All the different types of lenses out there can be very confusing, so I'm here to give you a good solid basic working knowledge of what lenses are all about!
There are basically three main classifications of lenses, and you will know their classification by their focal lengths listed in mm (millimeters):wide - anywhere from 45mm and lower
medium - 50mm
telephoto - anywhere from 55mm and higher
A 50mm medium lens gives you a normal field of view just as you see it with your eye. Then on one end, a telephoto lens will make things appear closer than they really are (commonly thought of as "zoomed in"), and on the other end, a wide-angle lens will make things look farther away than they are (commonly thought of as "zoomed out").As you can see in the diagram, a wide-angle lens will give you the widest field of view. This "zoomed out" view is useful if you don't have a lot of room to back away from your subject, such as inside a house. A wide lens is also great to take with you on vacation if you want to take pictures of large buildings (cathedrals, castles, etc.)
A telephoto lens is useful when your subject is farther away, such as photographing a child in sports or dance performances.
A wide-angle angle lens will make the background look like it's farther away from your subject, whereas a telephoto lens will make the background look like it's much closer.
A wide-angle lens also adds some degree of distortion. The wider the angle, the more distorted the image will be. Objects that are close to the camera will look much larger than objects that are far away. And elements near the edges of the photo will have a stretched-out look. This distortion can be used to enhance the artistic quality of your images...
Or it can just look really weird...
Just be careful about getting people's limbs or especially their heads near the edge of the frame!Some lenses have a zoom capability so they will have a range of numbers, for example an 18-55mm lens will cover a wide - medium range, while a 55-250mm will cover a medium - telephoto range. Other lenses are fixed so they don't zoom. With a fixed lens you have to move closer or father from your subject with your feet! This may seem inconvenient at first, but you soon get used to it and the fixed length lenses tend to deliver slightly sharper images than zoom lenses.
Lenses are also labeled with another number, which refers to the aperture (or how wide the lens can open). This is useful to know because the wider your aperture, the more background blur you can achieve. So if you like that blur, get a lens with the lowest possible aperture number (like 1.2 or 1.8). The fixed length lenses typically have wider aperture capabilities.So, what lenses should you buy? Keep in mind that Canon cameras require Canon lenses and Nikon cameras require Nikon lenses! There are also a couple of other good quality lens brands that can be used on both Canon and Nikon and they are usually less expensive.
I highly suggest starting with the Canon or Nikon 50mm 1.8 - This is a fixed length medium lens (neither wide nor telephoto), so you'll need to get used to "zooming with your feet". It has very wide aperture capabilities which is important to get that beautiful background blur! I would use this lens to take pictures of people as well as inanimate objects (mostly small details but maybe even landscapes).Then I would look for a zoom lens in the wide range (the Tamron 17-50mm 2.8 looks good) and a zoom lens in the telephoto range (the Sigma 70-200mm 2.8 is a nice choice). Look for something with a low aperture number. Be aware that if the lens gives an aperture range, it means that the lower aperture doesn't work if you zoom beyond a certain point, so I would avoid lenses like that.
Before purchasing a lens, I highly recommend reading reviews on it. Fred Miranda is my favorite site for reviews. Also, many camera stores rent out lenses very affordably, so that's an additional way to make sure that a lens is good before you buy.As you embark on your lens hunt, feel free to email me (firstname.lastname@example.org) with any questions you may have! Also, if there is anyone who has a larger photography budget and would like some information on higher-end cameras and lenses, please email me. I would love to help you out!