You Won't Miss Anything in a Crowded Room

This is one L lens that I am very proud of having owned. Unlike many other Canon L lens, this one is lightweight and easy to carry around, yet it has an extremely solid and substantial feel. Pick up this L lens, and you will immediately notice the built quality is very much better than cheaper, consumer grade lenses.

This lens can be used almost anywhere with a space limitation, like crowded room, and it will not miss any detail. Look through the camera viewfinder and you will note that its coverage will leave almost nothing out. If you are not careful with the picture composition, at 17mm ultra wide angle, you could even get your own 2 feet into the picture! It is also extremely useful for great landscape or scenery shots because of the increased perspective.

For an ultra wide angle lens, even at the 17mm setting, it gives minimum barrel distortion, thanks to its amazing linear correction capabilities. You can still notice a very slight curve when taking straight lines head on, but it is more tolerable than my EF24-85mm lens. Since I do not take very much architectural shots, this does not bother me.

What I liked best about this lens is the zoom and AF mechanism. Firstly, when zooming the lens, you rotate the zoom ring as in normal EF lenses, but unlike normal lenses, the lens barrel does not extend. This is great because it makes the lens more resistant to dust and moisture, hence it can be used more often outdoors. Also unlike normal EF lenses, the zoom ring is located at the rear end while the manual focus ring is in front.

Another great feature is the USM which is lightning fast and silent. A technical report I have read before, rates the AF speed of this lens from maximum to minimum distance (and vice versa) at 400m milliseconds! That's increadibly fast! This is a vast improvement over older DC motor AF drive, some of them taking several seconds to complete the task! Also, with USM AF, you can manually override the AF just before firing the shutter release - first you activate the AF by pressing the shutter release halfway, then manually turn the focus ring to achieve the desired focus, then release the shutter. This also cuts down on AF time and increases the shooting speed. Conventional DC motors would not permit manual override like this during AF mode.

Another advantage of this L lens is the maximum aperture of 2.8 required to activate all AF cross-sensors of the latest camera models such as the EOS 1V and EOS 3. Hence all L lenses with 2.8 or larger maximum apertures have a great advantage over normal EF lenses because AF action is faster and more precise.

Having said all the above, the real test of the lens is its optical performance. In spite of the slight distortion at 17mm, the optical performance is sharp and contrasty at all focal lengths. Most of my shots are keepers, even enlargements. It is truly amazing!

Unfortunately At 17mm with a filter attached on the front element, there is light fall off as the lens could "see" the edges of the filter. To overcome this problem, take off the front filter when shooting at 17mm wide - its that simple. Always keep the supplied petal shaped lens hood in place as that will offer great mechanical protection for the lens.

An alternative is the EF20-35mm lens, but if you like professional quality and have plenty of cash to spare, this is the best ultra wide angle zoom lens. It replaces several prime lens and yet produces outstanding results.