The Canon 24-105/4L IS lens is reasonably high quality, reasonably
fast, reasonably wide range, and reasonably light. It is designed for
the latest generation of full-frame digital SLRs such as the
Canon EOS 5D, (compare prices) (review). If you want a high
quality wide-to-telephoto zoom and plan to take photos from
a moving car, boat, or airplane,
buy one right now from amazon.com, (compare prices).
Producing a high quality 4:1 zoom lens is very challenging, but the
"L" in "Canon 24-105L" assures you of professional quality images,
rugged construction, and substantial weather-proofing. The 24mm wide
end is wide enough to be dramatic and the 105mm telephoto end is long
enough to provide a significant flattening effect for portraits. With
the light weight achieved by designing for an f/4 rather than an f/2.8
aperture, the 24-105/4L is a great travel lens.
Image stabilization and its discontents
Is f/4 with image stabilization just as good as the f/2.8 on most
professional zooms or the f/1.4 on a prime lens? Click on the image
at right, captured at 1/30th of a second. The image stabilizer
ensured that the effects of camera shake were minimized. The
paintings and the text on the wall are not blurred. However, the
image stabilizer will not stabilize the motion of objects within the
frame. This could have been a fun photo with the guy at right staring
into the camera. At 1/30th, though, his walking motion renders him
blurry. With a 50/1.4 lens, the shutter speed could have been a
motion-stopping 1/250th of a second.
If you don't need the zoom and love to take photos in dim light,
consider the Canon EF 50mm f/1.4 USM, (compare prices) (review). It is three f-stops
faster than the 24-105/4, and, despite the lack of image
stabilization, is more useful in low light.
This is an EF lens, casting an image circle large enough to cover a
24x36mm piece of film or the sensor in Canon's more expensive
"full-frame" digital SLRs. The camera will work fine on a
small-sensor body, but you will be carrying around more lens than you
need and the focal length will be a "slighty-wide-to-telephoto" range.