Focus Stacking: Extending depth of field in close-up photography

When taking close-up photographs, or indeed any photographs, there is a delicate balance of factors that allow us to limit or to maximise the parts of an image that are in focus; Aperture, Lens focal length and Subject distance. The choice then depends on what you are trying to show do you go for a larger working distance with a telephoto lens versus smaller working distance with a wide angle lens to gain the detail and depth of field you need. Then how far do you stop down your aperture? If you use smaller apertures that may not be getting the best out of your lens. This is where digital techniques to extend depth of field come into use with focus stacking.