most people know that the shutter of the camera is what opens and closes when you take a picture. we'll start with this component because it's the easiest to understand of the three main contributors to your photo capture (the other two being ISO and aperture). shutter speed is measured in seconds, although more commonly in fractions of a second. the shutter speed can affect a few things in a photo, but in isolation its main impact is on the 'fluidity' of the picture. the easiest way to illustrate this is with some examples.
this first photo is taken with a shutter speed of 1/60 of a second, f/5, ISO 250, and with on-camera flash. for this post we're only interested in the shutter speed parameter. notice how the water looks pretty sharp and 'frozen in time'.
this second photo was taken of the same exact drip stream of water, but with a shutter speed of 1/30 of a second, f/11, ISO 1600, and no flash. the same flow of water now looks more fluid, almost like a complete stream. the use of the flash makes a difference, but the concept is illustrated the same.
what's the deal? why does it do that? when the shutter snaps quickly (generally anything faster than 1/100 second) you typically get a clean picture that doesn't have any blur. most things don't move very much in 1/100 second. when you shoot with a shutter speed down in the range of about 1/30 second all the way down to multiple seconds, you are essentially taking a video that keeps overlapping onto the same photo. lots of things can move in a few seconds, even lazy people. as long as the shutter is open, it's letting light in to hit the sensor and recording it.
"matt, my point-and-shoot camera pictures keep coming out blurry and i don't know what's going on, plus i don't care about all this technical stuff. how do i fix it? ps - i love your blog." well first off that's very flattering. secondly, chances are that your friend, mr. shutter, is too slow. the simplest and most casual way to remedy that problem is by turning your flash on. this will allow your shutter to fire faster than 1/60 of a second and your blurs and ghosting should disappear. there are other ways, but they'll be explained in a later post after we learn about a few other things.
due to a high risk of beating a dead horse by continuing this little shutter biography, i will end this post here. if you have any questions, feel free to leave'em in the comments and i will reply as quick as i can and try to help you out.
next up: aperture