The Canon EF-S 55-250mm f/4-5.6 IS STM Lens is a long-reaching
zoom lens that provides a 35mm-equivalent focal length range of
88-400mm, covering portrait-length to telephoto perspectives to suit
working with distant subject matter. Greatly benefitting this lens'
reach is the incorporation of image stabilization, which works to
minimize the appearance of camera shake by up to 3.5 shutter speed steps
to support handheld use in low-light conditions.
An STM stepping focus motor is also integrated into the lens' design to
provide smooth, quiet, and fast focusing performance that is
ideally-suited to video applications as well as tracking moving
subjects. The rear focusing system, high-speed CPU, and an enhanced AF
algorithm also contribute to quickened overall AF speeds. Full-time
manual focus is also supported to permit fine-tuning of focus even while
working in AF modes. Additionally, the front lens section does not
rotate during focusing to better facilitate the use of polarizing
filters.
The optical construction of the lens employs one ultra-low dispersion
glass element to help reduce chromatic aberrations and distortion
throughout the zoom range while also enhancing contrast and clarity.
Optimized lens coatings have also been applied to ensure color fidelity
by countering the effects of lens flare and ghosting.