A 50mm lens is a must have in any photographer’s bag! For the most part, 50mm lenses are extremely inexpensive. A Canon 50mm F1.8 II lens (which is the one I currently use) runs for about $100. If you’re going for higher-end lenses, expect to dish out a couple hundred dollars or more depending on the brand and availability but a 50mm is still cheaper than most of the other lenses your will find out there. In general, all you really need is one that is around F1.8 as that aperture is wide enough for most uses.
The 50mm lens mimics the field of view of the human eye and this will translate into your photos. Note that on a crop-sensor DSLR, the 50mm produces an angle of view closer to 75-80mm. As a result, the 50mm lens can also be a great focal length for portaits/candids. A 50mm can also be used to shoot in low-light, for portraits at a wedding (or portraits in general), photojournalism, macros, candids, etc. Even if it isn’t your primary lens, your 50mm should be your backup as it can do almost anything you may demand of it. Not to mention, the 50mm lens is so light and compact that you’ll be able to shoot anywhere without the intimidation factor of a giant lens. With all this in mind, remember that you are the photographer and you need to make your tools work for you.
Now my personal review on the Canon 50mm F/1.8 II- The pictures it produces are great! The lens it’s self does feel a little plasticy and toy-like but it’s a big bang for your buck and sturdy enough. ! I didn’t see a big enough difference in the picture quality of the Canon 50mmF/1.8 II and the Canon 50mm F/1.4 to justify the extra $200. The build on the 1.4 is the main difference between the two but I actually prefer the bokeh of the 1.8. The Canon 50mm F/1.2 is an amazing piece of glass if you have the money but if you are an enthusiest or hobbiest the 1.8 will suit you just fine.
Let me know what lens is your must have lens!
Here is one of the first pictures I took with my 50mm on my Canon 60D.