Well, first go read this post, and if you just bought your camera, I will try to talk you out of buying anything.
So, why do you want a lens? Other than that glass is cool. Are you wanting more reach, to get images of birds in the trees? Are you wanting to take pictures of kids in low light? Would an external flash be better? Would you like something with a zoom, or something with a fixed focal length? Do you have $300, or $3000? Do you know what f/3.5-5.6 means?
You need to be able to answer those questions to make a truly informed decision. Reading the Digital Photography Book (post) by Scott Kelby would help with this too.
Ok, lets take a look at some reasonable (for photography) options.
If you are looking for some “fast glass”, the traditional recomendation is the “nifty fifty.” Fast glass, or a fast lens, is a lens that has a very large minimum aperture size. This refers to a small aperture number, such as f/2.8, or f/1.4. The kit lenses are usually of a variable aperture, meaning they are not constant through out the zoom range. Zoom lenses are usually more expensive to make in a constant aperture, so most people look to get a fast lens with a single focal length. What does this do for us? By “opening up” the lens to a wide aperture, you let in more light, so the shutter speed can be faster when taking available light pictures. Also, your depth of field gets smaller, meaning that the area in the photo that is in-focus is smaller. This can be good and bad depending on the picture¬† you are taking.¬†
The Nikon 50mm f/1.8 that most people call the “nifty fifty” has been a staple of most photographers, and the price hovered around $120 – $150 depending on where you get it. (amazon) There are a couple of issues with this lens though. First of all, your camera may not work with it. Cameras like the D40, and D3000 do not have a traditional motor drive in the camera body. This means that autofocus will not work with the nifty fifty. I used this 50mm lens manually focusing on a D40 for quite some time. Worked great for flowers, not for kids. You need a AF-S lens in Nikon terms to get auto focus. That means that the lens its self has a motor in it. But, it makes the lens more expensive. Amazon has this version for about $440.¬†
Problem #2. The 50mm lens is a great lens. It used to be called the “standard lens” and many film era cameras shipped with just this lens (a 50mm). So what’s the problem? Sensor size. If you want to use your new “fast glass” to take pictures indoors without flash, the 50mm¬†can be too long a focal length. You might want to consider the Nikon 35mm f/1.8 AF-S instead. (amazon) ¬†On most digital cameras, the sensor is smaller than a film negative. This makes lenses appear to have a longer focal length, and why the 35mm works better indoors. 35mm x 1.5 = 52.5mm on a APS-C “crop sensor”. (I am not going to get into this anymore today, but there are lots of places to read about this,¬†like¬†here)¬†The good news is that the 35mm lens is cheaper. Amazon has it for about $200.
How about if you want to make small, or far away subjects look bigger in the viewfinder? A longer zoom? Or move your feet. Seriously. Many shots can be taken by simply getting closer to your subject. Also, telephoto lenses are not just for “making things bigger”. They also compress the scene. They make the background and the foreground appear closer together. For birds and¬†other critters, you may not be able to get close enough with your feet. If you want a telephoto, you are looking at getting something that zooms to 200 or 300 in a variable aperture, or you are spending really big money.
Some of¬† you may already have this lens, the Nikon 55-200mm f/4-5.6 AF-S¬†VR. (amazon) Sometimes this lens is bundled in a two lens kit with some cameras. This lens is only $200 – $250, and for a lens of this price, is really quite good. The VR (vibration reduction) helps to reduce hand shakyness, especially at slower shutter speeds. This was my first lens purchase, and one that I found useful.
What about macro? Fixed focal length zooms? Wide angle? All in one zooms? Take it slow. Learn your camera and the lens you have. See how close¬† you can get with your lens. You can get fairly close “macro-ish” shots with a kit lens. Move your feet and get closer to subjects. The 18mm of most kit lenses is reasonably wide. Learn how to use that. That said, I will tackle some of these options in another post soon.
If you want a little bit more reach, a sharper image, and have some extra money, the Nikon 70-300mm f/4.5-5.6G AF-S VR is considered a very¬†good lens for the money. You can find this item for less than $500. (amazon) ¬†At $500 the cost is getting more expensive, but is still reasonable in the world of camera lenses. I don’t own this lens, but many people I respect have and like this lens.