image on the left: 1/640SEC, f/5.6, ISO 100
Note: 1/200 = faster than 1/30
The faster it closes, the less light it will allow in, so it’ll create a darker image, AND the more in-focus the image will be (free hand).
If you slow it down, more light has potential to flood the sensor, AND the blurrier the image will be (free hand). A slower shutter is how you get that smooth water effect in landscape images, or the streak of light on the freeway (with a tripod). It’s also how I get my artistic blurry images (free hand).
On a very bright day, raise the shutter (make it fast), to reduce the amount of light
At night or in lower light-situations, lower it (slow it down) to increase the amount of light into the sensor