Canon Rumors reader Ivan sent in a mockup that shows the size difference between the RF 24-105mm f/4L IS and the revolutionary RF 28-70 f/2L. The latter is definitely going to be a big lens, but maybe not as big as we originally thought.
The Canon RF 24-105mm f/4L IS has the following measurements:
Size: Approximately 83mm (3.26 inches) x 107mm (4.2 inches)
Compared to the EF 24-105mm f/4L IS II 83mm (3.26 inches) x 118mm (4.64 inches)
Weight: Approximately 698g (1.5lbs)
Compared to the EF 105mm f/4L IS II 795g (1.75lbs)
As with any mockup such as this, it may not be 100% accurate.
RF 24-105mm f/4L IS USM & RF 28-70mm f/2L USM Size Comparison // Click for larger