What are the aperture priority shooting techniques of the hood? What should I pay attention to?

　　What are the shooting techniques of the aperture priority of the hood? This is a "hot topic". Most people use it to shoot most of the occasions, but they don't necessarily master them well.

　　1. Choose the aperture size from the depth of field. The biggest function of the iris is to control the amount of light, just like the caliber of the faucet controls the amount of water. But the law of optical imaging tells us that the size of the aperture directly brings about the difference in the depth of field of the picture.

　　Yes, the photo we took is essentially a flat surface, but in terms of the world of the picture reflected, the picture actually has a thickness, and this thickness is the depth of field.

　　For example, our picture is actually a box-shaped body. The one facing us is one side, and there are five other sides; if the side line facing us is called length and width, the depth of field is actually It is the "height" of the cabinet, and the size of the "height" is the size of the depth of field.

　　When we design the picture composition, we always have to consider the depth of field of the picture. We rely on the size of the aperture to design the depth of field, large aperture and small depth of field, small aperture and large depth of field, we can design the composition according to this rule.

　　2. Choose a medium aperture in consideration of image quality. The aperture range of a general lens is between 2.8-18, and different lenses have different ranges. Some are larger than 2.8, such as 1.8, 1.4, etc., and some are smaller than 18. Our Chinese culture pays more attention to "the golden mean", that is, don't go to extremes, don't use the aperture size to the extreme in ordinary shooting; in terms of image quality, the general lens has the best between 5.6-11 effect.

　　Generally, choose a smaller aperture when shooting large scenery, large scenes and night scenes, and choose a large aperture when shooting a few people or single portraits. Many people like to use a large aperture to blur the background to shoot portraits. If the maximum aperture of the lens is 1.8, he will use 1.8 to shoot. In fact, this is not the case. Although the maximum aperture of this lens reaches 1.8, when shooting with a 1.8 aperture, The effect is often not the best, the best is at the aperture one or two stops smaller than 1.8, so here is a reminder, do not "abuse" the large and small apertures.

　　3. The overall control learns to "concession". The advantage of aperture priority is self-evident, but sometimes "Although the wine is good, don't be greedy." For example, when shooting night scenes, according to your imagination, use an aperture of 18 to shoot in order to achieve a large depth of field. It is said that it can also shoot the starry effect of lights, and set a relatively ideal sensitivity such as 200-400. However, while shooting, as the darkness intensifies, the speed display bar keeps flashing, which means that under the aperture and sensitivity parameters you set, the shooting time is far more than 30 seconds, and the camera is at least here. Cannot complete shooting in this mode. At this time, someone has to stand up to mediate, adjust a certain parameter, and "take the overall situation into consideration" once. Who will make concessions? If you want to make concessions in sensitivity, the picture noise will increase and the image quality will be greatly reduced. Who will make concessions? Only the aperture concession is to increase the aperture appropriately to solve the problem.