Those who are just entering the field of DSLR photography can easily be intimidated by the sheer vastness of the information and choices out there. Therefore, I'll describe what I think of as a good starter DSLR kit, i.e. my kit. But before I do that, I'll present you with the bare minimum terminology that you need to understand if you're going to engage in DSLR photography. There are two foundational concepts you need to get your arms around -- focal length and aperture. In looking at these two major topics you will also get introduced to some other peripheral terms, which I have underlined so that you don't miss them.
- Focal length. The focal length is the distance between the lens and the film. (In the case of digital cameras, the role of the film is played by the image sensor.) Focal length is measured in millimeters (or mm) and is directly proportional to zoom. That is, the larger the focal length, the larger the zoom. A lens with a small focal length (i.e. low zoom) is also referred to as a wide angle lens. A lens with a large focal length (i.e. high zoom) is also referred to as a telephoto lens. A full-frame DSLR is also known as a 35mm because its image sensor (film) is 35mm in size. For a 35mm camera, a 50mm lens can be thought of as a default or normal lens (i.e. human eye perspective). In crude terms, a lens is wide angle if its focal length is less than 50mm and telephoto if its focal length is greater than 50mm. An extremely wide angle lens is known as a fisheye lens.
- Aperture. The aperture is the size of the hole that opens to allow light into the camera. Of course, the aperture opens when you click the shutter, i.e. take a picture. The aperture is measured in F-stops (e.g. F/1.8 or F1.8). The aperture size is inversely proportional to the F-stop size, i.e. the smaller the F-stop size, the larger the aperture size. As you might imagine, smaller F-stops (i.e. larger apertures) allow more light into the camera. This makes them more suitable for low light photography. A larger aperture is usually combined with a higher shutter speed and a lower ISO or light sensitivity (and noise) setting. This is done to avoid blurry photographs. The fact that large aperture lenses tend to be combined with higher shutter speeds causes these lenses to be referred to as fast lenses. Larger apertures also result in a shallower depth of field (i.e. subjects that are in focus appear sharp, but everything else appears soft or blurry).
- Camera. My camera is a Canon 450D (also known as the Rebel XSi EOS). I paid around $600 for it. It's not a full-frame DSLR (those cost a lot more). The Canon 450D, along with many other modern DSLRs, has a 23mm image sensor (also known as APS-C). One more thing. I like the fact that my point-and-shoot camera (Canon PowerShot SX100 IS) uses regular AA batteries, which can easily be replaced when they run out. However, although the Canon 450D uses a rechargeable battery, I am truly impressed with its battery life, which must be something like 20 times better than what I get with the PowerShot.
- Wide angle lens. My default lens is the EF-S 18-55mm f/3.5-5.6 lens with image stabilization that is part of the Canon 450D kit (you can buy either the kit for $600 or the camera body by itself for a bit less). The range of focal length (18-55mm) essentially equates to a 3x zoom (55/18 = 3). I take most of my pictures with this lens. (The EF-S in the lens specification refers to the lens mount, i.e. the type of interface between the lens and the camera.)
- Fast lens. I separately also bought a Canon EF 50mm f/1.8 lens for about $70 (this isn't part of the 450D kit). The larger aperture (f/1.8) makes it suitable for low light photography. It has a fixed focal length of 50mm (i.e. you can't zoom in or out). A fixed focal length lens is also known as a prime lens. Prime lenses generally have a higher optical quality than equivalent lenses with variable focal length (i.e. zoom lenses).
- Telephoto lens. Finally, I also bought a Tamron AF 75-300mm f/4-5.6 lens for about $130 (again in addition to the 450D kit). The range of focal length (75mm-300mm) essentially equates to a 4x zoom (300/75 = 4). However, relative to my wide angle lens (i.e. 18mm at the lowest end) it acts almost as a 20x zoom (300/18 = 20; not quite, but close enough).
- Tripod. A tripod comes in handy whenever you wish to avoid blurring or take pictures using the built-in timer. Blurring can be caused by (a) the combination of low light and slow shutter speeds, or (b) high zoom, which magnifies the shaking, or (c) fast moving subjects.
- Camera Bag. You obviously don't want to lug all of the above around without a nice sturdy bag. Having everything in a bag also makes it easier to ensure that you're not caught without your favorite lens just when you really need it.
Update (May 1, 2013)
I wrote the original blog post on Feb 28, 2009. After about 3 years of fairly rough use (including not covering up either end of the lenses after use), the autofocus on my Tamron 300mm lens stopped working. Not sure if the Tamron lens issue made a contribution, but about a year later my camera aperture started malfunctioning and I had to dump the camera. Canon offers a repair service that is only worthwhile for top of the line cameras. Lesson learned: treat your DSLR equipment with a bit more care than you would invest into a tennis racket. So, I bought a replacement camera (a used "good as new" Canon Rebel T3 EOS 1100D). I bought the camera via Craigslist (tip: take your lenses and memory card with you to test out the camera before you shell out the cash). I also bought a Canon EF 75-300mm 1:4-5.6 III USM lens to replace the Tamron. So far, everything has been working well. The Canon 300mm lens is clearly superior to the Tamron I had earlier. Again, I was able to buy it used (good as new) via Craigslist at a price comparable to what I had paid for the Tamron. What I have noticed recently, though, is that my Canon 300mm won't support the Canon EF extenders (also known as teleconverters or multipliers) because it has a mount with 7 electronic contacts instead of the 10 needed to support the extender. So, if I want more zoom power (who doesn't?), my only option is to get another lens.