effective and a boon to those shooting handheld.
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