The 50mm lens are sometimes called standard lens because they closely match the magnification of human eye. Like most fixed aperture lenses, these 50mm primes have much brighter aperture (smaller F number) than zoom lenses.Having wider aperture allows these lenses to be more flexible in low light conditions. The wider aperture lenses let us take pictures with shallow depth of field (DOF) resulting in beautifully blurred backgrounds for portrait photography among others.
Canon 50mm Prime Lenses
Lenses with F number smaller than 2.0 are usually expensive but the 50mm models are the exception. Due to the ease of construction, the 50mm lens with wide apertures are very affordable – especially the F/1.8 and F/1.4 models.
Just to put things in perspective, most kit zoom lens at 55mm focal length have aperture of F/5.6. A lens with aperture F/1.4 can actually capture 16 times more light.
Canon has no fewer than three lenses with F/1.8, F/1.4, and F/1.2 apertures. On the highest end we have Canon EF 50mm F/1.2 L lens – the luxury model for professionals, and at the other end, we have very economical Canon EF 50mm F/1.8 lens. Currently the Canon EF 50mm F/1.8 II lens is the best value lens available for Canon SLR cameras. It should be noted that the F/1.8 model uses MM (Canon Micro Motor) while the F/1.4 and F/1.2 L models use Ring USM (Canon Ultrasonic Motor).
