The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon 75-300mm f4.0-5.6 III USM and the Canon 55-250mm f4-5.6 IS II 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 USM is the longer of the two lenses at 122mm. The Canon 55-250mm f4-5.6 IS II with a length of 108mm, is 14mm shorter. Besides being longer, the Canon 75-300mm f4.0-5.6 III USM also has a larger diameter of 71mm compared to the Canon 55-250mm f4-5.6 IS II's 70mm 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 55-250mm f4-5.6 IS II weighs 390g, 18% (90g) lighter than the Canon 75-300mm f4.0-5.6 III USM's weight of 480g.
Filter Threads
Both the Canon 75-300mm f4.0-5.6 III USM and the Canon 55-250mm f4-5.6 IS II have the same Filter thread size of 58mm.
Below are links to the 58mm filters that we recommend you to consider for these lenses:
Lens Mounts
The Canon 75-300mm f4.0-5.6 III USM has the Canon EF lens mount whereas the Canon 55-250mm f4-5.6 IS II has the Canon EF-S lens mount. Some of the latest released cameras that are compatible with these mounts are Blackmagic URSA 12K LF, Z CAM E2-F6 II 6K and Z CAM E2-S6 II 6K for the Canon EF Mount and Canon T8i, Canon 90D and Canon SL3 for the Canon EF-S Mount.
Focal Range
Canon 75-300mm f4.0-5.6 III USM 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.
On the other hand, the Canon 55-250mm f4-5.6 IS II has a focal range of 55-250mm and 4.5X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 88-400mm when used on a APS-C / DX format camera.
