Photography knowledge---What is aperture? What is it used for? How to use aperture? Thank you!

The following are answers to similar questions some time ago. I hope they are useful to you.

As far as conventional conditions are concerned, there are roughly the following rules:

The size of the aperture affects the depth of field (other than those at the adjusted focal length, which are within a range before and after the focus point position) The image of the object on the screen is also relatively clear). The larger the aperture, the smaller the depth of field; the smaller the aperture, the larger the depth of field. Therefore, when you want to blur the background (such as a close-up portrait), give priority to using a larger aperture. Otherwise, use a smaller aperture.

The shorter the shutter time (commonly known as the speed), the more it can "freeze" the specific appearance of the object being photographed. For example, it can take 1/1000 of a second to take pictures of splashing water or jumping athletes in mid-air. The dynamics in the video will not be blurred. Using a longer shutter time will record the changes in the object during this period. Of course, misuse of a slower shutter time will result in blurry shots due to hand tremors and moving objects. But you can also intentionally pursue a blurring effect. If you use 1/15 or even 1/4 second to shoot a waterfall or stream, the flow of the water waves will be blurred and it will look very soft.

So, when the depth of field relationship is more important in the photo effect you want, adjust the aperture first. The A position in the camera shooting mode is the automatic function of aperture priority (the size is selected by the photographer).

Furthermore, when the dynamic effect is more important in the photo effect you want, adjust the shutter first. The S mode in the camera shooting mode is the automatic function of shutter priority (the length is selected by the photographer).

I hope the following will be helpful to you

What are the basic rules you need to follow when shooting? What basic knowledge should you keep in mind when shooting? What basic principles are the key to great photography? That’s the following 12 basic photography rules.

⒈Sunshine 16 Rules. This basic rule is suitable for shooting bright, uniformly illuminated scenes during the day, that is, use an aperture of f16 and a shutter speed that is the reciprocal of the sensitivity index. For example, if the aperture is f16, the sensitivity is ISO100, and the shutter speed can be selected as 1/100 second. On this basis, if you are shooting on the beach, you can reduce the aperture to f22, if you encounter cloudy weather, you can enlarge the aperture to f11, and so on.

⒉ Moon 11, 8 and 5.6 rules. This is a unique rule that only works when photographing the moon: when the moon is full, the aperture is f11, and the shutter speed is higher than the reciprocal of the sensitivity index; when the moon is missing, the shutter speed remains unchanged, but the aperture is changed to f8; if only If there is only one crescent moon left, select f5.6 aperture at the same shutter speed.

⒊The law of mechanical shock. The minimum safe shutter speed for handheld camera shooting is the reciprocal of the focal length of the lens used. Below this shutter speed, camera shake may cause the sharpness of the photo to decrease. For example, when using a 50mm lens, the shutter speed should be higher than 1/60 second. If the illumination of the scene is insufficient, you can use a flash, a tripod, or let the camera use some fixed objects to solve the problem.

⒋Gray card rule. During the shooting process, using 18% gray card metering is the best way to obtain a uniformly exposed and accurate photo. It doesn’t matter if you forget to bring the gray card. You can reach out your hand and let it face the light source and use metering Measuring the light with a table or in-camera light meter, just increase the exposure by 1 level based on the metered value (different skin tones may cause a slight deviation in the metering accuracy).

⒌The law of depth of field. When focusing on a distant subject, the length of the depth of field area in front of the subject is usually twice as long as the length behind the subject. In other words, the subject is usually in the last third of the depth of field. This is the same at all apertures and focal lengths, except that the smaller the aperture and the shorter the focal length, the greater the depth of field and the greater the length of sharpness you can capture.

⒍Maximum digital printing rule. In order to calculate the maximum print size of the photos that your digital camera can output (based on acceptable imaging quality), you can divide the maximum resolution of your camera by 200 to calculate the print size of this digital camera. Specifications (some photography articles and photography books refer to them as exhibition-level photo quality), if divided by 250, it is the ultimate printing specification of the machine, and the unit of the result is inches.

⒎Exposure rule. The most classic explanation is: "Expose according to the highlights, and then print according to the dark parts." This is equally accurate for traditional reversal films and digital cameras, but when using negative films - especially color negative films, it is best to Overexposed by one stop.

⒏Fast flash exposure rule. When using an automatic flash that does not automatically reduce the flash output to achieve flash fill light, you can increase the sensitivity setting on the flash to 2 times the sensitivity of the focal length you are using.

⒐Flash working range rule. This rule is all you need to know the maximum operating range of your flash. The rule is: "Double the distance, 4x the sensitivity speed." For example, if the sensitivity is ISO100, the maximum effective distance of the flash is 6 meters, then when you replace the ISO400 film or increase the sensitivity of the digital camera to ISO400, the maximum effective distance of the flash is 12 meters.

⒑Megapixel multiplier rule.

In order to double the resolution of a digital camera, you have to multiply the number of effective pixels of the digital camera by 4 to do it (not 2x!). Why is that? If you want to double the resolution, you must double the effective pixels of the image sensor in both the horizontal and vertical directions. Therefore, the number of pixels on the image sensor is naturally 2 times × 2 times = 4 times!

⒒The law of solidification of moving bodies. In order to record an object moving perpendicular to the optical axis of the lens, you need to increase the shutter speed by 2 stops when the object is moving toward or away from the camera; when the object is facing or facing away from the camera at an angle of 45 degrees, When moving toward the camera, the required shutter speed is the shutter speed required when the object is moving toward or away from the camera, plus 1 stop. For example, if a person is running towards you at a medium speed, it takes 1/125 second to freeze the movement. When he runs sideways through the viewfinder at the same speed, a shutter speed of 1/500 second is needed. If he Therefore, when running diagonally, only 1/250 second shutter speed is required.

⒓The sunset rule. In order to obtain accurate exposure when shooting at sunset, the metering area should be above the sun, but not include the sun itself. If you want the entire scene to look like it was half an hour after sunset, you can reduce the aperture by 1 stop or Reduce the exposure by one level.