I'm about to embark on a basic lesson for manual shooters (for those of you wanting to learn how to use the manual settings on your camera).
First up is a lesson on shutter speed. The shutter speed is the length of time the light coming through the lens opening (or aperture) of your camera is allowed to stay on the film (or sensor) of your camera during any given exposure. These speeds are expressed in seconds or fractions of a second. i.e. 2, 1, 1/2, 1/4, 1/8, 1/15, 1/30, 1/60, 1/125, 1/250, 1/500, 1/1000, 1/2000, etc.
These numbers are read as two seconds, one 15th of a second, one 60th of a second, one 1000th of a second, etc. The smaller the bottom number is in a fraction, the slower the shutter speed will be. And vice versa, the larger the bottom number, the faster the shutter speed will be.
What it boils down to is this: A faster shutter speed can freeze the motion of a fast moving subject, and a slower shutter speed can blur that moving subject to give the impression of motion.
How is this useful to the average mom or hobbiest? Let's say your daughter is swinging on the swings at your local park, and you want to get a clean shot of the joy spreading across her face (while she is moving). Simply select a high shutter speed (at least 1/250 sec. or faster) to freeze the action and be sure to focus in on her face.
In contrast, to capture the motion of your daughter swinging (think a nice blurry arch), choose a lower shutter speed. Just keep in mind if you choose to use a shutter speed lower than 1/60 sec, you may want to mount your camera on a tripod to make sure the other elements in the picture remain sharp.
The following series of pictures illustrate how adjusting your shutter speed can make a dramatic affect over the feeling of an image.
In this first image, I started with a slow shutter speed of 1/6 of a second. You will see that the fan blades are blurred. It gives the impression that the fan is moving, but you can barely see the fan blades themselves.
I then switched my shutter speed to a slightly faster speed of 1/50 of a second. You still see the blur of the fans in motion, but you can now begin to see the actual fan blades themselves. The faster shutter speed is starting to freeze the action.
In this last image I set the shutter speed to 1/800 of a second - a very fast shutter speed. This stops the blades in their track and gives the impression that the fan is not even moving at all.
This is the power of shutter speed. Now you know how those professional sports photographers can get tack sharp images of a race car driving around a race track at over 100 miles per hour. Put this knowledge to the test and imagine the implications this will have for your son's soccer games. You can even get a great portrait of your child - without having to ask them to get off the swingset. They can have their fun while you have yours!
There's just one last (but very important) point to cover. You might have noticed that along with the changing shutter speeds in these three pictures, the aperture (or f-stop number) was also changed. That was necessary to make sure the exposure of each image stayed the same. Had I not changed the aperture the picture would have gotten darker and darker as I increased the shutter speed.
Does all this talk about aperture have your head spinning? No worries, I'll take on that beast next time. For now, just have fun with your brand spanking new knowledge of shutter speed. Go, grab the kids, head out to the park and freeze some of your own swing action! Enjoy!
