There's a discussion on the new Pentax forum about the Pentax K10D being suitable for professional work. This led people off on a tangent about what bodies are suitable for pro work. And I started to wonder what really is necessary for professional work - especially since there are some many kinds of professional photography.

I have cameras at both ends of the spectrum - a Digital Rebel XTi / 400D and an EOS 1D. I'm using both cameras for pro work but they each have their own place. For most work, I'd prefer to use the XTi, since it's smaller, lighter, has more resolution, and better high ISO performance. But if I need the best speed and auto focus accuracy, I'm absolutely going with the 1D. The XTi doesn't even come close.

So that begs the question - what constitutes a "professional" SLR body? Some of the traditional things are flash synch speed - 1/250th second is standard and 1/200th is the minimum. The number of exposures that the shutter is rated for is another regular professional spec. If you're shooting thousands of images a day, you don't want a shutter that will lock up after 10,000 actuations. Build quality is another typical professional concern. Someone who's using their camera all day, 5-7 days a week in questionable conditions might be concerned about a camera that doesn't have some heft to it.

But, the best photographers will get the job done with what they've got. Some photographers care little about their equipment. So what is it that makes a camera worthy of "professional" use? Or is it just marketing? What do you think?