Canon EF 16-35mm f/2.8L

Utilizing Ring USM, the 16-35 L focuses fast, quietly and accurately. The focus and zoom rings are nicely sized, turn smoothly and are nicely damped. This lens does not extend with a small exception - the objective end lens elements move in/out slightly inside the lens barrel during focusing. All movement takes place behind the filter threads. If you have a filter installed, you will not have any external movement. Since the filter attaches to the lens barrel - which does not move, the filter also does not rotate. This matters when using a Circular Polarazing Filter or split neutral density filter. The common 77mm filter threads make sharing filters with Canon's complementing lenses easy.

At 16mm, the Canon EF 16-35mm f/2.8L USM Lens is sharp in the center even wide open (f/2.8) and improves little when stopped down. The 16mm full-frame corners are soft wide open (with a flat target - because of field curvature) and improve noticeably at f/5.6. At 16mm with a close subject distance, strong barrel distortion is noticeable even on a FOVCF body. Barrel distortion enlarges the center portion of the frame and shrinks the corners. This effect makes the center performance at 16mm seem especially good when in direct comparisons with lenses exhibiting less barrel distortion. You will likely notice this when comparing the 16-35 L's 16mm ISO 12233 resolution chart sample crops with other lenses and focal lengths. Distortion is much less of an issue with longer subject distances - I seldom find it to be a big issue in my real-life images.