Depth of Field
On a regular day where natural light is illuminating a space nicely, (ie, a room in your house or maybe out in the garden in shade) set up your camera on ISO 800. If you are using a zoom lens, set it to 50mm and if you have a choice of lenses, then just use your standard 50mm lens.
Set an object about a meter or so away from you, and then make sure you still have something else going on in the background, like plants in your garden, or a kitchen cabinet, or a doorway, or whatever. Focus your lens on the subject in the foreground. We want to control what happens with depth of field, so in this exercise we’ll set the aperture to F16 and accept the shutter speed reading. If the shutter speed reading is slower than 1/125 second, then use a tripod or lean your camera against something solid to steady yourself. Focus your lens at the subject 1 meter away, then click the shutter.
– is a large number
– is a large depth of field
– is a small hole in the lens
Open your aperture 3 stops to F5.6, and compensate for that change with the shutter speed. (tip: if you open the aperture then that lets in more light, so you will need to use a faster shutter speed by 3 stops). Leave the focus where it is, and take another picture. Remember that it’s like a dance, the aperture and shutter speed always work together, if you do something to one, you have to do something to the other as well.
Then open your aperture 2 more stops to F2.8 and again compensate for that change in the amount of light permitted to the sensor by stopping down 2 stops with the shutter speed. You should be working with a pretty fast shutter speed by now. Take another picture.
– is a small number
– is a small depth of field
– is a big hole in the lens
The last picture shows just some of the plant leaves and flower buds are within the zone of focus, or, depth of field of sharpness. Spot the differences between the three frames if you look at brick wall at the back, the tree branches towards the front and the green leaves right in front of the camera at the bottom left of the frame. In the first photo everything is pretty clearly placed, by the last picture on F2.8, the areas that fall outside the zone of focus become quite fuzzy.
The use of aperture is great for isolating the subject from the foreground and background. It’s lovely for portraits, in fact, I shoot as much as I can in my portrait sessions on F2.8, I want the person focused, or even closer in, like just an eye, or part of a hand, while the rest falls out of focus.
Go on, give it a bash and let me know how you go.