davidrb wrote:
Nasser, you raise a great question. The 24-105mm f/4.0L IS is one of Canon's tried and true "tanks". The lens is a real workhorse for many photographers, both pro and non-pro. It is a great landscape lens b/c of it's focal range. The lens is weather sealed when a front filter is screwed into place. The f/4.0 is favored b/c it stays at that aperture at all zoom lengths. This lens does extend when zoomed. Canon thinks so highly of it they added it so some pro-line cameras as a kit lens. It is considered a member of the "L" series, a top-of-the-line series. It will include case, caps, and hood. The 24-105mm f/3.5-5.6 IS is a new-comer to the Canon line. It is not to be considered better or worse than it's predecessor, it is just different. Notice the f/ settings, they range from 3.5 to 5.6. Canon spec sheets can show you at what focal lengths the changes occur. It may require re-focusing as you change zoom. This lens sells for less b/c it is not built as well, the glass in not the same, the focus situation effects the operation. Hood, and case are not included. The market for this lens was strong enough to cause Canon to bring to market a newer version. Either one would be a good addition to your kit. GL
Nasser, you raise a great question. The 24-105mm ... (
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My Canon 24-105 f/4 L USM lens barrel DOES extend when zoomed out to 105.