It's OK to own every camera and lens ever made, but never OK to carry more than three lenses at any one time. Always carry as little as possible.
Never use a backpack; you can't shoot out of them and they carry too much. Backpacks are popular with newcomers and make a lot of money for bag makers, but experienced shooters don't use backpacks.
Photographers don't use backpacks because you can't get your gear out of them as you're shooting, and photographers don't carry that much gear at any one time. Photographers need to get to their stuff as they shoot, which means either stuffing lenses in pockets, a waist bag or a shoulder bag; never a backpack.
November 2008: I only use bags to get gear from one point to another. When shooting, I use a vest with many pockets because I can get to everything, no matter where I'm standing.
I never would use any sort of backpack, oddly popular among amateurs, since you have to lay it down on the ground to get anything. At best, backpacks get dirt in your gear, and in most places, like the middle of mud, climbing a branch or a stream, you have no place to put the bag even if you wanted to.
I've found it handy to add weight (ballast) to the rear pocket of my photo vest to improve balance between front and rear, Otherwise, loading only the front pocket pulls the vest forward, and chafes on the back of my neck, also pulling my neck out of joint and leading to stiff necks. I'll put gear I have no intention of using in the back pockets just to even out the weight.
March 2007: I'm a sucker for a bargain, so when I got a sale e-mail from Adorama advertising a big Domke waist bag at half off I bought TWO. It's the Anaconda-10, in black, for $59.95 here. They are overstock and regularly sell at $119.95. I got it: it's big and well made, but oddly seems like it may not have all the dividers I use, so I may need to buy a set of them for $32, which ought to cover both bags. I love waist packs, but for some reason they are getting harder to find.
I've been avoiding writing this article for years.
What could be more boring? I caved in to popular demand and wrote my tripod page years ago. Now bags? You keep asking, so here goes.
I keep my Nikon in a huge Tenba "Bear" P243 waist pack I got in 1999. I show it below. I'm unsure if Tenba still makes makes waist bags. Strangers don't recognize it as a camera bag. Strangers remark "Wow, that's the biggest fanny pack I've ever seen!" It holds my D70 or D200 body and 12-24 lens in the middle. There are four more long vertical slots for lenses. I jam my 80-400 VR (or 80 - 200), 24 - 85 mm and SB-600 flash in three of them. That leaves me one left over for a drink, macro lens or GPS. Each slot is so long I could jam two smaller lenses in on top of themselves.
It's easy to jam more gear into this pack than my wife thinks is safe for me to carry.
I never carry everything I own. I grab what I need for the day or trip. For instance, I might drop in my 105 mm macro if I think I'll need it. Only amateurs carry all their crap everywhere they go. I know I did!
I keep my 4x5 large format system in a vest I got at Banana Republic. Vests are great for dedicated photography because everything is on you and ready for instant access. Vests offer little if any padding, so they're suboptimal for taking off and throwing in a baggage hatch. I store my 4x5 system on a hanger!
Bags are far more personal than cameras. Get what you want, so long as its not a backpack.
Access is key. You need to get your stuff without having to take it off.
I prefer waist packs since they don't fall off and you can get everything. The top opens and it's all in your hands. You can run all over and it's not going to slip off. If you have a skinny butt it might slide down your pants, but that's not happened to me.
Next best for me is a small shoulder bag. They're easy to get in, but they are always sliding off your shoulder. You have to concentrate on not losing them, which means you're distracted from your photography.
I avoid backpacks. They're stupid. They require you to take it off and put it down on the ground just to get a filter. Personally I prefer the hiking backpack I picked out of the trash a few years ago (don't tell my wife: she's a clean freak!) because it has two mesh side pockets designed for drinks. I can jam a lens in either one so I can get it without taking it off.
Ken's Tenba P243 Waist Pack.
My D200 body and lens is in the center. I store it pointed down, but perked it up for this shot. My 80 - 200 AF-s is on the left. The 24 - 85 mm and SB-600 are out of the bag on and my D70 used to make this shot. The top flap stores my filter wallet on the inside. Inside the top of the top flap (not shown) I store cable releases, tripod plates, micro screwdrivers and spare lens caps. The front pocket holds my folded Lumiquest diffuser and batteries, flashlight and memory cards. Name tags are all over in case I forget it someplace.
This is based on my experience over the years. Things may change or have changed recently.
I love Tamrac. They're made in California to the highest standards. I have several Tamrac bags for different gear.
Tenba makes decent bags (I use a huge waist pack from 1999) and they're made in Brooklyn, New York.
Lowepro also makes great bags to the highest standards. I've used them for the past 25 years. The kicker about Lowepro is that their ads imply they are more of an environmental and human rights organization than the Sierra Club and Oxfam combined, but all of the four Lowepro bags I currently own is made in China. I think my Magnum 35 I bought in 1984 was made in Korea. It was stolen in 1992. My two Mini Mag P bags were bought in 1993 and used for my Mamiya systems. My Street & Field #4 lens bag is for my 80-200 2.8. I got my my Lens Trekker 600 AW in 1999 for my 400 mm f/2.8. Regardless of where they're made there are no better bags available. They are still like new after years of use. "AW" means all weather. I stay out of the rain, but my pals who don't tell me that these integrated pull-out raincoats really do work to keep your gear dry if you're stuck in a downpour.
A reader writes that he uses an old Winnie the Pooh diaper bag he stopped using after his kid became toilet trained. It's the last thing someone might want to steal.
Other photographers ship their cameras in coolers marked "Human fecal samples. Do not contaminate."
I keep different systems in different bags. I keep my Noblex in a small Tamrac waist pack. I stick my Mamiya 7 in a small tote. I have fewer bags than systems because I rotate different systems into them as I use them. I'm too cheap to buy enough bags.
You have to go to a retail store with your gear and try them in person. Unlike anything else you can't do it online.
I support my growing family through this website.
If you find this as helpful as a book you might have had to buy or a workshop you may have had to take, feel free to help me continue helping everyone.
The biggest help is to use these links to Adorama, Amazon, B&H, Calumet, Ritz, J&R and when you get your goodies. It costs you nothing and is a huge help to me. eBay is always a gamble, but all the other places have the best prices and service, which is why I've used them since before this website existed. I recommend them all personally.
Thanks for reading!