A few days ago a questions was asked of me on Facebook about one of the images I posted. The question asked if I used focus stacking software on the posted image of orchids which were taken while conducting a workshop at Parkside Orchids in Pennsylvania earlier this year. For those of you who don't know, focus stacking software allows you to create a larger depth of field than is normally attainable by merging images taken of the same subject with the same cropping, but with different focus points. When the images are merged the depth of field increases. The image above was the image in question, and no, there was no focus stacking done to this image. Anyone can obtain the same look by understanding the 3 things that effect depth of field, aperture, focus point & focal length.
First, lets look at aperture (or in other words your F-stop), the larger your aperture (F/1.4, F/2.8...) the smaller the depth of field & the smaller the aperture (F/16, F/22...) the larger the depth of field. This image was taken at f/32, which helped maximize my depth of field. Next is focus point, or how close you are to the subject you focused on. Keep this in mind, the closer you get to your focus point the shallower depth of field and images taken at the minimum focus distance of a lens, the DOF will be extremely shallow. This image was taken with the 90mm Macro lens which has a minimum focus distance of about 11 inches. I did not like the composition when shooting that close so I moved away from the flowers to about 22 inches. As I move away from my subject from 11 inches to 22 inches my DOF increased. Lastly, the focal length of the lens also affects your depth of field, the wider the angle of the lens the larger the depth of field. For example a 10mm lens will have a much larger depth of field than a 500mm lens.
In conclusion, to maximize the depth of field of this image, I stopped down the aperture to F/32, moved a little further away from the subject (22 inches) and used a 90mm focal length lens (instead of the 180mm Macro lens which would have had a shallower depth of field).