Digital SLR Basics: Top 10 Facts, Advantages, Disadvantages

Digital SLR Basics

Digital SLR cameras are quite different from fixed-lens digital cameras. The main advantages of a digital SLR camera are: less image noise, interchangeable lens, a reflex viewfinder and faster speed of operation. Note that only the reflex viewfinder is truly a property unique to DSLR cameras. For an in-depth look at the differences between these two types of cameras read our article The Digital SLR Difference.

Today's digital SLR cameras all have interchangeable lenses. While this provides great flexibility, choosing the right lens or set of lenses can be more difficult than choosing the right DSLR. Most autofocus and some manual focus film SLR lenses can be used on a DSLR but usually show a different angle-of-view.

Top 10 DSLR Things To Know

	Digital SLR cameras are defined by their reflex viewfinder. DSLRs are the most efficient when using such a viewfinder. Some DSLR cameras also feature live-view which uses the rear LCD to show an approximation of the scene. At this time, live-view either means slow autofocus or a cropped preview, plus it is also not WYSIWYG nor does it allow access to all functions.
	A DSLR viewfinder sees through the lens. It is easy to judge focus - but not exposure - through it. You can't see how bright or dark a picture will come out before taking it.
	Optical zoom depends on the attached lens. It makes no sense to specify optical zoom when describing a digital SLR camera. Lenses which do not zoom are called prime lenses.
	A DSLR's focal-length multiplier is determined by the size of its image sensor. The angle-of-view of a lens mounted on a particular sensor is calculated using the focal-length-multiplier.
	The connector between an SLR camera and a lens is called a mount. Only SLR cameras and lenses with the same mount-type can be attached to each other.
	SLR lenses are zoomed and manually focused by hand. This is faster, more precise and much more responsive than typical electronic zooms.
	All DSLR cameras have full manual controls, manual focusing, custom white balance, high-ISO sensitivities, a hot-shoe for an external flash and can produce RAW images.
	Available apertures are limited by the attached lens. Available shutter speeds are determined by the camera.
	In fall 2008, Nikon with deliver the world's first DSLR with movie-mode. Until now, no DSLR had movie-recording capability. Soon after, Canon announced the first full-frame DSLR with movie mode.
	Battery life on a DSLR is significantly longer than most fixed-lens digital cameras unless live-view is used.

Advantages

Image quality produced by a DSLR is higher than most fixed-lens digital camera although it is strongly affected by the choice of lens. A combination of low image noise and high retention of details, particularly at higher ISO settings, places DSLR ahead of fixed-lens. DSLRs can also capture more dynamic range than the vast majority of fixed-lens cameras. However, both types of cameras are equally capable in terms of color, white-balance and exposure.

The most significant performance advantage of a DSLR is in terms of speed. Compared to fixed-lens cameras, a DSLR focuses faster and shoots faster for longer. Most other DSLR timings are noticeably faster too, including startup time and shot-to-shot delay.

Focusing speed is important when capturing a moving subject. The faster a camera can focus, the faster it will take a picture. Shot-to-shot times and burst speed are also faster at maximum resolution on every DSLR than any camera which is not the Casio Exilim EX-F1. Burst-mode is mostly used in action and fashion photography where capturing a precise moment is paramount. Not only do DSLRs shoot faster but they can take more shots in a single burst at a constant speed. This increases the chances of capturing a decisive moment.

Disadvantages

DSLR cameras, like everything else, have issues proper to them. The two main issues are price and sensor dust. Even the cheapest DSLR is priced above most fixed-lens digital cameras when one or more lens is included.

Sensor dust is simply dust that enters into a digital SLR while the lens is being changed. One way to minimize it is to buy a single versatile lens and leave it permanently on. Most recent DSLRs also incorporate a mechanism designed to shake-off sensor dust. This does reduce the problem but does not eliminate it.

Minor issues of DSLR cameras include the limited live-view functionality, shutter-sound and relative bulk. One cannot always preview how a picture will be exposed; Instead, metering and experience must be relied upon. DSLR cameras have a much louder shutter sound than fixed-lens digital cameras, this can be disruptive in quiet environments or when discretion is required. Finally, one cannot underestimate the impact of camera size. As a general rule, the larger the camera, the less pictures one takes.