You have needs. People make lenses to suit those needs. That makes choosing one lens from hundreds kind of overwhelming. I'll take you through the steps for choosing your first...or second lens.
If you’re just starting out the answer is simple.
Use the kit lens.
It will be able to handle 90% of the pictures you want to take. It’ll go wide enough for landscapes and tight enough for great portraits. Upgrade only when you hit a limit with the lens.
If you have outgrown the kit lens and are looking to upgrade, it all comes down to what you shoot.
When shooting landscapes you generally want a wider lens. Something with the wide end between 10mm-24mm. You don’t need a large aperture since you’ll usually be shooting from f8 and up. Feel free to save money by buying a lens with a smaller aperture.
The portrait photographers bread and butter lies somewhere between 50mm and 100mm. People look really good when shot at these focal lengths. To get that out of focus background that makes your subject pop, you’ll want to spring for the lens with the widest aperture you can afford. Anything wider than F4 will be perfect.
When shooting street photography you want something wide enough to show the scene but not to wide as to distort people or objects. Anything around 35mm will do you just fine.
If you can’t get close to your subject, like with sports or wildlife photography, you’ll need a telephoto zoom like a 70-200mm. Using these longer lenses can be challenging so you might want to look for one with image stabilization. Even the smallest movement on the camera side shifts the field of view greatly with a telephoto.
The key is to figure out your budget and needs, that will guide you to the perfect lens.
Tips: If you want versatility buy a zoom like a 24-105mm. It’s better to spend money investing in lenses rather than new cameras. You can use old lens with a new camera in the same brand. So buy the best lens you can afford.