Depth of field, put simply, is how much of the picture is in focus. You might want to shoot a photo which is sharp from the foreground to the horizon ( commonly called a long or deep depth of field), or one where the main subject is in focus and the rest of the image is blurry (a short or shallow depth of field) We are going to start by looking at ways we can change that. The first way is by changing the aperture.
A subject of your choosing. Find something between 50-100 cm across, like a vase with flowers, or some fruit, or a statuette.
A camera with adjustable aperture; all DSLRs, Mirrorless and Bridge cameras have this. Some advanced compacts do too.
Set your camera into Aperture Priority (A or Av mode) if you have it and put ISO on Auto. (If you are stuck, message me with your camera model, and I shall tell you how.)
When you rotate the adjustment wheel of your camera, the aperture size will change. You should see this change on the cameras display, you might not see it in the lens.
The display will show a number preceded by the letter f. You might not be able to see it, but this will adjust the aperture of an iris inside your camera’s lens. A wide aperture will have a low number like f/1.8 or f/3.5. A narrow aperture has a high number, e.g. f/18 or f/22. The lowest and highest number will depend on your lens.
Stand about a metre from your chosen subject. Carefully squeeze the shutter button. Shoot one photograph at the widest aperture (smallest f/ number) and one at the narrowest . Compare the two shots. The one taken with a wide aperture should have a more blurred background that the one with the narrowest aperture.
More about depth of field next time.
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