Different chemical reactions are used in combinations during chemical synthesis in order to obtain a desired product. In biochemistry, a consecutive series of chemical reactions (where the product of one reaction is the reactant of the next reaction) form metabolic pathways.
AF-S is AF 'single'- your camera will focus on a fixed object when you press the AF button and will remain focused on that point for as long as you hold the button down.This is best for static subjects.AF-C is AF 'continuous' - the camera will focus on whatever is in the relevant AF points (depending on how you have your AF coverage set up) and will attempt to keep the subject in focus wherever it moves, whether that's towards/away from the camera or laterally.F-A is AF 'auto' and automatically switches between the two AF modes depending on what the subject is doing. This requires less effort on the part of the photographer, but you are relying on the camera guessing correctly what you are focussing on, and may result in unexpected focus.
1 A number of new lenses such as the Nikon 800mm f/5.6E VR now feature fluorite elements. 2  G â If you see a letter âGâ after aperture in the lens, for example âNikon 50mm AF-S f/1.4Gâ, it means that the lens does not have an aperture ring like the old lenses. AF â stands for Auto Focus, which means that the lens can automatically focus through the camera. 2  AF-D â Auto Focus with Distance information. 3  Same as AF, except it can report the distance between the subject and the lens and then reports that information to the camera.