USE SOFTWARE FOCUS EFFECTS
Deploy the full range of computer-based blur tools for post-shoot control of depth of field
While many depth-of-field techniques can be easily applied in-camera, there are occasions when alterations to the range of sharpness within an image have to be introduced during post-production. There are a surprising number of blurring tools available in software packages such as Photoshop, each providing an effect that approximately simulates the DOF seen in a discrete photographic situation. Credibly introducing blur to an image can vary from being a relatively simple task, to becoming a complex and time-consuming endeavour. This is the key reason for attempting to fully control DOF at the moment of exposure – many of the conditions in which the processes discussed here may be adopted will be when the photographer feels the f-stop-induced blurring in a shot is insufficient and no re-shoot is possible. That being said, in other instances post-production work can produce styles of image that cannot be generated at the camera, such as the popular Brenizer Method described on these pages. This technique has been employed since the days of film, during which time some element of post-shoot work has always been essential for it to work. The reason for the failure of simulated focus effects is the quality of the blending of sharp detail with soft, filtered areas, especially along edges in the scene.
The reason for natural blurring in photographs, via aperture choice, is the varying distance of objects within the frame from the camera position. Where false blurs have to be added, care must be taken to create a realistic boundary between adjacent pixels, where the blur filtration ends, to maintain this illusion of separation. One highly effective solution is to apply blur filters on new layers, then make unfeathered layer masks to produce sharp, highly defined edges to blurred areas. The critical element is to remember that DOF refers to more than just blurring itself. With camera-generated focus being directly related to distance, object size in the composition is inseparably linked – a fact that must be considered when choosing to apply a Photoshop filter.
3 LOCK FOCUS AND EXPOSURE As with shooting linear panoramas, the exposure cannot change between frames if software is to be able to merge them later. Take a reading and enter those settings in manual mode. Focus may also alter, so switch to MF mode once initially focused on the subject.
4 SHOOT, RECOMPOSE, REFOCUS Take your first frame, rotate the camera from right to left, refocus manually if necessary and shoot a frame either side of the subject, which should be kept sharp in all segments. Repeat the process for a row of shots above and below this first row.
5 GROUP FILE SEQUENCE Next open your images in Adobe Bridge or Lightroom and create a Collection of your image sequence, or move them to their own folder, for easy retrieval later. Number your shots by row and segment for reference during the stitching process.
6 STITCH IMAGES Use manual blending methods for better control. Extend the canvas of the top-left segment in Photoshop, drag the other images onto the document and arrange according to position. Use Edit>Auto Align Layers followed by Edit>Auto Blend Layers set to Panorama, to remove seams.
7 CROP AND RETOUCH To fine-tune the final composition, some cropping may be necessary. This will also remove any rough edges created by the stitch. While basic processing may have been done on each segment in RAW, finalise the colour of the wider image now.
BottomWIDE AND SHALLOWthe final stitched composite successfully holds attention on the subject by minimising background detail, while effectively showing the insect in its environment
Below STANDARD COMPOSITIONin this shot the photographer had to choose between a wide frame and greater background detail, or a tighter shot for better blurring