Micro four thirds (u43) cameras are generally much smaller than DSLRs, and even quite a bit smaller than full-frame MILCs (mostly because the lenses are smaller

Micro four thirds (u43) cameras are generally much smaller than DSLRs, and even quite a bit smaller than full-frame MILCs (mostly because the lenses are smaller). Their optical performance isn't as good a full-frame DSLR, but they are close enough to be a good substitute. I have a u43 Olympus E-M5 III, and also a FF Panasonic S5, and although the Panasonic is "better", the Olympus is so much easier to stuff into a bag that it's still my camera of choice most of the time. I should note that not all u43 cameras are small - Olympus / OM have a top-end "1" model that is large and clunky. But the "5" and "10" models are nice and compact. I think the Panasonics and the Olympus / OM PENs are pretty small too. There is then a useful range of lenses that lets you trade off performance, zoom range, and size; there are great, tiny primes; decent, tiny zooms; and great, chunkier zooms. In particular, the Pansonic Lumix G 12-32mm lens is 24 mm long. I can put that on my E-M5 and carry it in a jacket pocket. People have managed to take photos with it: https://www.flickr.com/groups/vario1232f3556/pool/ https://www.flickr.com/groups/vario1232f3556/pool/