Canon 300mm F4L EF USM IS - Description:
The Canon 300mm IS lens is compact L-series telephoto with an Image Stabilizer which compensates for camera shake with the equivalent effect of a shutter speed two stops faster.

Two Image Stabilizer modes are provided in 300mm Lens:
Stabilizer Mode 1 (the same mode featured on the EF 75-300mm f/4-5.6 IS USM) and the new Stabilizer Mode 2 which steadies the image during horizontal or vertical panning. Mode 2 detects the panning direction automatically. The closest focusing distance for is 4.9 feet (1.5 m).

The Canon 300mm L is a prime lens from Canon is a popular choice among advanced amateur photographers as well as professionals. 300mm L lens is relatively compact dimensions and price tag.

As a ‘white’ L class lens offering is built to last. The metal bodied barrel of Canon 300mm lens is of the ‘drainpipe’ type, being almost constant in diameter throughout its length. The slightly narrower collar just in front of the mount in 300mm L lens allows finger room next to the camera’s grip and on the opposite side carries the two switches for AF/MF and focus limiter that allows 3m to infinity and the full scope of 1.5m to infinity. Next up in the 300mm L Canon's Lens is the tripod mount collar with a single position foot and a ribbed knob for fixing. Strangely, although the collar has a central mark, there are no markings on the lens to line them up with.

Next along the barrel of Canon 300mm L-Series lens on the left side, are the IS (Image Stabilisation) controls consisting of two slide switches. The lower, larger one is the on/off and the smaller, upper one controls the two modes. The first is for static shots and the second is for panned shots. Across the centre of the barrel in front of the manual focus ring is a standard distance window marked in metres and feet on the surface .

The manual focus ring in 300mm L Lens is a good 50mm+ in size with a nice, rubberised ribbed surface that is easy to grip. The model I had a slight forward and backward play in it, but this was not enough to be annoying. The autofocus of 300mm Lens is silent in operation although, for an L lens, it did seem a little sluggish even on a 1 series camera! The manual ring does not rotate during autofocus and is nicely torqued when over-riding or manual focussing.

Forward of the focus ring in Canon 300mm L lens is a sleeved, built in lens hood that slides back and forth and is locked with a quarter anti-clockwise turn. Once locked, it stayed in position well.

The weight , not excessive for the type, gives a feeling of being fairly bomb-proof and solidly built.

Optical Quality
Distortion is well controlled, with a pincushion effect of only 0.254% recorded with the Imatest module. Contrast and colour rendition are both up to Canon’s normal standards with a slightly warm colour and good contrast.
Out of focus highlights are nicely rendered and the resolution is maintained across the full width of the frame. The resolution is not stunning and this is an area where some of Canon’s older designs are starting to appear slightly dated in the digital age. The results, however, were very pleasant to the eye and the shortcoming will not be noticed on the majority of today’s cameras.

Canon claims two stops for the image stabilisation and I found no reason to doubt this. When shooting static subjects the IS is certainly a help, especially with this kind of focal length which is on the edge of where most people think they can hand hold.

Specifications

Focal Length & Maximum Aperture : 300mm 1:4.0
Construction: 15 elements in 11 groups
Diagonal Angle of View : 8º 15'
Focus Adjustment : Rear focusing system with USM
Closest Focusing Distance : 1.5m / 4.9 ft.
Filter Size for Canon 300mm f/4.0 L IS USM EFlens: 77mm
Max. Diameter x Length, Weight : 3.5" x 8.7", 2.6 lbs. / 90.0 x 221.0mm, 1,190g

Accessories
Canon front & back caps
Canon Hood
Canon Instruction manual
Canon soft case