Understanding Selective Focus
Selective focus is an editing technique that can be used to make specific objects stand out in a photograph. Without selective focus, this task can be tricky, but the selective focus technique makes it very easy. This is a standard technique for professional photographers. It will keep the selected object sharp and in focus, while the rest of the shot will have blurred edges and appear to be out of focus.
How to Achieve Selective Focus
There are several different ways in which this selective focus can be achieved. Find an element in the photo that can be used to be strongly out of focus. A telephoto lens is best, as the telephoto will bring the object into focus and everything else out of focus. A wide aperture size, or f stop, can help achieve this technique. A large aperture size and fast shutter speed will ensure that as much light as possible gets into the film. Angling to the subject can take some practice, but is an excellent way to achieve this effect. Choose a shooting angle so that the foreground and background of the shot are further apart. This makes the background be very out of focus.
Depth of Focus
Ultimately, selective focus is how the depth of field and brightness is used. If you are having difficulties achieving this with the camera, then digital photo editing software can create the same effect by working with the depth of field and the contrast. Most advanced editing programs will have an internal camera that can be used to change the depth of field. In fact, most programs will have a depth of field tool.
There are several digital techniques that can be used to achieve this effect. Focus stacking will combine several images that were taken at different focus distances. This provides a much greater depth of field than an individual photo. Wavefront coding can be used to create optical transfer functions that produce point spread functions for the images and light. These are needed to alter the distance and depth of field in a photo. A plenoptic camera will capture 4D light. This 4d light changes the distance and can be used to create selective focus.
Selective focus is frequently used with nature photographs. These photos are challenging because of the narrow depth of field, and yet to achieve selective focus, the depth of field must be large. Digital cameras makes it easy to see if the chosen shooting options create a selective focus shot or if something should be changed. When taking a close up photo, even a small change can make a very large difference. Try experimenting with your camera until you find the best settings to achieve this effect. Each camera will be different.
It is really the lenses that are important. Several SLR lenses have been created specifically for selective focus shots. These lenses will have flexible barrels so that it can be bent, pulled or pushed to create the dynamic image over the very narrow focus plane. This is much faster than creating the same type of image using Photoshop.