The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon 18-200mm f3.5-5.6 IS and the Canon 28-200mm f3.5-5.6 for their suitability to various photography scenarios:
Size and Weight Comparison
The size of a lens is a crucial factor to consider when comparing two lenses. Canon 18-200mm f3.5-5.6 IS is the longer of the two lenses at 102mm. The Canon 28-200mm f3.5-5.6 with a length of 90mm, is 12mm shorter. Besides being longer, the Canon 18-200mm f3.5-5.6 IS also has a larger diameter of 79mm compared to the Canon 28-200mm f3.5-5.6's 78mm diameter.
The weight of a lens is equally significant as its external dimensions, particularly if you intend to handhold your camera and lens combination for extended periods. Canon 28-200mm f3.5-5.6 weighs 495g, 16% (100g) lighter than the Canon 18-200mm f3.5-5.6 IS's weight of 595g.
Filter Threads
Both the Canon 18-200mm f3.5-5.6 IS and the Canon 28-200mm f3.5-5.6 have the same Filter thread size of 72mm.
Below are links to the 72mm filters that we recommend you to consider for these lenses:
Lens Mounts
The Canon 18-200mm f3.5-5.6 IS has the Canon EF-S lens mount whereas the Canon 28-200mm f3.5-5.6 has the Canon EF lens mount. Some of the latest released cameras that are compatible with these mounts are Canon T8i, Canon 90D and Canon SL3 for the Canon EF-S Mount and Canon 1D X III, Canon 6D MII and Canon 5D MIV for the Canon EF Mount.
Focal Range
Canon 18-200mm f3.5-5.6 IS has a focal range of 18-200mm and
11.1X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
28.8-320mm when used on a APS-C / DX format camera.
On the other hand, the Canon 28-200mm f3.5-5.6 has a focal range of 28-200mm and 7.1X zoom ratio . When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 44.8 - 320mm.