There are many differing versions of the Canon 50mm lens. Which one you select will be determined by what you are using the lens for and the {effect-visual effect you are trying to achieve. Each has a different aperture range, size and weight. The aperture of the lens is known by its f number.
The f/1.8 lens not only takes very clear and sharp photos but provides professional quality at an affordable price. Because of its plastic construction, it's light weight and compact. With excellent control of depth of field, you can really make your subject pop. With as light as this lens is, the plastic lens mount should be more than adequate to hold the lens in place. For longer or larger lenses, a more traditional metal mount might be preferable. There is no manual focus on this lens but if you are looking for an affordable lens that combines ease of use with quality photographs, then the f/1.8 lens is a perfect fit.
The f/1.4, like the f/1.8, takes superior pictures with crispness and clarity. Like the previous lens, it allows control over depth of field to bring the subject to the forefront of the picture. The middle of the road for the Canon 50mm lens line, the f/1.4 produces a more evenly distributed blur effect for those objects in the background of a picture. Though this may not seem important, unnatural blur in the background can often distort the overall likability of a picture, making it seem almost rendered on a computer graphics program. A little higher priced, the f/1.4 is a step up from the f/1.8 overall. Unlike it's less costly counterpart, this lens has a metal camera mount and an ultrasonic motor. This is the perfect lens when you are ready to move up from the f/1.8.
Much higher in price, the f/1.2 L boasts a quieter motor and higher color saturation. Additionally, it creates photos with higher contrast than its less costly counterparts. This lens is geared more towards the serious hobbyist than the casual user. With faster auto-focus and a sturdier build, this lens is excellent for taking pictures from portraits to city skylines and takes superior pictures in lower light.
Unlike the lower end lens, it allows manual focus. If you're looking for the ultimate all around lens, then the f/1.2 is the lens for you. Although a lot more expensive, the quality of the photos reflects the cost.
When deciding on which Canon 50mm lens you want to buy, you need to consider your budget and the type of photos you will be taking to insure you get the best value for your money.