After testing dozens of bags and backpacks from all the major brands, I can say that I have found the perfect messenger bag for my photographic equipment. It's black, discreet, doesn't look like a photography bag, is lightweight, has a rear opening and a magnetic opening and closing system, which is secure and quiet. It fits my XT4 with the Tamron 17-70mm with the lens hood on, plus the 50-140mm or 70-300 and there is still room for another lens/flash.
I'm sure it's the perfect bag!!!!
I'm talking about the Think Tank SpeedTop 15. https://www.thinktankphoto.com/products/speedtop-15