Digital SLR performance and features
As with standard digicams, digital SLR features and performance vary widely. These are some of the most important differentiators.
|Performance and feature criteria|
|Resolution||Low end: 6 megapixels|
High end: 21 megapixels
|Frame rate||Low end: about 1.5fps to 4fps|
High end: 10fps
|Burst depth||Low end: 4 to unlimited shots|
High end: 7 to unlimited shots
|AF speed and tracking||Hard to quantify, but there are wide gaps in the AF performance of current digital SLRs, especially when tracking moving subjects. The top-end sports and news pro cameras definitely outperform the rest.|
|Ruggedness||Also hard to quantify, but another area where a wide gap exists between low-end offerings and the midrange-to-top sports and news pro cameras, which are sealed against moisture and made with more durable materials.|
|Viewfinder coverage and effective magnification||Low end: 95 percent or less; below 0.58x|
High end: 100 percent; 0.58x or higher
The effective magnification of a viewfinder is the optical magnification corrected for the focal length multiplier. For example, a dSLR with a stated/optical magnification of 0.94x and a 1.5x focal-length multiplier (APS-C sensor) would be 0.94 * 1.5 = 0.63. That's why Four Thirds-based cameras have stated magnifications over 1.0--they have to compensate for the 2x multiplier of the small sensor. Higher effective magnification and coverage is always better.
|Start-up, playback, mode-switching times||Low end: 1- to 6-second delays|
High end: Virtually instantaneous
|Viewfinder information||Varies widely. The more information you can see without taking your eye away from the viewfinder, the faster you can shoot.|
|Quality of auto white-balance system||None is perfect, but a good one saves lots of time and headaches for JPEG shooters. Those who shoot raw files have the option of correcting white balance with software after shooting.|
|Ergonomics||Impossible to quantify--and partly a matter of personal preference--but critical to efficient shooting. Our advice: try before you buy.|
|Image stabilization||Lens or body? With respect to the final photo produced, both work equally well. Optical stabilization has the advantage of letting you see the stabilized version while you're looking through the viewfinder, which can be crucial when framing at long focal lengths (beyond 300mm), but putting the technology in the lens generally results in more expensive lenses. On the other hand, mechanical (sensor-shift) stabilization will work with any lens you buy, making it a less-expensive long-run solution.|
|Video capture||Low end: 24 or 30fps 1,280x720 video encoded with Motion JPEG as an AVI file. |
High end: 30fps or better 1,920x1,080 video encoded with H.264 in MPEG-4 or Quicktime MOV format. Manual shutter speed and aperture controls.