- Aspherical
This lens mounts to any Canon EOS camera and works on both "full frame" cameras like the 5D as well as the "APS-C" style digital SLR cameras, but the aperture is neither communicated to nor controlled by the camera body. As such, you can use the lens in "M" manual exposure mode or "A" aperture-priority mode, and in both cases you will physically move the aperture ring to the aperture of your choice and it will stay at that aperture even before the exposure. Users of EOS cameras with HD video mode may prefer that the aperture isn't communicated, because this allows videos to be taken at the larger apertures (not possible in bright light with EOS autofocus lenses).
With a 35mm equivalent focal length of ~127mm and that f/1.4 aperture, this Bower 85mm lens opens up photographic opportunities you'll never get with your zoom. Capture close portraits of singers on dark stages with only spotlights on their faces, and those background lights will be soft cascades of low-contrast coloring. With the big f/1.4 opening, you'll have enough light to stop subject motion. Or try it in brighter conditions at fast shutter speeds and low ISOs to make great shots of people in front of blooming trees, with background flowers almost looking like paintings. It isn't easy nailing manual focus at f/1.4-2.0 (nor for that matter is it easy for an AF system), but you'll get better with practice, and soon be making many snaps that stand out in a crowd.
This lens was truly created with large-aperture shooting in mind. Though a fine performer with plenty of contrast and resolution at f/5.6-f/11 apertures, it is at its best shooting between f/1.4-2.8, where it presents a high-peak-resolution focus point surrounded by lower resolution/contrast out-of-focus areas. Rather than just sharpness all around, for many pictures it is this stark drop off in resolution and contrast that effectively draws a viewer's eye towards a subject.