Chances are you bought your first DSLR with a kit lens (something like a18mm-55mm, or 24mm-105mm, for example). Kit lens are versatile and will serve you well as you get used to your new camera. But at some point you’ll start thinking about what lens you should buy next.
Many people will lust after a new zoom or telephoto lens, but I always suggest picking up a simple 50mm prime lens.
Most popular brands offer solid, high-performing 50mm prime lens (f1.8) at reasonable prices (between US$100-200). For a second lens, I recommend getting a low-cost f1.8 50mm lens – you’ll be amazed, and pleased, with their performance. Higher-end, 50mm lenses (f1.4 and f1.2) are available, but they’re bigger, heavier, and expensive.
Prime or fixed focal length lenses offer great value as they are usually inherently sharper than zoom lenses. This is partly due to there being less moving parts inside the lens, and less lens elements.
Prime lenses also produce beautiful ‘bokeh’ (how the lens renders the out-of-focus areas behind your subject) than most zooms.

50mm lenses are also lightweight (between 4-6 ounces, depending on the brand), and small, which make them easy to carry and unobtrusive when you’re using them.
The 50mm prime lens is also versatile. It’s great for street photography and wide open landscapes. It’s also a great portrait lens, just long enough to remove distortion from your subject’s face and flatter them a bit.

In addition, the 50mm f1.8 allows low light photography that kit zoom lenses can’t (even if they cover the 50mm focal length), because of their aperture limitations. A 50mm f1.8 lens will give you 2 F-stops more to open up versus a typical kit lens. You’ll be amazed at the photos you’ll be able to take in low light situations where flash can’t be used. Best of all, you’ll be able to take the shots without having to increase ISO to ridiculous levels.

So, what’s the disadvantage to purchasing a 50mm prime lens? Simple… you’re going to have to learn how to use your feet! Instead of just zooming-in as you do with your kit lens, you’ll have to take a couple of steps closer to your subject. But, believe it or not, what seems like a disadvantage at first will actually make you a better photographer. You’ll be forced to actually think about composition more, and in doing so your photography will improve.
The shots you’ll be able to take with your new 50mm lens will renew your enthusiasm for taking photos.