The 24-105mm focal length range almost seems to be the default for Canon standard zoom lenses and there are already two in the RF system, the RF 24-105mm f/4 L IS USM and the entry-level 24-105mm Having f/2.8 in stead of f/4.0 at typical portrait focal lengths is huge. It is, and having 105mm instead of 70mm is also a godsend - at least for my needs. If I had the 24-70/2.8 + 70-200/2.8 combo I would indeed still plan on upgrading to the 24-105/2.8 even though there would be overlap, as it would still save on lens changes and/or body swaps. Usable Aperture Range: I often just set it either at F4 or F8 and have no issues. Low light performance on the Canon R6 is actually quite nice, you can probably expect this lens (in this setup) to act more like a F2.8 lens on older DLSRs when low light performance is considered. Bodies Used On: Canon R6, Canon R5. Source: MPB il0tf.