Canon's budget full-frame standard zoom — 24-105mm with IS and STM motor but slow variable aperture.
The Canon EF 24-105mm f/3.5-5.6 IS STM launched around 2014 as a more affordable alternative to the 24-105mm f/4L IS USM. It trades the L-series build and constant aperture for a lighter, cheaper design with STM motor for smooth video AF.
Optically adequate — sharp in the centre but softer than the L version, particularly at the edges. The variable f/3.5-5.6 aperture is slow by 24-105mm standards. IS provides approximately 4 stops of stabilisation. STM motor is smooth and quiet — good for video.
Canon EF mount with 77mm filter thread. Approximately 525g — lighter than the L version. Full-frame coverage. Plastic barrel with metal mount. No weather sealing. Minimum focus distance 40cm. Commonly bundled with the EOS 6D Mark II.
Available used cheaply. The 24-105mm f/4L IS USM is much better in every respect except weight and price. The variable aperture and slow f/5.6 at 105mm are significant compromises. Only worth considering as a budget full-frame walkaround where weight matters.