Although the gentleman on the left was sitting on a folding chair, the car was slowing down to stop at a traffic light and the man on the right was walking at a brisk pace. This was shot through the window of a coffee shop, where I was enjoying a cup of coffee and an oatmeal cookie. The camera was already at my eye and prefocused when I released the shutter. I didn't notice until I was prepping the photo for posting that the pole in the foreground has a sticker that says "GET 1LL."
Most of the advice I've seen about street photography centers on how to answer the fear so many novice street shooters feel about taking pictures of perfect strangers in public places. Some photographers insist on being surreptitious. Others thrive on being in their subject's faces, often literally. Either side can come up with plenty of arguments why their approach is the right one (for them) and why a different approach is on shakey ethical ground. I suppose photographers like me who embrace both approaches risk double jeopardy and will surely burn in hell for their sins against humanity.
As I await my fiery demise I have a bigger challenge on my mind: how to bring a sense of order to the randomness of city streets. There's no rule that says you have to do this to produce great street photographs; it's just the way I like to work. And it ain't easy.
First of all, nothing stays still for long on city streets. Someone standing motionless will decide to move. Someone in motion will stop or change direction. It's not unusual for someone to move between you and what you're trying to photograph or even stop right in front of you. The same holds true for cars and buses. The direction and quality of light can also change, from direct, angular, and contrasty to indirect, soft, and shadowless. When the light changes so does the exposure.
Second, you the photographer have to keep moving too. Loiter in one spot too long, especially with a camera in your hands, and people begin to notice you. If they don't want to be photographed they may move on or turn their backs to you. If they're curious they may decide to engage you in a conversation, in which case you have to be polite and stop what you're doing long enough to respond.
Third is the fact that the moment when everything comes together may only last for the fraction of a second it takes for the shutter to open and close. A second sooner or later and the composition would be entirely different. You only find out afterwards whether it's a keeper or not.
If there's a "secret" to creating the appearance of order out of all this randomness it's the ability to react without conscious thought to the various elements gelling into a composition. Just as a boxer doesn't think about blocking a punch or throwing one when he sees an opening, your shutter finger should just "know" when to press down.
This approach to photography might seem the complete opposite to the more pre-planned, studied approach of studio and still life photographers. Whether planned or spontaneous, what these approaches have in common is the ability to recognize when everything is just right. Only you the photographer can decide when that moment is. It's then up to the people who view the resulting photograph to decide whether you were right.

Gordon, the reasons you list why it is so challenging is precisely why I love it so much. Both in the capturing for myself and the enjoying the work of others. When those elements come together, it can be magic.
Posted by: Chris Klug | May 08, 2011 at 10:44 AM
I love to catch those transient moments of order in between the bustle. But I like to engage people also. Sometimes I will take photos after asking, sometimes surreptitiously and sometimes in plain view.
One of my favourite photos began in hostility and ended with me charming the lady (Jacqueline) and getting her to agree to a photo. More a street portrait that what the purists consider street photography.
The point, for me, is not to limit myself. I may not ever achieve the degree of virtuosity of those who concentrate on one scheme, but I do have such fun :)
Jacqueline is here: http://photography.badlightgoodlight.com/365/e1132bf0
Posted by: Nikhil Ramkarran | May 08, 2011 at 12:51 PM
With regards to finding order in the chaos, I am often times saved by my ability to crop in post-processing. Sometimes all the elements are present to make a great photograph, and even if the overall composition is quite weak, a judicious crop here and there can sometimes mean the difference between a keeper and one that should be confined to the Trash bin. Personally I find it most difficult when walking around with a fixed lens (normally a 35mm or 28mm), and trying to capture something interesting across the road with so many distracting elements vying for attention.
Posted by: Syed | May 09, 2011 at 04:41 AM
It doesn't have to be anonymous street photography: I like capturing the occasional candid of friends during a social event.
I was going to suggest this might be a way to "ease yourself" into street photography but on reflection your friends can be your harshest critics! ;-)
[I rarely take true street photographs at home, but do so when travelling.]
Posted by: Sven W | May 09, 2011 at 04:53 AM