Often a major goal in macro photography is to obtain a sharp image of the subject, from front to back, with a soft, out-of-focus, non-distracting background. This can be accomplished using a method called focus stacking in which a series of photos are taken with the same camera settings while making slight changes in the focus point for each shot. Various software packages can be used to facilitate the subsequent alignment, stacking and processing required to merge only the areas in focus into a single image.
The Olympus OM-D E-M1 Mark II camera has a shooting mode (Focus Stacking) in which a single shutter activation initiates the capture of 8 sequential images, each focused at a different depth plane, which are then automatically merged into a single JPEG image.
The results of my first attempt to use this feature of the camera are shown here.
The photos were taken at the Butterfly Pavilion in Westminster, CO. The Butterfly Pavilion, opened in July 1995, was the first stand-alone non-profit insect zoo in the U.S. On the first Saturday of each month it is possible to reserve a slot for early admission and tripods can be used for photography.
I was experimenting with the "focus differential" setting, the setting that controls the distance between in-focus areas in the shots. Several of the 8 shots will be quite similar if the setting is too low and there will be blurred regions in the composite image if the setting is too high. I did not hit the ball out of the park in my selections of the setting. With practice I should be able to get better results than what is shown in this post.
Digging deeper into the information available about focus stacking with the Olympus camera, I have learned that the "focus differential" units are in terms of depth of field at the current focal length and aperture. The camera firmware uses information about focal length, subject distance and aperture to compute depth of field and the size of the adjustment in focal distance between shots. Thus, for example, the focal distance difference between shots will be greater at f/16 than at f/2.8.
I have reserved a slot for the early morning entrance to the Butterfly Pavilion on Nov. 3. It is a great place to practice macro photography. If I am feeling really ambitious, I may try using the "Focus Bracketing" mode which allows the photographer to take up to 999 consecutive shots at focus differentials between 1 and 10 in a fast burst.
And I will talk to the personnel at the Pavilion to get help with the identification of the tropical butterflies.