The Canon R5 Mark II’s IBIS combined with the RF 15-35mm f/2.8L IS USM provides up to eight stops of combined stabilization according to Canon’s specification. In practice, on a full-frame sensor at 15mm, that means a stationary subject can be photographed sharp handheld at shutter speeds as slow as 1/4 second by a photographer who has learned to hold still. This is not theoretical. It works. The technique is breath control and body mechanics.