Today’s D-SLRs and advanced compacts pack plenty of processing power into their little bodies, and their manufacturers are taking advantage of it to provide better image quality, quicker operation, longer battery life and a number of features that wouldn’t have been possible not so long ago—things like Live View with face-detection AF, HD video, automatic lighting correction, automatic lens correction, exceptionally good high-ISO performance and more.
It all starts with a powerful processor. Canon’s DIGIC 4, Nikon’s most recent EXPEED, Olympus’ TruePic III+ and V, Panasonic’s Venus Engine HD, Pentax’s PRIME II and Sony’s latest Bionz processors provide the power to support the evolving capabilities of the newer digital cameras.
Each camera model, be it a D-SLR or compact, features processing custom-tailored to that camera and its target users’ needs. The processor works with the image sensor (which also is being improved with each new generation) and the latest algorithms to provide some impressive new capabilities, including HD video and more.
While compact digital cameras have provided Live View operation from the beginning, this handy feature made its D-SLR debut just three years ago in the Olympus E-330. Today, Live View is available in more D-SLRs than not, from entry-level through high-end pro models.
The traditional SLR optical (TTL) finder works well for most serious shooting, but there are benefits to Live View. One is that using the LCD monitor to frame images makes composing at odd angles easier (although, sadly, only a handful of D-SLRs with Live View have tilting/swiveling monitors that make odd-angle compositions easy).
Another Live View advantage is easier manual focusing in dim light situations (or when using a teleconverter, which reduces light transmission and makes for a dim viewfinder image). The Live View image is bright and can be magnified greatly for easier focusing. This is best done with the camera mounted on a tripod, and bear in mind that there’s no built-in dioptric correction for the LCD monitor as there is for the SLR optical viewfinder. If you need glasses to see up close, you’ll need them to use Live View. Live View also provides 100% coverage of the actual image area, important for precise framing and compositions.
Some D-SLRs (mostly higher-end models) provide both phase-detection and contrast-based autofocusing in Live View. Phase-detection is the AF system employed for non-Live View shooting (Canon calls this Quick mode, Nikon calls it Handheld mode, Olympus calls it AF Sensor mode) and offers the advantage of quick performance. The drawback is that the SLR mirror must drop down into viewing position for autofocusing to occur, which momentarily disrupts the Live View. Contrast-based AF (Canon calls this Live mode, Nikon calls it Tripod mode, Olympus calls it Imager AF mode) provides focal-plane focusing right off the image sensor, so there’s no blackout of the Live View during focusing. The drawback is that contrast-based AF is slower than phase-detection AF. Sony’s DSLR-A300, A330, A350 and A380 models have a second sensor that provides the Live View image, so the camera’s quick phase-detection AF can be used with no disruption of the live image. For more about the differences between phase- and contrast-detection AF, see the article “How Autofocus Works” on our website, dpmag.com.
With some Live View cameras, you can send the live image to a computer via a USB connection (or wirelessly with an optional wireless remote unit) for viewing on a computer monitor and operate the camera from the computer via the supplied or optional software. Seeing the live image and previewing exposure and effects on the big computer monitor is wonderful and not just limited to studio work—you can send the Live View image to a laptop computer in the field.
An outgrowth of Live View, video is another feature long found in compact digital cameras, but only recently introduced to the D-SLR. Full 1920×1080 HD video amounts to more than two megapixels per frame, 27 times that of the 320×240 video found in most compact cameras and nearly 7 times that of 640×480 SD video. To handle that much information at 24 or 30 frames per second requires lots of processing power. Today, we finally have that power in the latest processors.
Nikon’s D90 was the first D-SLR to offer video capability, followed shortly by Canon’s EOS 5D Mark II. Several cameras now feature some form of HD video capture:
• The D90 and Nikon’s new D5000 produce 1280×720 HD video (plus 640×424 and 320×216 standard video) at a “cinematic” 24 fps, with mono sound via a built-in microphone when desired.
• Canon’s “semi-pro” EOS 5D Mark II shoots 1920×1080 full HD video or 640×480 standard video at 30 fps, with mono sound via a built-in microphone or stereo sound via an optional plug-in mic.
• Canon’s new entry-level EOS Rebel T1i shoots 1920×1080 full HD video
at 20 fps, along with 1280×720 and 640×480 video at 30 fps.
• Panasonic’s SLR-like Lumix DMC-GH1 can record 1920×1080 full HD video at 24 fps and 1280×720 video at 60 fps.
• Pentax’s new K-7 can shoot 1280×720 HD video, as well as 1536×1024 and 640×416 3:2 video, all at 30 fps.
A number of new compact digital cameras also offer HD video, but D-SLRs provide several advantages. Since the image sensors in D-SLRs are much larger than those in compact digital cameras (and typical HD camcorders), you can obtain a cinema-like narrow depth of field not possible with the smaller sensors. Because the pixels on the larger D-SLR sensors are much larger, high ISO/low-light performance is much better. You also can use a wide range of interchangeable lenses to shoot movies with a D-SLR, while compact cameras and consumer HD camcorders come with built-in zoom lenses that limit your options.
Many newer digital cameras can identify human faces in a scene and adjust focus, exposure, white balance and even flash to render them optimally. The exact implementation varies from camera model to camera model (i.e., how many faces can be tracked, how you can override the camera’s selection and how it employs focus, exposure and white-balance adjustments), but the feature is handy for people shots.
Now, face detection itself is gaining new features. Some cameras not only can detect faces in a scene, they can tell when those faces are smiling, alerting the photographer and even firing the shutter automatically when the smile occurs. Some smile-detection systems take multiple shots, so you can choose the best smile. A Blink feature warns you when a subject’s eyes are closed, so you can retake the shot.
Some face-detection systems can differentiate between children and adults, allowing you to give priority to one or the other. Some can even recognize a specific person—you can register a favorite subject’s face and name, an
d the camera will recognize that person when he or she appears in a shot, adjusting focus and exposure accordingly. Some even go the next step, allowing you to retrieve images based on who is in them. While current face-detection systems can detect only human faces, systems that can detect animal faces are in the works.
Automatic Lighting Correction
Some scenes contain too great a brightness range for a normal exposure to record detail throughout. Automatic lighting correction helps address this. Auto lighting correction comes under various names: Auto Lighting Optimizer and Highlight Tone Priority (Canon), Active D-Lighting (Nikon), Shadow Adjustment Technology (Olympus), Dynamic Range Expansion (Pentax) and Dynamic Range Optimizer (Sony), for example.
Basically, these systems adjust exposure and in-camera processing to retain more detail in bright and dark areas. Sony (and presumably newer Nikon) D-SLRs work on the RAW data from the sensor before it becomes an image and don’t suffer the problems of working on compressed image data. This requires lots of processing power and can slow the shooting rate or limit the number of shots that can be made in a continuous burst, but provides very effective results.
With some systems, you can choose among several strength settings or let the camera make the adjustments automatically. You also can switch automatic lighting correction off when it’s not needed or when shooting speed is a priority.
The new Pentax K-7 has an HDR feature that captures three images, then combines them in-camera to bring out detail in all areas of the image.
AF SLRs have long been able to track moving subjects (some more effectively than others) through their continuous AF mode. In order to compensate for the small distance a subject moves during the brief span between the moment you fully depress the shutter button to make the exposure and the moment the exposure is actually made, most AF SLRs feature predictive AF, in which the AF system calculates the subject’s predicted position at the instant of exposure (based on successive focus readings and the assumption the subject will continue to move in the direction and at the speed it was moving when those readings were taken).
Minolta came up with Multi-Dimensional Predictive AF many years ago, which could even handle subjects that changed speed or direction—pretty amazing. Sony now incorporates that in its D-SLRs (having acquired Minolta’s D-SLR technology when Minolta left the camera market). Other manufacturers are a bit tight-lipped about the inner workings of their AF systems, but today’s predictive autofocusing works very accurately, regardless of brand.
Nikon’s new D5000 can “memorize” brightness and color information from a selected area of the subject and track the subject as it moves across the frame, even if it momentarily leaves the frame. When the subject reenters the frame, the camera will pick it up and, assuming you have the shutter button depressed halfway, focus on it. Note that autofocusing doesn’t occur while the camera is tracking the subject with this feature.
Styles basically provide the digital photographer with the ability to “change films” to get a different look ideally suited to a specific photo situation. Canon calls these Picture Styles, Nikon calls them Picture Controls, Olympus calls them Picture Modes, Pentax calls them Custom Images, and Sony calls them Creative Styles. Basically, these provide a number of presets, such as Standard, Portrait, Landscape, Neutral, Monochrome (black-and-white) and more. You can then, if desired, fine-tune the sharpness, saturation, contrast and color tone. For monochrome images, you can apply colored-filter effects and tone the images sepia, blue and other hues. You can even create your own styles, save them and recall them when desired.
Compacts and D-SLRs Share Processors?
You may notice that some compact digital cameras seem to use the same image processors as their manufacturers’ D-SLRs. For example, some of Canon’s newer PowerShot compact models feature the company’s latest DIGIC 4 processor, as do the EOS 50D, EOS 5D Mark II and EOS Rebel T1i D-SLRs. Canon tells us that in its case, it’s indeed the same processor hardware, but the programming is unique to each camera model.
In the case of other brands, the processor itself may vary from camera model to camera model. Nikon’s recent digital cameras employ the company’s EXPEED processing system, tailored to the needs of each specific camera model. Likewise, Sony’s Bionz system used on its D-SLRs and most Cyber-shot compacts is optimized to each camera model’s specific features and needs. Pentax’s PRIME processing is found only in its D-SLRs. In any event, you can rest assured that each new D-SLR and compact digital camera has a processor and processing system optimized for its specific needs and users.
Built-in Special Effects
A number of entry-level and midrange D-SLRs offer built-in special effects. For example, Nikon’s new D5000 lets you apply fisheye, color outline, color intensifiers, cross-screen (starburst) and soft effects to already-shot images in-camera. Olympus’ E-30 lets you apply six Art Filters as you shoot, checking them on the Live View monitor. The company’s new E-P1 lets you apply the Art Filters in still and HD video mode. Both also let you display a previously shot image on the Live View LCD monitor and use it as a guide to position a second image over it—handy for placing a telephoto moon in a nighttime landscape image, for example.
Software that makes it easy to stitch several digital images into a wide panorama has been around for quite some time. But now there are cameras that have this ability built-in. For example, with the Sweep Panorama mode in Sony’s DSC-HX1 compact, you press the shutter button and move the camera horizontally or vertically. The camera will shoot continuously at high speed and then seamlessly stitch the images together. This is another part of a trend of incorporating features into cameras that previously could be done only after the fact via software.
Some pro SLRs have always been able to shoot rapid sequences, great for sports-action. Now, even some point-and-shoots offer such capability. In fact, some can outdo the best SLRs. For example, Casio’s Exilim EX-F1 can shoot 6-megapixel still images at up to 60 fps and video at up to 1200 fps, with a top shutter speed of 1?40,000 sec.!
Live View Multiexposure
Multiple-exposure capability—the ability to make several exposures on a single f
rame of film or in a single digital image—has been around for years. But even this old favorite has seen a new wrinkle of late. For example, the Olympus E-30 and E-620 let you display an already-shot image on the LCD monitor in Live View mode and then use it as a guide for superimposing a second image. This makes it easy to position both images precisely.
Sigma’s D-SLRs and digital compact cameras like the new DP2 don’t have a lot of the bells and whistles—they’re straightforward cameras with easy-to-use (and easy-to-figure-out) controls. What they do have is the unique Foveon full-color-capture CMOS image sensor and a TRUE (Three-layer Responsive Ultimate Engine) processor designed to get the most from it.
Conventional CCD and CMOS sensors don’t see colors; they just see brightnesses. In order to provide color information, a grid of colored filters is positioned over the sensor, so that each pixel is covered by a red, green or blue filter. How do the pixels get color information for the other two primary colors? From the neighboring pixels, via complex interpolation using proprietary algorithms.
The Foveon sensor used in Sigma digital cameras takes advantage of the fact that different light wavelengths penetrate silicon to different depths, in effect “stacking” three pixel layers—a top one that records blue light, a middle one that records green and a bottom one that records red. Thus, every pixel site actually does record all three primary colors of light, no interpolation (and no image-softening anti-aliasing filter) required. The result is sharp images with accurate colors and no “artifacts.”
Automatic Lens Correction
Two major problems inherent in camera lenses are vignetting and chromatic aberrations. Vignetting means the center of the image is brighter than the edges and especially the corners, due to the light falloff. Some recent D-SLRs are programmed to compensate for this light falloff automatically when a lens in the camera’s onboard database is being used.
Among other things, chromatic aberrations cause the infamous “purple fringing” around subject edges in high-contrast images. A number of recent D-SLRs automatically compensate for this when you use a lens that’s included in the camera’s onboard lens database. These cameras come with a number of popular lenses in the database, and you can add others via supplied software.
Some cameras—Nikon’s new D5000 and Pentax’s new K-7, for example—can even correct for barrel and pincushion distortion as you shoot with wide-angle and long lenses.
Yet to Come
This is just a sampling of features you can use today; there are lots more to come. Many of the technologies and components necessary to advance digital imaging are just starting to appear.