One of my Facebook friends asked about manual focus, which is a good subject that we need to talk about. Some photographers like to use auto focus when shooting, but in the macro world it’s not a good options in some cases. When setting up a macro image and working with very shallow depth afield which happens when we choose a smaller f/stop number, we will have small area of the image in focus, and large areas that will be out of focus. We have to decide what part of the image we want to be in focus, and make sure we get that area in focus by manually focusing our lens on that particular area.
With this Dragonfly image, I’m using a small number f/stop of 3.5, which will give me very little in focus. Shooting at f/3.5 I may only have a tiny quarter of an inch in focus, and the tiny bit of focus needs to be on the head of the dragonfly. If I choose auto focus, it can’t read my mind that I want to pinpoint the head of the dragonfly for my focus, so we need to manually focus our lens till we see the head of the dragonfly in focus.
Same with this image of flowers in the dew drops, I’m using a small f/stop number of 2.8 giving me very little in focus. I need pinpoint accuracy of my focus if I want it on the tiny flower inside the dewdrops, and I can’t rely on my auto focus to get me there. I want those flowers in the dewdrops to be the only thing sharp in the images, and the rest of the subjects just a soft blur. I need to manual focus till I see those flower inside the water drops come into nice sharp focus.