I've just become the proud owner of a Canon 400D + "Bigma". The problem I've got is carrying it about. It's not the weight but the Comfort and accessibility that's the problem. I would also like to accomodate my Nikon ED50 and tripod and bits & pieces. Am I expecting too much? Any advice would be gratefully received.
Thanks
If you are carrying both, then the tripod goes over your shoulder with scope attached. You need to make a shoulderpad so that it's comfortable.
There is no perfect answer for your other needs, so far as I know. The best - by a mile the best - sort of bag for carrying heavy camera gear is something like the Lowepro Specialist 85 (name from memory) which is a big, well padded, well-made bag with both waist and shoulder straps. Distributes the load evenly - much more comfortable than either method alone - and you can get at stuff instantly.
But for a lens the size of the Sigma 50-500, even that bag isn't really deep enough, not unless you reverse the lens hood. (I can fit my Canon 100-400 in like that, but not with hood attached - the Sigma will be abpout the same, I think.)
I think you need a third thing: probably a wide, padded belt with an attachment such that you can slip camera plus lens into it, holster style. I haven't seen one anywhere, alas.
I can carry my 30D with 400mm lens and my ED60 plus a spare lens and video camera in a Lowepro Nature Trekker, well worth the money I paid for it. Tripod fits onto attachement at the side of the rucksack.