Canon's improved L-series 24-105mm with better corner sharpness and nano coatings.
The Canon EF 24-105mm f/4L IS II USM launched in 2016 as the updated version of Canon's most popular L-series zoom. With a redesigned optical formula featuring an aspherical element, improved IS, and ASC nano coating, it addressed the original's corner softness and flare issues while maintaining the same beloved zoom range.
Optical quality is a clear improvement over the Mark I with noticeably sharper corners and better controlled chromatic aberration. The ASC coating alongside the existing Super Spectra coating provides excellent flare resistance. IS provides approximately 4 stops. Ring USM is fast and silent.
Canon EF mount only, 77mm filter thread. The RF 24-105mm f/4L IS USM for mirrorless is the successor. The Mark II represents the best version of this lens for EF-mount users. The original Mark I is cheaper but the corner improvement in the Mark II is worthwhile.
Good value used as the RF version has reduced EF prices. Check IS operation, zoom ring for the stiffness that affected some Mark I copies, and ASC coating condition. The Mark II is the definitive EF-mount standard zoom and worth the premium over the original.