Start with the Kit Lens
What's the kit lens? It's the one that came with your entry level digital SLR. 99% chance its a 18-55mm f/3.5-5.6 which is the standard these days. Why start there?
- It's cheap (between $100 - $200 on its own, probably less as part of an entry level DSLR kit).
- It's reasonably sharp. Since this is the lens most people will start with, it's also how they will judge their camera and the brand as a whole. Manufacturers know better than to start you off with a total piece of crap.
- It's good for general photography. This zoom range is going to cover 95% of your typical subjects. 18mm is wide enough to get decent landscapes and 55mm is tight enough to capture a headshot without being right in someone's face.
Fact is, the kit lens leaves a lot to be desired in terms of maximum aperture. In low light situations, you're either married to your pop-up flash (yikes!) or you're forced to jack your ISO through the roof and cope with the horrendous noise.
So what's the solution? Get a fast prime, something with a maximum aperture like f/1.4, f/1.8 or f/2. Besides giving you low-light performance, large apertures produce a very shallow depth of field which is great for emphasizing your subject and turning the background into a pleasing blur.
Fast primes come in a variety of focal lengths, but I'd recommend staying around 35mm or 50mm which tend to be the most useful for general photography. So how do you choose, 35 or 50? Try taping down the zoom ring on your kit lens at 35mm for a while, then 50mm. Which one do you find more natural? There's your answer.
The good news is they can be relatively cheap (about $200). If you're worried about not being able to zoom, relax, you've still got your kit lens. Also, you'll be surprised how often you choose to keep your fast prime on your camera and leave the kit lens in your bag.
Save Some Money, Evaluate Your Limitations
Your next lens purchase might cost you a couple dollars, so save up some money. While you're doing that, evaluate your limitations. Which of the following problems do you run into the most?
- I can't zoom in far enough on distant subjects. This probably means you're shooting sports or wildlife a lot. The solution? Buy a telephoto lens. There are a number of inexpensive telephoto zooms out there, mostly in the 55-200mm or 70-300mm zoom range. Don't expect a large maximum aperture, f/4 - f/5.6 is typical. It's possible to get fast telephoto zooms (f/2.8 and under) but the price tag is always four digits, so you might wanna hold off on those.
- I can't zoom in far enough / focus on very small subjects. Then you need to buy a macro lens. The key spec to look for is magnification ratio: you want "1:1". This is the realm of true close-up photography. They tend to come in 50mm, 100mm and 200mm varieties (roughly). The longer the focal length, the further away you can be and still get 1:1 magnification. The longer focal lengths also cost more, so unless you are photographing poisonous snakes you'll probably be fine between 50 - 100mm. Get ready to pay though, a decent macro lens starts at $400.
- I can't zoom out far enough to get the whole scene. Uh oh, you need a super-wide angle lens. The general rule is, the wider the better. 10mm is better than 12mm is better than 14mm, etc. You can always crop in later, and the whole reason to buy a super-wide angle lens is to get a SUPER wide view! Keep an eye out for fisheye lenses when you're shopping, they are a different animal. If you don't mind a distorted perspective, fisheyes are fun, but they aren't going to give you straight lines like a traditional wide-angle lens.
- I keep having to change lenses. Maybe you need a super zoom. They can encompass a very large zoom range (such as 18-200mm) and give you the flexibility to capture a lot of different shots quickly without stopping to change gear. Be warned, you get what you pay for. The cheap super zooms are pretty junky, I suggest you spend a bit more to get real quality.
