In recent years the price of dSLR (Digital Single Lens Reflex) cameras have been falling and more and more people are taking interest in these cameras, which during the early days of digital photography remained solely in the reach of professional photographers. In this article I will go over some of the pros and cons of stepping into the world of dSLR photography be it your first camera or an upgrade. I'd like to leave most the technical details of the differences between the two types for another day and focus more on which is best for you. For this article I will use P&S (Point and Shoot) to refer to any non-SLR camera.

What are the differences?

The Viewfinder

An SLR camera uses a mirror in front of the film (in this case, a sensor) to bounce light into a 5-sided prism at the roof of the camera into the viewfinder. The major benefit of this is you see exactly what your camera sees without having to watch a small display like a TV. Everything happens as smoothly as anything else you can see with your naked eye. On the other hand, P&S cameras don't have a mirror and prism system to bounce the night around into the viewfinder and must rely on either an LCD or a separate (usually poor) viewfinder to show you what's going on while taking a photo. This is one of the largest benefits of an SLR camera.

Lens Choices

The second major benefit is that almost all SLR cameras have interchangeable lenses, which allow you to choose a particular lens for any interest you happen to have. Every major manufacturer of SLR systems has lenses available for all sorts of photography from wide angles for architecture to macro lenses for taking photos of insects.

A P&S camera will almost always have a more compact lens than an SLR due to the smaller sensor used. Smaller image sensors mean the lens doesn't have to produce a sharp image on a relatively large are and therefore is more compact. This is one of their greatest strengths as the equivalent lens on an SLR can be thousands of dollars and several pounds in weight.

Image Quality

Due to the larger image sensor size in a dSLR they're virtually unmatched in all aspects of image quality. They're also capable of much lower noise at higher sensitivity levels (ISO speed).

As of this writing there is one camera with a large sensor; the Sony R1 which has a sensor the size of common dSLR sensors.


Camera Speed

Focusing, processing and writing speeds are all generally faster on a dSLR. Many P&S cameras can hold their own in frames per second, as they don't have a relatively large mirror to move around.

Camera Size

An SLR style camera is generally larger than a P&S camera due to the need for a mirror and viewfinder prism while not even taking a lens into account. Adding a large lens to this makes the size difference that much larger. You will not find any dSLR that can be stuck into a pocket whereas most digital camera manufacturers make P&S that are extremely small and be stashed in almost any pocket.

Photo Storage

Almost all dSLRs use Compact Flash as a storage format. Although CF cards are larger than other formats, they have the most storage space and are generally quite robust and therefore can stand slightly more abuse than smaller, more flimsy cards. Most other cameras use one of the newer formats such as Secure Digital or Memory Stick.

Nikon's lower end dSLRs (the d40, d40x, d50) use Secure Digital cards. Canon exclusively uses Compact Flash in its current lineup.

Camera Accessories

With a dSLR if you can name it you can probably get it for your camera. Everything including lenses, viewfinder eyepieces, battery grips, flashes to cases exist for almost every dSLR out there. With P&S cameras many models offer conversion lenses (small lenses that attach to your existing lens), cases and small flash units. Find out what accessories are available for the camera you're interested in as limited options can leave you facing the possibility of buying a new camera to add a feature other cameras might have available.

Conclusion

Now that you have a basic understanding of the differences that are most relevant between the two, you now have a choice to make that's really based on what you plan to do with your camera.

My personal view is to get a dSLR unless you absolutely need a very small camera or are only a casual user who wants to take family photos. The initial cost is about the same for either a digital SLR. By taking the SLR route you can invest in better lenses later when you feel you can make use of them or have specific interests (such as bird photography). In addition to that you will have higher performance, higher image quality and more accessories available to you.

I use a P&S camera (Canon PowerShot S2 IS) for day-to-day camera use when size is a restricting factor. For everything else I use my wife's dSLR (Canon Digital Rebel).