For years I battled a heavy case with 2 cameras - one for wildlife and one for landscape. Changing lenses in the field was also difficult and requires more time than is available for sudden wildlife shots, especially flying birds. I tried backpacks, but trying to get a camera out in time to catch wildlife was difficult. Now, I carry two cases criss cross one over each shoulder. One has the A1 with a 70-300 mm lens and sometimes the 100-400 mm lens and a few accessories for wildlife. The other case has the A7RIIIA with 24 mm lens and a water bottle for landscape. With this setup, I find myself using both cameras more often. I use the OP/TECH USA S.O.S. Curve Strap (Black) # 0901312 adjusted to 48" length.