When I used to shoot with a Canon 5D Mark II, I had a whole system based on the Kata 3n1-20. That thing was superbly designed. It was a backpack that could be used as a sling for lefties and righties. It had a trolley system so you can use it as a roll-on bag. It even had a tripod/monopod holder that I regularly used. It was great. It was always ready. I could pick up and travel with me anywhere in a moment’s notice. It could carry the pro body, 5 lenses, all the chargers, miscellaneous gadgets, and even an iPad. But, fully laden, it weighed up to 40lbs.
The switch to the FF mirrorless Sony A7 has been a joy. Superior image quality at half the size and weight. With the smaller camera, I was also able to significantly lighten my gear. To quote Lotus cars founder Collin Chapman:
“Simplify, then add lightness”