Thanks all for sharing. Yes, i was planning to switch fom backpack to shoulder bag for quicker, easier access of gears. Saw some bags that promise to carry loads of gears, so thought it is a good idea. Having heard your valuable pointers, I will reconsider the approach. With my average built and not-so-strong back, it is probably a really bad idea to switch.
I will check out the options that you have suggested and see what could work for my needs. Thanks again.
i am not sure about you but i have multiple bags for different patterns of usage. i have namely 2x backpacks(Lowepro Fastpack 250, Thinktank Streetwalker Pro) and 2x sling bags(Crumpler 7 Million Dollar Home, Billingham Hadley Pro).
i pack according to what i wanna shoot. for my normal weekend landscapes shooting, i will go with the Thinktank, reason being its high quality build which protects my gears well. not to mention it(actually all backpacks) leaves both my hands free to do what i need to do. with my liberal space setup, it typically holds my 7D + BG-E7 + 10-22 + 70-200L + tripod + gorillapod + filters + accessories + water bottle + nitty gritty stuffs. the Lowepro holds more or less(perhaps a little less) the same stuffs but the paddings are not as good as the Thinktank.
if i wanna shoot streets(which i seldom do), or i just want to carry my 7D + 2 lenses + 580EXII, i will go with the Crumpler. it holds my gears pretty well and i can access them easily. to be honest, i have tried packing my 7D + grip + 10-22 + 17-55 + 70-200L + 580EXII + accessories + nitty gritty stuffs into the Crumpler before. sure the bag can contain everything, albeit the tight squeeze, but i pretty much had an aching, beaten shoulder and back at the end of the day. it is not fun to carry such combined weight on a single shoulder, trust me on this. somemore i did it for 5 consecutive days when i was on free and easy vacation in Hong Kong, travelling via public transports and walking all day long.
now down to my last bag - the Hadley Pro. this one bag is purely reserved for my m43 gears, namely E-M5 + 12-50 + Panasonic 20/f1.7 + kit flash + accessories. put all these in and i barely fill half the bag. the Billingham can also carry my gripless 7D + 1 lens + 2nd lens/580EXII but i avoid using this bag for my DSLR as i typically cannot sufficiently pack what i need for my 7D.
for travel, i will carry my Thinktank on my back then pack my Crumpler into my luggage. then when on location i will pack the stuffs into my Crumpler according to the day's itinerary. or the other way is pack some of my stuffs into the Thinktank and ask my father/bro-in-law to carry it, then i will have the 7D + 10-22 and E-M5 + 20/f1.7 in the Crumpler. then repack according to places of visit again.
so yeah, just sharing with you how i use my bags. i feel as a serious hobbyist, one should have at least a backpack and sling bag to cater to different shooting needs.