A digital SLR (DSLR) camera is a digital camera, but not all digital cameras are DSLR cameras. There are a number of important things that differentiate between a DSLR and a normal digital camera, and knowing these differences can help you choose the right camera for your photography needs.
Differences Between Digital and Digital SLR Cameras
A "digital camera" can be a DSLR, an SLT, a mirrorless camera, a bridge camera or a point-and-shoot. For the purposes of this comparison, the term "DSLR" will reference a digital single lens reflex camera, while the term "digital camera" will reference consumer-grade digital cameras used to take simple point and shoot pictures.
By far, the most substantial difference between a standard DSLR and a standard digital camera is the amount of control the user has over the camera itself. For advanced users, a DSLR camera offers the freedom to manipulate camera settings in a way that gives them complete creative control over their images. For less advanced users, a point-and-shoot digital camera is far easier to use but you have very little control over the settings.
Most consumer level digital cameras will not give you access to options like aperture control or independent image settings. They also won't allow you to adjust exposure compensation while using the built-in flash and they make it very difficult to adjust ISO settings.
On the other hand, a DSLR is designed to provide the photographer with the option of having complete control over all camera functions. Using these functions effectively, however, requires a certain amount of research and training. DSLR cameras also usually have "auto" modes which take over these functions if you prefer.
Ease of Use
A DSLR can be as easy to use as a consumer point and shoot camera if you set the DSLR to full auto mode. In full auto, you are allowing the camera to take control of focusing, ISO settings, aperture diameter and all other necessary functions. In this sense the DSLR works much like a standard digital camera. The digital camera is much easier to use simply because it has far fewer options and functions to learn.
The issue is that while a DSLR can function in this way, it is absolutely not the best investment to make if you plan on just shooting in full auto. DSLR cameras are often significantly more expensive than point and shoot cameras. If you wish to learn how to actually utilize all the features of your DSLR to get maximum return on your investment, then it will require a lot of research and work on your side.
Since most consumer-level point and shoot cameras are not equipped with an apparatus allowing for manual focus, they are reliant upon auto focus. The auto focus on most consumer cameras is very sluggish, and this creates a lag time between when the shutter button is pressed and when the actual photo is captured.
By contrast, a DSLR camera with a lens set to manual focus will take the photo the instant you press the shutter button. This lower lag-time means you lose fewer shots to the time delay caused by a sluggish auto focus.
A DSLR allows you to attach different lenses to the front of the camera, whereas a point and shoot camera does not. With a point and shoot camera, you are limited by the lens that is built into the camera itself. This severely limits your ability to get wider shots, high-quality macro shots, and extreme depth of field for portraits. If the lens is not of high quality, you may also experience intense chromatic aberrations in your images under bright light.
With a DSLR, you can swap out lenses for different creative needs. If you want a shallow depth of field for a portrait, you can use a 50mm f/1.4 lens. If you want a wide, expansive landscape shot, you can trade out the 50mm lens for a 16mm wide angle lens and set the aperture to f/8 for a wide depth of field and excellent sharpness. The control this provides you as a photographer is immeasurable.
DSLRs have significantly larger sensors than consumer digital cameras. This can have a huge impact on your depth of field, field of view, and overall image quality.
Many people mistakenly believe that the amount of megapixels on a camera's sensor is what dictates the image quality. This is unfortunately not the case, and you can actually end up getting lower quality images with a high-megapixel sensor if the sensor is not large enough to realistically accommodate those photosites. This is why images taken from high-megapixel cameras with small sensors are usually very susceptible to high image noise. Having a camera with 5 or 6 megapixels will provide you with more than enough image quality for any size print.
Larger sensor cameras generally have larger pixels that produce lower image noise even at higher ISO settings, giving the DSLR an advantage in photo quality over the point and shoot digital camera.
DSLR cameras are usually much more expensive than a simple point and shoot camera. The cost of the camera itself is only the beginning, as lenses for DSLRs can cost anywhere between a few hundred dollars to a few thousand.
Which One Should You Get?
In the end, a DSLR is probably not the best investment for someone who has no intention of learning how to use manual controls on their camera. DSLRs are bulky, they are complex and there very expensive. This is especially true when you factor in the cost of lenses. If you want to learn more about photography and have an ambition to learn the mechanics of taking a great photo, then a DSLR may be a great investment.
As new technologies make their way to market, the raw image quality gap between DSLRs and consumer point and shoot cameras is ever-smaller. With this in mind, the most important thing to consider when you're buying one of these cameras is what you'll enjoy shooting with the most. Don't get a DSLR just because you think that's what "photographers" need, and don't limit yourself to a point and shoot because you think DSLRs are too hard. Get what you think will give you the best bang for your buck.