Wednesday, November 11, 2009
The area of acceptable focus is thin and flat, and unfortunately most of the critters I photograph are curved. The "trick" is to look for a way to lay a thin flat surface over a curve so that as much of it is covered as possible. The fly in the photo I've included with this post has a head that's almost triangle shaped and it should be pretty obvious that you can't shoot it head on. Placing a flat surface against the point of a triangle won't cover much, so there are some angles that just won't work for a single frame no matter how much depth you can get. Even though there are a lot of curves there are still some relatively flat areas that will allow you to make the most of what little depth you have at high magnification. It takes a little experience, but eventually you'll learn to recognize a good angle from a bad one.
The really cool aspect to magic angles is that I have yet to find one that does not work from a compositional standpoint. If I can find a magic angle I'll end up with a well composed photo that has a lot of apparent depth. Since I'm more concerned about composition than getting maximum detail I haven't gotten into focus stacking -just haven't needed to do it yet.
Now for the technique part: For this shot I moved the lens in until the left front edge of the fly was in focus. Then, with the lower left hand corner of the frame locked in place, I moved the upper right corner in until the ridge between the fly's eye and "face" came into focus. I also turned that lower left corner on its axis, kind of spinning the frame so that the upper left corner went deeper into the scene. It's a very minor tilt / twist that makes a huge difference in the amount of the subject that I can cover with the area of acceptable focus.
The result is an image that has a lot of depth simply because I'm not wasting any of it...