We had a class at our church that taught us about emergency preparedness. It was getting dark outside, and my D3100 wanted to set a much longer shutter speed than I wanted. I decided to switch to manual mode to get the settings the way I wanted them. Even in Manual mode, its amazing to see the difference between the two shots below:

There’s no difference in the ISO, shutter speed, or aperture. These pictures were taken within a second of each other. So what made the drastic difference?

I had my D3100′s White Balance set to Auto. In the interval between these shots it resampled what white “should” be, and corrected, resulting in the change. I realized this, and set it to Manual so my pictures would all turn out the same.

Auto mode is meant to crank out good pictures, without the person pushing the shutter having to think. It works well most of the time, but it can never know what you truly want. If you want an ultra-high shutter speed to capture a breaking lightbulb, it doesn’t know that- your camera will set a speed between 1/125 and 1/15 and take a picture of the blurred bulb. If you want to take a silky picture of a waterfall, you camera doesn’t know that- it’ll use that same 1/15 shutter speed and create a boring picture of frozen-looking water.

The big advantage of DSLR’s is that they let you have complete control of the picture you take. You can do anything you want. Knowing what you want becomes the biggest issue.

Experiment! The more you goof with your camera’s settings, the more you’ll know what you want.