Here’s another shot from Kensington Market. If you notice, my subject is pretty sharp but the background is in movement, blurred in fact. That’s because I shot this from the hip while moving along at the same pace as my subject. The shutter speed was relatively fast (1/80th of a second), which is why I think my masked man is sharp, but not so overly fast that the background is also sharp. For that I would have needed a shutter of around 1/250th or faster. Since I shot at F8 I could have opened up the lens by two stops to F4 (F8-F5.6-F4), which would have doubled by shutter speed twice (1/80 to 1/160 to 1/320th). The problem with that is two fold: 1. not only would I have lost all sense of movement, which is what I believe makes this shot dynamic and somewhat interesting and better draws your attention to my subject, but 2. I would have also risked mis-focusing on my subject and having him out of focus due to the shallow depth of field with comes with shooting at F4. At F8 my focus area is deep enough that even if I’d missed him and hit the person behind him, he’d still be in focus. For street photography with a full frame camera, F8 to F11 works well, especially if you shoot from the hip, as I’m oft to do. I should point out that if I wanted to maintain my F8 aperture, yet increase my shutter speed by two stops, another option would have been to increase my ISO by two stops (ISO 200 to 400 to 800). At ISO 800 my shutter speed would be around 1/320th and my aperture would remain unchanged at F8. But higher ISO introduces unwanted digital noise into the shot, which is why it’s always better to keep that ISO low.
Now, had I been standing still and looking through the viewfinder, I might have shot wider, like F5.6, since there’d be no risk of missing my subject. But the fact is, this is not the kind of shot you can get standing still. With a shutter fast enough to freeze him (1/250th), all the background people would have been frozen, too. If I shot with a slow shutter speed, like 1/30th, both him and the people in the background would have all shown signs of movement. The only way to freeze him and yet still capture the movement of the people behind him is to walk along with him as I shot.
Now, with all that said, let me also say that this capture was more luck than skill. I wasn’t really paying attention to the camera settings. I just happened to see him and shoot him without thinking. It was a moment and then the moment was gone. No time to think or adjust the camera. Bottom line: You see something worth shooting, you shoot it. You don’t stop to adjust the settings, unless your subject is just standing there and you have time to kill. With that in mind, it’s hugely important to continually check your settings so you know where your camera’s at when you do come across a dynamic, highly fluid situation.