Aperture, Speed and Sensitivity —— Photography Basis (6)

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Fundamentals of Thematic Photography (6)

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Continue yesterday's topic and share some basic knowledge of photography.

Just after listening to Mr. Dai's class, I may not understand and digest thoroughly or have not taken practical photos, so I have no deeper experience or feeling. But whether it can be written clearly or not, it is an attitude to record it first, then sort it out and summarize it slowly, and then correct it after perfecting or supplementing or sharing the wrong places.

It may also bring some gains to friends who haven't started shooting with SLR cameras, because yesterday a friend specially wrote to me privately and collected all the basic photography contents I shared. This may be the value of writing it down.

The following content involves the technical parameters of shooting, which may be super boring, but it is the most basic shooting technology. After mastering the proportion of various parameters, it determines the quality of a photo. Have you found that all the good photos that have won or not won prizes but have been confirmed by word of mouth are lined with a set of technical parameters, which determines how such good photos are taken? Well, before it's too late, let's start sharing today.

1, first briefly explain the imaging principle of SLR camera.

According to the picture below, we can see that the light enters the camera through the lens, bounces back to the Wuling mirror through the mirror in the camera, and reflects to the photographer's eyes in the Wuling mirror according to the position of the arrow. After the photographer sees the image, he presses the shutter and becomes a photo. If you don't understand this imaging principle, simply put, the light enters your sight through the lens, and then you can get a photo by pressing the shutter.

As can be seen from this picture, the amount of light entering is related to the aperture size, which is what was said yesterday: the larger the aperture, the more light entering and the more photos exposed. For example, the brightness of the photos taken is good, which means that the exposure is just right, that is, the aperture is just right; If the photo is dark, it means that the exposure is not enough, that is, the aperture is too small and the light is not fully reflected on the photo; If the photo is white, it means too much exposure, too large aperture, too much light, and the photo is too white.

2. Similarly, the light quality of photos is limited by three factors: aperture, speed and sensitivity.

? Aperture: It is the aperture size for receiving light. The larger the aperture, the more light.

? Commonly used aperture are:

? F2.8、F4、F5.6、F8、F 1 1、F 16、F22、F32

? The larger the aperture, the more exposure.

Speed: the shooting time, that is, the speed of the shooting process. For example, it may take about 3 hours to take a photo in M mode when shooting the trajectory of a star. Of course, after the speed is too slow, people's hands may tremble. Especially slow speed shooting needs the help of a tripod and a remote control that presses the shutter. Generally, the speed of hand-held shooting is1/60s, so that the photos won't be blurred.

Commonly used speeds are:

? 30、 15、8、4、2、 1、 1/2、 1/4、 1/8、 1/ 15、 1/30、 1/60、 1/ 125、 1/250、 1/500、 1/ 1000、 1/2000、 1/4000、 1/8000

? The higher the denominator, the faster the speed.

Sensitivity: the degree to which a camera or photographer feels the light in the scene when shooting indoors. Generally, ISO is set to 3200, which can meet the requirements.

? Commonly used ISO (taking Canon 6D as an example):

? 100、200、400、800、 1600、3200、6400、 12800、25600

? With other parameters unchanged, the larger the number, the more exposure.

3. Matching of aperture and speed.

? As shown in the figure below, a simple understanding of exposure combination is to use different exposure combinations to obtain the same exposure. This is the approximate ratio, and the exposure can also be understood from the size of the middle hole of the diaphragm blade.

Let's call it a day. Food has been provided. Two young ladies will have dinner together. We will continue tomorrow.