Originally posted by K2 to K50 A number of posters mentioned this "back button" focus: what little research I have done suggests to me that this is only relevant with AF lenses???
For auto focus activation, back button focus is going to work only on AF lenses. But back button focus will give focus
confirmation with manual focus lenses, if you have it pressed while using the lens's focusing ring or while moving the camera/lens unit as a whole while shooting macro. With the shallow depth of field inherent in close focus and macro photography, any help you can give yourself in determining proper focus is good! Find the combination that's going to work for you.
If you're doing single shot work rather than stacking, placement of the focus is crucial. The higher the magnification, the shallower the DOF. Stopping down is only going to help a little. You have to decide for yourself what tradeoff you're willing to make between greater DOF and diffraction softening. This might vary from subject to subject.
With shallw DOF, you can easily have shots where one of your subject's eyes is in focus and the other isn't. My own preference in these situations is to have the nearest eye in focus. Or the nearest bunch of eyes if we're talking insects or spiders!
I also try, as best I can, to position myself so the plane of focus is aligned with the subject to get as much of it as I can in good focus. It's easier to show it.
The eyes are in focus, but the rest of the body, not so much.
By shifting my position, I've gotten the wings, some of the body and legs much clearer.
It's handy if you're shooting subjects that don't freak out when you get this close and move around them. If you're lucky you can even get in close for a portrait: