A friend of mine was having some issues with his digital camera, a new DSLR , which means digital single lens reflex, as opposed to a point and shoot. Reflex means you look through the lens when you put the camera up to your eye, allowing you to focus and frame your picture much easier. (There are dual lens cameras, hence the ‘single lens’ designation.)
I’d noticed some camera shake in his pictures so I suggested that he change a few settings in order to help get rid of the shake. Since this person isn’t a techno-weenie like me, he had a hard time figuring out what I meant so I explained it in non-technical terms. If you are new to photography, here’s my explanation:
Think of a room with a single window. The window is equipped with a blind that is able to shut out all of the light, part of it or none of it. The room is the inside of your camera, the window is the lens and the window blind is both the camera shutter, the thing that allows light into the camera in measured portions depending on how long it is open AND the aperture. The aperture is a measurement of how wide the blind is open, not how long it is open.
Three things affect how much light gets into the room. Three things affect how much light gets onto your ‘film’ inside the camera, too. Let’s look at them one by one.
1. The window blind lets light in. You control how much light gets in by opening the blind or closing it. Wide open, lots of light. Halfway open, some light. Closed down, almost no light or no light at all. This is the aperture in your camera.
2. The blind is also the shutter, right? Flinging the blind open for a second, some light will get in. Open it for a longer time and even more light gets into the room.
3. The room, for now, is painted black. This would represent a low ISO. Don’t worry about what ISO is or means, just remember that a low ISO means a black room which would need a lot of light for anyone to be able to see anything in it. Stay with me, this will make sense soon.
Let’s say you are looking for something in the room. When you consider the three things that let light into the room, you will see that you need a combination of two of them to be able to find whatever it is you are looking for.
1. The room is black, there is bright sun outside so you fling open the blind a bit and the object can be found quickly.
2. It’s night time, the moon is out so you open the blind almost all the way and you find the object but it takes some time.
3. It’s a dark night, no moon so you have to open the blind all the way and keep it open until your eyes adjust to whatever light there is. After a long time, you find the object. You think to yourself, ” I should paint this room white so it would be easier to see things on a dark night”.
After painting the room white, which is the same as changing the ISO to a higher number, you run through the same exercises as above. In each example, the blind is open for a much shorter time, even on the dark night. You decide to change the room again, this time by putting mirrors on each wall. This is the same as changing the ISO to an even higher number.
Running through the exercises, you notice that with the mirrors reflecting whatever light hits them, the blind can be opened for a shorter period of time. You’ll notice that the time that the blinds are open is less, also.
These examples should give you an idea of the settings for your digital camera. The aperture can be open or shut or anything in between. The shutter can be open a long time or not very long at all. The ISO can be changed from low and slow to high and fast, just the same as you can paint your room a lighter color to increase the reflection of light, or darker to kill reflections.
Shake comes into the equation now. If the shutter is open for a tiny fraction of a second, there is no risk of shake or blur. If the shutter is open for anything longer than say, 1/125th of a second, there is a great possibility of shake. Keep that shutter open for half a second and you’re begging shake to pop into your pics. What’s the answer?
Look at the examples above. To decrease the time that the shutter is open, we have to adjust the aperture or the ISO. There is a setting for a perfect picture and that setting is a combination of three things. Shutter opening time, aperture width and ISO setting. Each one affects the other.
Fast shutter speed eliminates shake but requires a wider aperture. Once the aperture is open as wide as possible, there is only ISO to play with. After that, you need a tripod and a shutter release to ensure a blur-free photo.
There are two other variables besides the big three. They are ‘noise’ and ‘depth of field’. I will get into these in the next two entries. For now, get used to the big three and see if you can adjust them to eliminate shake. Your camera will have (or should have) three settings other than Auto. One is Aperture Preferred (you tell the camera what aperture you want and it does the rest), Shutter Preferred (you tell the camera the shutter speed you want and it does the rest) or Manual. Manual means that you’re on your own. You decide everything. Good luck with that! You’ll get to be an expert if you practice using these settings.
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