What Are SLR Cameras, and Are They Worth the Money?

If you're an amateur photographer who has ever gone camera shopping, you know that camera come in a range of prices from dirt cheap to hideously expensive. You may also have noticed that any camera marked "SLR" includes a large jump in price. Why? What does "SLR" mean? And is it worth the extra money? This article will explain what SLR cameras are, how they work, and if it's worth the step cost for your type of photography.

The Two-Angle Problem

Have you even taken a photograph, only to develop it and discover that the picture is slightly off-center from the image you framed through the viewfinder? This happens because when you frame a picture, you're not actually able to look through the camera lens. The shutter and film are in the way. Instead, you look through the viewfinder, up and off to the side of the actual lens. This results in two slightly different angles of view between the picture you frame in the viewfinder, and the picture the camera lens actually takes. This problem is especially noticeable with close-up shots.

How SLR Technology Fixes This Problem

SLR (Single-Lens Reflexive) is the technology that, through the clever use of prisms and mirrors, fixes this problem by allowing you to actually see through the actual camera lens to frame your photograph.

SLR cameras lower a tiny mirror into the lens box. This mirror reflects the image coming in through the lens up into a prism, which then flips the image around (to cancel out backwards mirror-image effect) and then bounces it through the viewfinder. This allows both the camera and the photographer to see the exact same image being framed, except for the brief second when the photograph is actually being taken. This is the "Single-Lens" that SLR refers to.

Digital Camera and Shutter Lag

The arrival of digital "point-and-shoot" cameras initially seemed to make SLR cameras technology obsolete. Digital cameras, after all, have "live preview" which does allow the photographer to see exactly what the camera lens is seeing on an LCD screen on the back of the camera. It quickly became apparent, however, that digital cameras had their own set of problems-specifically, shutter lag.

"Shutter lag" is the delay between when you press the shutter button and when the digital camera actually takes the picture, due to the camera having to calculate the exposure and focus settings. With some digital cameras, the shutter lag can be an excruciating two to five seconds. Although that may not sound like much, those few seconds are all it takes for the camera to be bumped, the subjects being photographed to move, the camera angle to change, or focus to be lost-all of which can spoil a shot and are unacceptable to professional photographers.

Digital SLR Cameras

Digital SLR cameras (DSLR) combine the best of both technologies. The SLR mirror & prism system allow the photographer to see through the lens, including focus, lighting, and exposure. When the shutter button is pressed, the mirror in the shutter box is flipped up out of the way, exposing the image sensor for a split second to capture the image.

Consequently, DLSR cameras are much, much faster than digital point-and-shoot cameras. For example, even the highest-end digital point-and-shoot camera still has a shutter lag time of at least half a second. In contrast, the Minolta/Sony a500 (only a midrange DSLR camera) can take five photographs per second. DSLR cameras combine the convenience of digital cameras with the accuracy and speed of SLR film cameras.

Do You Need an SLR or DSLR Camera?

The answer really depends on the type of photography you are doing. If you are doing landscape or still photography, the benefits of SLR cameras are negligible. If you are doing close-up photography, you'll definitely find SLR cameras useful. Finally, if you are doing action photography-such as sports, wildlife, or reporting-the shutter lag of a digital camera is unacceptable, and the sheer speed of a DSLR camera alone makes it worth the higher cost.