Canon L lenses are top quality pieces throughout the line. They typically have wide apertures (fixed throughout the zoom range for most L zoom lenses). Canon L lenses share a rugged build quality. The build quality combined with wide minimum apertures usually result in Canon L lenses being heavy.
The image quality of the Canon L lenses is generally as good as it gets. Contrast, sharpness, color, bokeh (background/foreground blur quality), flare, CA (Chromatic Aberration) … All are excellent. Full Frame camera body owners will especially find L series lenses to be (on average) significantly sharper toward the edges of the frame compared to lesser lenses.
 
Available Focal Lengths:
100mm, 85mm, 50mm, 35mm, 24mm, 14mm