When I shoot, even casually, I often carry more than one camera body. When I’m working, I always carry more than one body.
This is a pretty old practice, especially for news and sports photographers, going back at least to the early days of the single-lens reflex camera. If you can find old news or sports photos that include photographers in them, you’ll see this. For example, in Hans-Michael Koetzle’s terrific book, Photo Icons, volume 2, there’s a photo by a great German news photographer Barbara Klemm, showing Leonid Brezhnev (Soviet Communist Party Chair at the time) meeting German Chancellor Willy Brandt in Bonn. The photo mainly shows the principals and their translators and advisors huddled together to negotiate. But in the near background, there’s another photographer, shooting the back of Brezhnev’s head. He’s holding one Nikon with what appears to be a wide lens, and he has two other Nikons hanging around his neck, one of which has a telephoto lens.
I found Klemm’s image on the Web. (Google Images never ceases to amaze.) Notice the photographer in the back on the left.
Anyway, carrying two or more bodies is still common, or at least not uncommon. I routinely carry two cameras with me, and sometimes three. This was true when I was working an event in the past, where I’d carry a wide, fast zoom on one camera and a tele, fast mid-range or longer-range zoom on the other. Now that I work mostly with primes, I carry more than one camera even more than I used to, because I would prefer not to change lenses. For example, I might carry the K10D with a Sigma 28 f/1.8 and the K20D with (perhaps) the Pentax 70 f/2.4. This gives me a choice of focal lengths, which is exactly what the old news photographers wanted when they carried more than one body.
Carrying more than one body also means that I’m less likely to be stopped cold by equipment failure. If one camera were to fail – and it has happened – I have the other camera right there, in my hand or at least around my neck, turned on and working. I can’t apologize to the couple and the minister and ask them to pause the wedding ceremony for one minute while I get the backup out of my bag!
(This post is a revised version of a reply that originally appeared in the pentaxforums.com discussion site.)