| Canon EF 300mm f/2.8L IS USM | ||||
| f/ | Center (l/mm) |
Corner (l/mm) |
||
| 2.8 | Excellent | 59 | Excellent | 45 |
| 4.0 | Excellent | 74 | Excellent | 53 |
| 5.6 | Excellent | 74 | Excellent | 50 |
| 8 | Excellent | 59 | Excellent | 47 |
| 11 | Excellent | 47 | Excellent | 43 |
| 16 | V. Good | 42 | Good | 35 |
| 22 | Good | 37 | Good | 36 |
| 32 | Acceptable | 33 | Acceptable | 31 |
|
Hands on: Beautifully finished in Canon's familiar white surface and well-balanced, but at its lab-measured 5.6 pounds, this lens is definitely designed to be used on a tripod, where the lens' numerous controls are easily accessed and operated. That said, for its class, the lens is acutually lightweight, thanks to its magnesium construction. The lens' numerous features include Canon's quiet USM motor, exclusive Image Stabilization control, and a focus pre-set control. The latter stores a specific focusing distance in the lens' on-board memory. After presetting the distance, you turn the ¼-inch focus-recall ring that's conveniently positioned next to the manual focus ring to automatically bring the lens to the programmed focusing distance. The Focus-Recall feature works even in manual-focus mode. The lens' dual-mode Image Stabilisation operates with both static and moving objects. With IS engaged we noted slight vibration in the lens and camera; however, we saw no evidence that this vibration adversely affected image sharpness. Among the lens' new or unusual features: four "AF off" buttons spaced evenly around the lens barrel. You use the buttons to temporarily lock focus when an object moves between the camera and subject. Also unusual is an extended infinity focus setting that adjusts the infinity point to take into account focus shifts that can occur at extreme temperatures. Th elens also has an unusual rubber ring located on the lens mount for above-average dust and moisture resistance, a set of neckstrap grommets, and a drop-in filter drawer for Canon's 52-series filters that has an unusual spring-loaded clamping mechanism to hold the drawer in place. Additional features include a 3-way focus delimiter (full range; 8.2 to 21 feet; and 21 feet to infinity), and a removable tripod collar. The lens' manual focusing ring is 1 5/16 inches wide and clad in an easily grippable rubber-like material. As with select other Canon USM lenses, the manual focus ring lets you fine-tune focus, even in auto-focus mode. MF action is just slightly over-damped in our estimation. Barrel markings include a rather small focusing scale with Imperial (green) and metric (white) numerials, plus a single-aperture depth-of-field scale for f/32. |
In the lab: Due to the very large front diameter of this lens, we were not able to conduct our usual SQF and field curvature tests, but results of our line/mm resolution tests indicate overall excellent performance, especially at maximum aperture (see chart). At minimum aperture, resolution dips in to acceptable range, probably due to diffraction, which is normal. Terrific performance for a lens of this speed. We noted slight pincushion distortion. Exposure accuracy at film plane was extremely accurate except at maximum aperture, where we found about ½-stop underexposure due to light fall-off. In the field: Test slides were very sharp and contrasty from centre to corners at all apertures. Flare was very well controlled at all apertures. Light fall-off was gone by f/4, an excellent showing. Autofocus was very fast, smooth, and quiet. Conclusions: Overall, a very impressive optic and probably the sharpest 300mm f/2.8 we've tested. Certainly the most featured. With the special 1.4 and 2x teleconverters that are matched to Canon's USM line of IS super teles, plus the Image Stabilisation feature and the lens' image quality enhancing elements of ultra-low dispersion glass, this 300mm willl beckon strongly to every serious Canon-shooting nature and sports photographer, despite its hefty price. |