The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron AF 18-200mm f3.5-6.3 XR II LD and the Canon 75-300mm f4.0-5.6 III 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 75-300mm f4.0-5.6 III is the longer of the two lenses at 122mm. The Tamron AF 18-200mm f3.5-6.3 XR II LD with a length of 84mm, is 38mm shorter. On the other hand, the Tamron AF 18-200mm f3.5-6.3 XR II LD has a larger diameter of 74mm compared to the Canon 75-300mm f4.0-5.6 III's 71mm 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. Tamron AF 18-200mm f3.5-6.3 XR II LD weighs 398g, which means it is 82g (17%) lighter than the Canon 75-300mm f4.0-5.6 III which has a weight of 480g.
Filter Threads
The Tamron AF 18-200mm f3.5-6.3 XR II LD has a filter size of 62mm whereas the Canon 75-300mm f4.0-5.6 III has a 58mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 62mm filters that we recommend you to consider for the Tamron AF 18-200mm f3.5-6.3 XR II LD:
And these are the 58mm filters that we recommend for the Canon 75-300mm f4.0-5.6 III:
Lens Mounts
The Tamron AF 18-200mm f3.5-6.3 XR II LD has the Nikon F (DX) lens mount whereas the Canon 75-300mm f4.0-5.6 III has the Canon EF lens mount. Some of the latest released cameras that are compatible with these mounts are Nikon D3500, Nikon D7500 and Nikon D5600 for the Nikon F (DX) Mount and Blackmagic URSA 12K LF, Z CAM E2-F6 II 6K and Z CAM E2-S6 II 6K for the Canon EF Mount.
Tamron AF 18-200mm f3.5-6.3 XR II LD is also available in the Canon EF , Sony Alpha and Pentax KAF mounts.
Focal Range
Tamron AF 18-200mm f3.5-6.3 XR II LD has a focal range of 18-200mm and
11.1X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
27-300mm when used on a APS-C / DX format camera.
On the other hand, the Canon 75-300mm f4.0-5.6 III has a focal range of 75-300mm and 4.0X zoom ratio . When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 120 - 480mm.