November 2015: This is my current on-the-go photo gear in a Lowepro Format BP 150

42MP Sony a7II w sling strap and Sony e PZ 18-105G zoom (APS-C 18MP) attached
FF Sony Zeiss FE 16-35ZA zoom (lower left). FF Sony SAL 70-300G A-mount with LA-EA3 adapter.
FF Minolta 50mm f1.7 A-mount with LA-EA4 adapter (upper right).
charger...spare camera batteries... spare SD cards... small flash w/spare batteries...misc stuff

For reference, this backpack is only 9 inches wide and 8 pounds. Under half the weight and almost twice the pixels of my Sony a850-gear bag!

There also exists a 'sidecar' lens case w/ FF Samyang 14mm & Fotodiox A-to-E mount adapter