|
Canon EF 17-40mm f/4 USM L (full format) - Review / Test Report |
|
Lens Reviews -
Canon EOS (Full Format)
|
|
Page 1 of 3
Review by Klaus Schroiff, published April 2009
Special thanks to Philipp Schürmann for providing this lens!
Introduction
The Canon EF 17-40mm f/4 USM L is one of the most popular L class lenses thanks to its relatively affordable price and its dual purpose scope - it can serve as a standard zoom lens on APS-C DSLRs and it's an ultra-wide zoom lens with an attractive range on full format DSLRs.
The build quality of this lens is exceptionally high just as you would expect it from a Canon L lens. No wobbling whatsoever and smooth controls - almost perfect. The lens is also designed to survive in harsh conditions with a sealing against dust and moisture. The outer length of the lens remains constant although the inner lens tube moves a little according to the zoom setting. Needless to say - the front element does not rotate during focusing or zooming operations.
The lens has a ring-type USM drive based on a front-focusing system resulting in an extremely fast AF speed. AF accuracy was also not an issue during the field tests. Typical for ring-type USM lenses full-time manual focusing is always possible in one-shot AF mode.
| Specifications |
|---|
| Optical construction | 12 elements in 9 groups inc. 3x aspherical and 1x SUD elements |
| Number of aperture blades | 7 (circular) |
| min. focus distance | 0.28 m (max. magnification ratio ~1:4 @ 40 mm) |
| Dimensions | 84 x 97 mm |
| Weight | 475 g |
| Filter size | 77 mm (non-rotating) |
| Hood | included, petal-shaped |
| Other features | gel filter slot (rear), sealing |
|
