UPDATE - OCTOBER 15, 2008

This update is going to read pretty much like the last two pages, so if you are hoping for some bad news... sorry. We are back from a 10 day trip to New England for the fall colors, and the Canon 24-105mm F4 L IS got a solid workout.

Zoom lenses such as the Canon 24-105mm L F4 IS tend to have a rough time on the photography forums. When shooting subjects close to home it is easy to use a prime instead of zoom. Odds are you know the location, you know the light, you have a good idea of the subject matter and shooting conditions. So people go to their favorite (close to home) shooting spot, take some snaps with their new Canon 24-105L and compare results with those from their favorite prime. Then they go on line and complain about the zoom because it is not as sharp as they expected. In my opinion the Canon 24-105L’s value becomes readily apparent when traveling and facing more unknowns than knowns. And vacations are full of unknowns.

During our trip through New England I intended to use the Zeiss 50mm F2 Makro-Planar ZF non-stop. On paper it was great plan - the prime had a faster aperture, so more control over DOF and potentially more creative compositions. The ZF is as sharp as they come. The ZF is light, relatively compact and really does not need a lens hood because the front element is deeply recessed. And with Live View, manual focusing would be easier. On paper it all looked good. By the end of the first day the Zeiss 50mm F2 ZF was back in the bag and the 24-105L was essentially welded to the 1Ds Mark III.

UTILITY VERSUS OPTICAL SUPERIORITY

The best lens is the lens you use. We can spend thousands of dollars on the best primes and cherry pick the ultimate lens dream-team based upon their technical merits. But, if those lenses spend most of their lives sitting in the camera bag, then where is the value? I could have shot may of the images with Zeiss 50mm F2 Makro-Planar ZF, but here is why that did not happen:

1. •Unknown shooting conditions: This was our first trip to New England and I had no idea what to expect. We were stopping at 5 to 10 locations per day. Some stops were small towns, some were trails, views, historical landmarks or just a spontaneous moment. The pictures were 28mm, then 80mm, then 45mm, then 105mm, etc. Had I been using primes, I would have been changing lenses 50 to 100 times per day - and carrying alot of extra gear. Some of locations were rainy and windy, so lens changes were not feasible.
   

2. •Image Stabilization (IS):  I do not think it is possible to overstate the value of IS. With the 24-105L image stabilization buys a 3 to 4 stop advantage. In October on the east coast the light is not as bright as the summer. Getting enough light for F8 or F11 is a stretch. Bumping ISO helps, but that also reduces dynamic range. I was also shooting with graduated filter and CPL’s - both of which further reduce light. IS allowed to shoot landscapes at small apertures (ie - F8, F11) handheld. Dragging a tripod in and out of the car at every stop would have been a pain in the a.....
   

3. •Portability:  A 50mm prime is smaller than a 24-105mm zoom, but the zoom weighs less than carrying 24mm, 50mm and 100mm lenses. We did alot of hiking and being able to carry just one lens translated into less bulk and other smaller conveniences such as only having to carry 77mm filters and one lens hood.
   

There are many images I wish I had taken with a prime, but hindsight is 20-20. The only advantage of the prime per-se would have been a sharper image - maybe. IS goes a long way and there were plenty of images at 70-105mm with shutter speeds of of 1/20 or 1/30. With a prime the shutter speeds would have been 1/100 or faster to guard against lens shake, thus shot with a faster aperture, thus less DOF. Or possibly higher ISOs, and then the images would not have held up as well during the post-processing.

When used with the Canon 1Ds Mark III the Canon 24-105L does lack resolution. Whether it is the 1Ds Mark III’s AA filter, the DigicIII in-camera processing or the lens - the images could be sharper. The softness is most noticeable at the tele end. The 24-105L’s resolution is pretty good in the 35-50mm range. Overall, 13x19” prints would be fine. 17x21” may look slightly soft under close examination at about 18 inches. At 24x30” I would definitely would want to use a prime if the composition contained a large amount of fine details. Most of my prints will be in the 17x21” size, so the 24-105L should be fine.

As sensor densities increase, I hope Canon updates the 24-105L to keep pace. With the Canon 5D Mark II shipping in several weeks, there will be a lot of chatter on the forums with photographers looking for walk-around zooms that can maximize the 5D Mark II’s sensor. I think the Canon 1Ds Mark III pushes the 24-105L to its limit, so I expect the 5D Mark II will do the same. On the other hand Canon has been bundling the 24-105L in the Canon 5D kits and effectively selling the lens for around $800, and at that price it is really hard to complain about the 24-105L.

Overall I give the 24-105L a solid “A-” on its report card. In a Mark II version I would like to see some resolution improvements and possibly extending the range to 135mm. More images from Boston and New England here.