In the Lowepro Photo Runner 100, I was able to fit my 1DS mark 3 and a couple of lenses in there. I did record some audio with the Tascam DR-40 which I stored in an S&F pouch attached to the Photo Runner using one of the SlipLock loops.
The Lowepro Photo Runner 100 was the perfect choice for me since I was able to fit a couple of lenses, my passport, iPhone, pen, hand sanitizer and Giottos blower all within arms reach. During my shoots, I used the bag as a beltpack on my waist because this allowed me to have quick access with just a pull of a zipper and not placing it on the sand. Having the bag on my waist, freed up my shoulders and hands, which made it easier for me to direct during the shoots. When I wasn't shooting, I used the provided shoulder strap that I kept tucked in the back when I was not using it.