Canon walkaround lens choices

Bob Atkins has a good review/comparison between a Canon EOS 5D with EF 24-105mm F/4L IS USM and EOS 40D with EF-S 17-85mm F/4-5.6 IS USM. I personally use the EF-S 17-85mm F/4-5.6 IS USM as my walkaround lens which I purchased after much delibration prior to leaving for my Everest Base Camp trek.

Friendly match in Texas Instruments, France
Canon EOS 400D, Canon EF-S 17-85mm F/4-5.6 IS USM, 108mm
1/400s @ F/5.6, ISO 400

My requirements from a general purpose walk around lens are:

• Wide enough for general landscape photography and group photographs (~ 28mm)
• Long enough for good portratits with out of focus background and for compressed landscapes (~ 100mm)
• Image Stabilization, because I mostly shoot hand-held and it's pretty difficult to carry a tripod or set it up on a hard trek in single digit temperatures
• Fast apertures, to avoid blur when shooting under low light conditions and for good out of focus backgrounds
• Good image quality, bokeh, low distortions & aberrations
• Light and small enough to carry around
• Price

I had purchased my EOS 400D body only, and bought the EF-S 18-55mm F3.5-5.6 IS at the same time to serve as my general purpose lens. The reviews were good to excellent for the (then) newly introduced lens, it was stated to be much better than the bundled non-IS lens in terms of optical quality. However, I found the 55mm (88mm conventional) too limiting and decided to upgrade before I left for the once in a lifetime trek to EBC.

Considering the 1.6 Field of View Crop of my EOS 400D, I was left with the following choices:

1. Canon EF-S 17-55mm F/2.8 IS USM
2. Tamron 17-50mm F/2.8 XR Di II
3. Canon EF 24-105mm F/4L IS USM
4. Canon EF-S 17-85mm F/4-5.6 IS USM

I am not including the super zooms from Tamron due to lack of image stabilization and image quality issues inherent with a super zoom. That said, I do own a Tamron 28-200mm XR lens from my film days that I still use with digital. I do not prefer Sigma lenses, since I have read of compatibility issues with Canon, however there are lots of Sigma on Canon users out there.

Train des Merveilles
Canon EOS 400D, Canon EF-S 17-85mm F/4-5.6 IS USM, 27mm
1/80s @ F/6.3, ISO 100

Considering my requirements, I arrived at the 17-85 after a process of elimination, mostly based on the focal length range supported by the zooms. The 17-85 is a well regarded lens, the complains about the lens are mostly the following:
- Not fast enough (F/5.6 @ 85mm)
- Distortion and Chromatic Aberration (CA) at wide angle

However, these were more or less what I could live with and/or work around (either by stopping down or correcting using software), so I decided to go in for the lens and has been more or less happy with the choice. I have shot with this lens in Nepal, Kudremukh and France amongst other places.

I recently purchased (yet to get in hand) the Canon EF 70-200mm F/4L IS USM lens that should nicely compliment the 17-85. Combined with a Tamron SP AF 1.4X TC, my lens range covers 17-280mm (27-448mm) with a max aperture of F/5.6 (1 stop loss with 1.4X TC) which I hope should be sufficient for most photographic opportunities.

The-Digital-Picture has a nice survey of most Canon general purpose lens choices.