Rough Guide to Bags - Factors to Consider
Camera bags are made from a variety of materials. Natural fibres (eg. canvas, cotton, leather) are favoured by the likes of Domke, Billingham, and National Geographic, while man-made hi-tech materials like ballistic nylon are preferred by brands such as Kata, LowePro, Tamrac and Crumpler. The latter generally offer higher performance - lighter, better water-resistance etc - but consider that traditional bags have survived use by Amazonian explorers and Vietnam war correspondents, so they should be able to cope with the odd downpour on the Peaks.
The more padding a bag has, the more protection it offers, but the heavier and more rigid it becomes. Brands such as Kata are at the forefront of developing innovative workarounds such as aluminium ‘spines'. A bag's water-resistance is very important. Look out for exposed zips that can let in water, or flaps that don't offer a good seal. Some bags come with a waterproof cover, like a big shower cap, which you can pull over the bag if it rains.
How big a bag do you need? You may have lots of gear, but do you want to carry all of it with you? The type of photography you do will influence the bag you'll need. Into sports or wildlife? You'll need one that can hold a big telephoto lens. Travellers, on the other hand, will want something smaller.
An uncomfortable bag will kill your desire to go out and take pictures. A bag that sits too low, a strap that digs into you, a harness that cuts into your back - in some cases this is due to bad design, but it's also because we're all different shapes. Try your bag out before buying - ideally with weight in it.