Originally Posted by
rob marshall
Debbie
The DOF on a macro lens is not very high at all, due mostly to the closeness of the subject. DOF is affected by distance from the subject as well as aperture. If you stood on the edge of the Grand Canyon and looked across to the cliffs/rocks across the canyon and shot it on f1/8 it would all be in focus as all objects would essentially be so far away as to be treated as 'infinity' by the camera. If you then swung the camera round, and with the same setting shot a portrait of someone next to you, parts of the person would be out of focus. In my shot I used f/8. I could have used f/22 or even higher, but that degrades the image quality, and you still get some of the subject out of focus due to the closeness of the subject.
It's worth remembering that you only need to use f/16 for landscapes when you have objects that are both near and far from you that you want all to be in focus. If that's not the case, you are better using something like f/8.