Shutter speed is measured in how many fractions of a second, or seconds, the shutter is open for. If the shutter is open for a long period of time, such as 2 seconds (shown as 2″ on a DSLR), light is being taken in for a long period of time, and moving items appear blurred, such as this example image. If the shutter speed is something like 1/1000, then the shutter is open for a short period of time, moving objects will not be blurred. A fast shutter speed is great for sports.Adjusting is simple. Turn your mode dial to ‘S’, and here you should be able to change it to your hearts content. You MUST REMEMBER, however, that the shutter speeds you can change to depend on your ISO setting. This is where it gets complicated. If you can, pick up your camera now, change your shutter speed to something like 10 Seconds (10″) and take a picture of the computer screen, or a lit room. You should just see white. This is because too much light has been brought in. Now, change the speed to something like 1/4000, or as near as you can go, and when you take a picture, you should see just black. This is because not enough light has been brought into the camera. This is when you need to alter your ISO.
Choosing higher ISO values allows faster shutter speeds, and vice versa. You may have to change these settings to get your desired effect. I feel that playing with shutter speed will give you a good sense of how things work. Search, Penki, in the Apple App Store, and you will find a great use for this feature.When taking shots at night, it is vital you know what the ISO is, and when to change it.High ISO’s (1500-3000) are great for night shots. It is complicated, because in the image to the left, while my ISO setting was high, I used a slow shutter speed.For all you absolute beginners, try using a higher ISO for night shots, or shots in the dark, and an ISO of around 300-600 for daytime shots, although you might want to reach 1000.Why ISO works, I do not know, and I still find it hard to get my head round, as you can probably tell, but experimentation is what is needed. Below is a list of different scenario’s, and different ISO values. Take a look.
A flowing river. You want the water to be blurred to show motion. ISO Lo to 200.
A calm bright daytime scene – ISO 200-500.
Splashing water, which you want frozen in mid-air. ISO 500-800.
A still object or building at night – ISO 800-1000
A theatre or classical concert – ISO 1000-2000
A night time scene with much bright lights (like my image above) – ISO 1000 – 2000
Fast moving objects at night. ISO 1500 – ISO hi.Note most cameras may not let you change to certain shutter speeds if your ISO setting is wrong.