DSLR Buying Guide - Basics

Digital SLR camerasFrequently called DSLR cameras. are quite different from fixed-lens digital camerasOften incorrectly called Point&Shoot digital cameras, of which only some are.. The main advantages of a digital SLR camera are: less image noise at high-sensitivities, interchangeable lenses, a reflex viewfinder and much faster speed of operation. Note that only the reflex viewfinder is truly a property unique to DSLRs. 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 lenses as well as some not-too-old manual focus film SLR lenses can be used on a DSLR but usually show a different angle-of-view.

Note that there currently exists several interchangeable lens cameras which do not a have reflex viewfinder. Instead, they use their rear LCD for framing, an EVF or an accessory optical tunnel viewfinder which must be matched to a specific lens' field of view. These produce some high quality images, very similar to entry-level DSLRs, in a smaller package but without the speed of operation that most DSLRs achieve. These cameras are known as SLD or ILC.

• Digital SLR cameras are defined by their reflex viewfinder and DSLRs are the most efficient when using it. Recent DSLRs feature live-view which enables the rear LCD to show an approximation of the scene. Currently, live-view either means slow autofocus or a cropped preview and is rarely WYSIWYG.
• 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 camera 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 otherNote that even if a lens attaches, all its features may not be supported..
• SLR lenses are zoomed and manually focused by handIn auto-focus mode, an SLR uses a motor to focus. This is faster, more precise and much more responsive than typical electronic zoomsOnly a few fixed-lens cameras have a mechanical zoom..
• 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.
• DSLRs started recording video at the end of 2008. Capabilities are improving but only a handful can focus continuously while filming.
• Battery life on a DSLR is significantly longer than most fixed-lens digital cameras unless live-view is used, since the LCD consumes a lot of power and the sensor needs to be constantly active.