I'm traveling from the US to Paris, Venice, Florence and Rome for a few weeks this summer with the family. I'm keeping my kit light – E-M1, 12-40/2.8, 14-150, and either 17/1.8 or 25/1.8 for evening. Also bringing a Canon G7 X or Stylus 1 as a backup/supplement. When out for the day sightseeing in these cities, is it best to travel with a camera bag, or am I fine with the camera on a sling? I plan to only head out with one of the zooms and one of the primes, depending on what we're doing that day. I never use a bag while traveling in the US, and will have access to my spouse's small backpack for the extra lens. I have that small Olympus soft case for the E-M1 I can use, but it rarely seems worth the trouble. http://www.getolympus.com/us/en/om-d-e-m1-soft-camera-case-cs-42sf-black.html Thanks.