A convenient lens for a second camera is the a6400 paired with the A7III. Compact and lightweight zoom for close-ups, great for reportage video, ideal for weddings, except for aperture. At a banquet, either put a lantern or change the lens. Easy setup of the camera, lens and stabilizer can be taken smaller. A pleasant thing to use, for certain purposes an excellent option.
Canon EOS SLR Camera Lens EF 24-105mm f/4 L IS USM
124 Review
Canon EF 40mm f/2.8 STM Lens - Fixed Black (6310B002) for US Cameras
76 Review
Nikon 35mm f/1.8G Auto Focus Lens for Nikon DSLR Cameras - Black (Model 2183)
125 Review
Canon EF 50mm f/1.8 II Fixed Lens - Discontinued by Manufacturer
93 Review