Canon EF 24-105mm f/4L IS II USM Lens Excellent Image Quality, Excellent Build Quality, Great Focal Length Range, Great Autofocus Speed & Accuracy, Image Stabilization, Weather Sealing The 24-105's focal length range slides toward the long end of the general-purpose range for APS-C body users, but it is still very well-loved by this group. Compare it yourself on the digital picture. RF STM vs EF L: 24mm: RF better. 50mm: EF better. 70mm: Match. 105mm: RF better. So, overall, I would say it is a downgrade on the image quality standpoint, but given you have a 26MP sensor, it's unlikely you'll really notice. The Canon EF 24-85mm f/3.5-4.5 USM is a very lightweight full-frame do-everything zoom for all Canon EOS digital and 35mm autofocus cameras. It performs especially well on the Canon 5D Mark III, which when a lens profile is loaded, corrects for falloff and lateral color, right in the camera. There are caveats, though, in that the RP is a poor choice for those looking to shoot video, and the native lens selection is lacking at this time. The EOS RP is available now at a price of $1299 body-only, $1999 with the EF adapter and a 24-105mm F3.5-5.6 lens, and $2399 with the native RF 24-105mm F4L lens. t2veW.