What light does documentary photography use?

In normal weather, 200 degrees is enough.

The weather is particularly sunny, 100 degrees.

400 degrees in rainy days

Selection of shooting skill sensitivity

Portraits, landscapes, still lives, etc.

Generally speaking, this kind of theme requires beautiful pictures and rich details, and better results can be achieved by using the lowest sensitivity or the default sensitivity of the camera. Of course, everything is not absolute. Some photographers need to create the effect of Gao Fancha and high grain, which can be enhanced by increasing the sensitivity appropriately.

Sports or documentary photography

The most important thing about this kind of photos is that they can truly record the most wonderful moments. In many cases, higher shutter speed is required or flashing is not allowed. If there is enough light in the scene, the sensitivity should naturally be set lower, so as to effectively ensure the image quality. If the light at the scene is dark, it is necessary to appropriately improve the sensitivity, first ensure that you can take pictures, and then consider the picture quality.

Weak light photography

Many friends often ask me, what sensitivity should I use to take pictures at night? This problem can't be generalized, it depends on the specific shooting subject and shooting requirements. If you put your camera on a tripod and shoot night scenes or urban buildings at night, you should use the lowest sensitivity or the default sensitivity setting of the camera, so that you can get a delicate and uncluttered picture. If you shoot people in the dim light of the bar at night, you have to improve the sensitivity and use a slightly higher shutter to solidify the protagonist.

Anyone who has used traditional cameras knows that the most important index of film is sensitivity. Although digital cameras don't use film, CCD(CMOS) used for light sensing also has corresponding requirements for exposure. So CCD(CMOS) is also equivalent to film, and has a certain sensitivity. For the convenience of digital camera users, digital camera manufacturers equivalently convert the CCD(CMOS) sensitivity of digital cameras into the sensitivity of traditional films, so digital cameras have the concept of "equivalent sensitivity".

According to the traditional classification of measuring film sensitivity, at present, the "sensitivity codes" of digital cameras are distributed in the middle and high speed range, with the lowest being ISO50 and the highest being ISO6400, most of which are around ISO 100. This type of digital camera has a single sensitivity, and its CCD(CMOS) sensitivity tolerance is very small, so it is harsh on shooting conditions, and the use effect will be poor under the condition of too strong or too weak light. In addition, the "equivalent sensitivity" of some digital cameras can be selected within a certain range, but the shooting effect of high sensitivity and low sensitivity is different. If you don't know the "equivalent sensitivity" of a digital camera, you'd better adjust it to the default sensitivity or the lowest sensitivity when shooting.

Carefully consider the setting of sensitivity before shooting. If the CCD(CMOS) sensitivity of a digital camera is low and the ambient light is slightly dim, the camera will have to use a flash, which will darken the background. Higher sensitivity will give you great flexibility. For example, the natural balance between the foreground and the background can be achieved without the need for a flash in the room. Shooting high-speed sports requires high sensitivity to get better results.

So, is the higher the sensitivity, the better the shooting effect? At present, the sensing method is to improve the sensitivity by amplifying the current signal. This processing method will amplify the useful signal and noise signal at the same time. The noise ripple of the image is coarse and some details are lost, which affects the image quality. At present, the default sensitivity of most digital cameras is generally around ISO 100, and a few products are ISO50.

The meaning of sensitivity ISO

In traditional film cameras, ISO stands for the standard of photosensitive speed; In digital cameras, the definition of ISO is the same as that of film, representing the photosensitive speed of CCD or CMOS photosensitive elements. The higher the ISO value, the stronger the photosensitivity of photosensitive materials. The calculation formula of ISO is S=0.8/H(S sensitivity, h is exposure). As can be seen from the formula, the higher the sensitivity, the lower the requirements for exposure. The exposure speed of ISO 200 film is twice that of ISO 100. That is to say, under the same conditions, the exposure time of ISO 200 film is half that of ISO 100 film. In digital cameras, the number of light sources and the value of picture brightness can be changed by adjusting the equivalent sensitivity. Therefore, the sensitivity has also become a value that indirectly controls the brightness of the picture.

In the traditional 135 film camera, the equivalent photosensitive value is a measure of the sensitivity of the camera film to light, which is usually expressed by ISO number. The larger the number, the stronger the optical rotation. Commonly used expressions are ISO 100, 400, 1000, etc. Generally speaking, the higher the sensitivity, the thicker the film particles and the worse the magnification effect.

The traditional camera itself has no sensitivity, because sensitivity is only a quantitative sign of the sensitivity of photosensitive materials to radiation energy under certain exposure, development and testing conditions. Anyone who has used a traditional camera knows that the most important index of film is sensitivity-in layman's terms, it is to measure how much light is needed to complete accurate exposure of film. We bought100,200,400 films in the camera shop, and the numbers represent the sensitivity. Sensitivity is generally expressed by ISO value. With the increase of this value, the sensitivity of the film to light increases, so that it can be shot in different light. Movies like ISO 100 are most suitable for outdoor shooting on sunny days, while ISO400 movies can be shot indoors or in places with poor light, such as early morning and dusk.

However, because the camera is different from ordinary cameras, its photosensitive device adopts CCD or CMOS, so there are corresponding requirements for exposure, and there are also problems of high and low photosensitive sensitivity. This is equivalent to a certain sensitivity of the film. In order to facilitate the understanding of digital camera users, digital camera manufacturers generally convert the sensitivity of digital camera CCD (or light sensitivity) into the sensitivity of traditional film, so digital cameras have the saying of "considerable sensitivity".

From the point of view of measuring film sensitivity, at present, the sensitivity of digital cameras is distributed in the middle and high speed range, the lowest is ISO50, the highest is ISO6400, and most of them are around ISO 100. For some digital cameras, the sensitivity is single, and the sensitivity tolerance of CCD is very small, which limits their use effect in the case of too strong or too weak light. Other digital cameras have a certain sensitivity range, but even within the allowable range, the shooting effect is different if the sensitivity is set high or low, so we should put the best sensitivity in normal shooting. Like traditional cameras, low ISO values are suitable for creating clear and soft pictures, while high ISO values can compensate for poor lighting environment.

When the light is insufficient, the use of flash is inevitable. However, in some cases, such as exhibition halls or performances, if it is not allowed or convenient to use flash, the brightness of photos can be increased by ISO value. Because of the adjustability of ISO value of digital camera, sometimes we can only reduce the use times of flash by increasing ISO value and increasing exposure compensation. Increasing the ISO value can increase the brightness, but it may also increase the noise of the photo.