Changing the Autofocus Button on Canon Digital SLRs
A while ago, I noticed that my friend Jonathan seemed to have a special setup on his Canon 5d—he wasn’t using the shutter button to auto-focus his subjects. He had decoupled the auto-focus from the shutter button and instead used a button on the back of the camera. I tried it; I loved it.
What’s the point of doing this? It allows you to keep shooting regardless of what’s going on with the focus motor. I find that it’s really helpful if you’re shooting with a reasonable depth of field and the subjects are moving around a lot (parties, street photography, people in general). It’s a much faster manual workflow and it takes only a short period of shooting before it feels very natural.

To configure this is easy, but I don’t recommend your camera manual—it’s very obtuse language. Instead, check out: Canon Digital Learning Center - Back-Button Auto Focus Explained. On a 5d Mark II, my FN IV Custom Functions (Operations / Others) have the following settings: #1 is set to 3 and #2 is set to 1.
Happy shooting.
Sometimes, you wonder if you’re getting funny glimpses of coming changes in technology. In this case: I wonder if Apple is really pushing for a convergence of messaging.
SMS is one of the most profitable parts of the telecom carriers’ business—it’s the closest thing that there is to a form of universal push messaging, but they’re so greedy that they’re hesitant to open up SMS messaging in ways that would allow more innovation. So it looks as if software people are starting to end run around them—between Blackberry supporting their own messaging system (which, I hear, is a lifesaver for international long-distance relationships), Twitter direct messages for the webheads, and now Apple supporting a special iPhone type in Contact profiles and always showing the choice to short message an email address. I wonder if Apple is planning to take their App notification structure and have their own messaging layer?
Convergence of telecom and web services is happening in a lot of places beyond the client software. From Jamie Siminoff’s coming GRID service which will mix voice and SMS messaging on the same ten digit phone numbers, to Twilio’s beta of a similar offering, to Clickatell which offers that service everywhere but the US, to Google Voice, to Ribbit, to my old company—Mobile Commons.