Why A Kit Lens Is Just A StarterIn general, lenses included as part of a kit have lower-end construction and optics. The cost savings need to come from somewhere, and that usually means plastic mounts and less expensive coatings on the optics. You’ll also find that many kit lenses don’t have the more durable construction typical of a similar higher-end lens. But it’s an excellent way for you to get up to speed with your camera, and for casual use, it may be the only lens you need at first.
What You Can Expect From A Kit LensLet’s look at the popular Canon and Nikon kit lenses. Canon includes an EF-S 18-55mm ƒ/3.5-5.6 IS (Image Stabilizer) with its EOS Rebel series of cameras. By itself, this lens sells for about $160. Purchased as part of a kit with the body, the price drops to less than $100. On the Nikon side, the AF-S DX 18-55mm ƒ/3.5-5.6 VR (Vibration Reduction) zoom sells for about $185 on its own, but only adds $120 to the price of a D5000.
Both lenses cover the same range, with a 35mm-equivalent focal range of about 27-82mm, and feature the same variable aperture settings of ƒ/3.5 at the wide end and ƒ/5.6 at 55mm. Both lenses include the manufacturers’ versions of image stabilization, and both are optimized for the smaller sensor sizes of the typical digital SLR.
Balancing Cost And PerformanceThe whole reason behind the kit approach is to get you into a camera that you can use immediately and at a set price. The lenses included with many kits are entry level in an effort to keep the costs to a minimum. They’ll usually cover the “normal” range of shooting, from moderate wide to moderate tele, in part because these lenses are easier and less expensive to manufacture and in part to encourage you to buy additional lenses when you want to go wider or longer.
While pro-quality lenses are often made from metal components, the average kit lens will have a plastic body, making them a little less durable, but much lighter in weight. Top-of-the-line lenses, like the L series from Canon, also include expensive coatings and glass elements, along with more robust focusing systems.
Finally, you’ll notice that high-end lenses tend to be larger than the typical kit lens. This is because they’re faster—often with a constant maximum aperture of ƒ/2.8 or even faster, rather than the variable ƒ/3.5-5.6—which requires larger optical elements. This lets you shoot in lower light and gives you more control over the depth of field in your images, but it comes at a price of size, weight and cost. As an example, the Nikon 18-55mm ƒ/3.5-5.6 kit lens with a $185 price jumps to $1,250 when you go to the faster 17-55mm ƒ/2.8 lens.