When a friend of mine got a new camera and asked for some pointers, I shared the same projects that were assigned by Tom Turner in my very first black and white photography class back in the early ‘90s. These projects are good exercises to help beginning students better understand the "Exposure Triangle" of Aperture, Shutter Speed, and ISO. All of these can be performed using Aperture Priority Mode.
1. Minimum Depth of Field. With a wide open aperture setting (~f2.8 or similar), isolate a single subject by blurring out the background/foreground and just leaving the object sharp. Getting close to the subject with a telephoto lens helps. With a wide open aperture you'll have plenty of light and probably won't need a tripod. This image was made while laying on the grass at Point Reyes with a 105mm macro lens, intentionally looking through some foreground iris flowers to emphasize a California Poppy on a windy, hazy day.
2. Maximum Depth of Field. Select a small aperture, f16, and a scene with both near and far subjects that you want to keep in focus. You will find this technique easier with a wide angle lens. A smaller aperture means less light coming through the lens, so you'll have a longer exposure time. A tripod is a good idea, especially in low light. This image of a gnarled bonsai tree in Zion National Park was made with a 70-200mm telephoto lens at f22. I found a location where I could frame the tree in the huge background arch which was about half a mile away. To keep both sharp I used Live View on my Nikon D800E and zoomed in until I could see both tree and background up close, then manually focused to a point where I could keep both sharp.
3. Stopping Action. Find a fast moving object in motion, like a running dog, surfer, jumping skate boarder, etc, and use a fast shutter speed to stop the action. Select a wide open aperture (~f2.8) and fast ISO, 800 or 1600 to freeze the subject at the peak of action. You'll want at least 1/500th of a second if you can get it. Its easier with lots of light. The image here shows Rob McKay jumping across an exposed gap in the ridge while we were climbing the Evolution Traverse in the High Sierra this past summer.
4. Showing Motion. Find a moving subject but this time use a slow shutter speed to blur the image, showing motion. Use a small aperture (~f16) and low ISO, (100) and pan the camera as the subject moves, or use a tripod and let the subject blur through the scene. The slower the subject moves, the longer the shutter speed you will need. Try it in low light for easiest results. For a panning shot of a runner or biker, try using 1/10th of a second. To show moving water in a waterfall use ~1 second exposure or more. The hard part is getting enough of the subject sharp to make a good image.
For advanced users: You can pop the flash to help get the sharp image as well as the blur. Here’s what I did on this image of Brad Parker mountain biking last spring while shooting a new pack for MindShift Gear: Set the flash settings to "Rear" sync. This will let you use a slow shutter speed and the flash will fire at the end of the exposure. If you use "Slow" sync, it will fire at the beginning of the exposure and the effect is bizarre as it looks like the person is jumping out of their body. After the exposure, look at the image on the LCD. If the flash is overpowering the ambient light, turning down the flash exposure compensation. With my SB900 Nikon Speedlight, a setting of -2.3 seems about right.
I hope you find these lessons helpful. We go much more in-depth on these techniques in our photo workshops.