Limited to F4.5 at the wide angle, and even with image stabilization you know it's nowhere near a low light lens. Comparing it to larger, more expensive lenses isn't entirely fair as it can't match the image quality of say 70-200L and the L can't match this lens in terms of size and comfort. However, it's sharp enough and works adequately with my EOS M3 camera. If you need a longer lens than a standard lens and don't want to mess with an adapter or a large glass, Canon's mirrorless cameras give you very few options. Aside from being slow, the only two real complaints I have are that it doesn't feel as solid as other lenses in Canon's mirrorless range, and for some reason Canon has opted for a plastic lens mount for it , which makes it even cheaper. Eventually it arrived in a white box with no paperwork, leading me to believe it was a gray market lens or was removed from the kit. I have many lenses that came this way but they should tell you in advance.