Anomalies and (some) Fixes

As I experimented with capture and processing of images for focus stacking, I discovered some recurring anomalies that I had never heard about in any presentation or article that describe the technique.  This is most disappointing if you rely on reviews and articles for product information, in addition to the advertisements, when making a purchase decision.

When capturing the images for a focus stacking operation, the focus point of the lens is set on various parts of the subject.  This can be done in one of two ways; by adjusting the focus distance while keeping the camera position fixed, or by adjusting the camera position while keeping the focus distance fixed.  One image presented three anomalies all related to the varying image magnification as a result of changing the focus distance.  The focus slices taken of the orchid image below were accomplished by changing the focus distance with the camera in a fixed position on a tripod. [Read more…]