The new 50mm f/1.8 isn't exactly groundbreaking, but it's looking like a more solid option that is still a bargain at $125. The first big difference between this model and the old one is the fact that the autofocus motor has STM technology, which is designed to give smoother autofocus during video. It also has a wider and better-placed focus ring, and more blades on the iris (7 vs. 5), which should make the out-of-focus areas smoother.

Canon has also managed to shrink the minimum focusing distance down to 14 inches. And to top it off, its physical size is just a tad smaller, which also means they've changed the front filter size to 49mm, though the lens mount is now metal to go along with this mostly plastic lens. Judging by the MTF comparison, image sharpness is about the same in most places as the previous lens, but that's more or less to be expected considering the price

Here's a look at the differences between the 50mm STM and the previous version (courtesy of B&H):


While it's often called the nifty fifty, once you get it on APS-C (or Super 35mm) sized sensors, it's a lot less exciting as the resulting image doesn't look nearly as wide as on a full-frame camera. The biggest change that was really necessary if you want to do any manual focusing is the placement and size of the focus ring, which now looks wider and isn't crammed at the front of the lens. It's still not going to be as nice as using a real cinema lens or an old manual focus prime, but it's certainly a step in the right direction. Either way, it's still a fantastically useful lens considering its small size, low weight (though this model is an ounce heavier), and inexpensive price. 

The 50mm will be shipping later this month, and is available for pre-order right now. 

Canon EF 50mm f/1.8 STM Lens