What is the most suitable film sensitivity when shooting outdoor scenery?

In normal weather, 200 degrees is enough

On particularly sunny days, 100 degrees

400 degrees on cloudy or rainy days

Photography tips The choice of sensitivity

Portraits, landscapes, still lifes, etc.

Generally speaking, these types of subjects require delicate images and rich details. Using the lowest sensitivity or the camera's default sensitivity can achieve better results. Good results. Of course, there are no absolutes in everything. Some photographers need to create high-contrast, high-grain effects. Appropriately increasing the sensitivity can enhance this effect.

Sports or documentary photography

The most important thing about this kind of photos is that they must be able to truly record the most exciting moments. In many situations, a higher shutter speed is required or the use of flash is not allowed. If the scene environment is well lit, then naturally the sensitivity should be set lower to effectively ensure image quality. If the light at the scene is relatively dim, you should increase the sensitivity appropriately. First, ensure that you can take a photo, and secondly, consider the quality of the picture.

Low light photography

Many friends often ask me, what sensitivity should I use when taking photos at night? This issue cannot be generalized and should depend on the specific shooting subject matter and shooting requirements. If you set the camera on a tripod to shoot night scenery or city buildings at night, you should use the lowest sensitivity or the camera's default sensitivity setting to get a detailed picture without noise. If you are photographing people in a dimly lit bar at dusk, you have to increase your sensitivity and use a slightly higher shutter speed to freeze the subject.

Anyone who has used a traditional camera knows that the most important indicator of film is sensitivity. Although digital cameras do not use film, the CCD (CMOS) used to sense light also has corresponding requirements for exposure. Therefore, CCD (CMOS) also uses the equivalent of film and has a certain sensitivity. In order to facilitate digital camera users, digital camera manufacturers convert the sensitivity of the digital camera's CCD (CMOS) to light into the sensitivity value of traditional film. Therefore, digital cameras have the concept of "equivalent sensitivity".

Using the traditional classification of measuring film sensitivity, the current "sensitivity codes" of digital cameras are distributed in the medium and high speed ranges, with the lowest being ISO50, the highest being ISO6400, and most of them around ISO100. . The sensitivity of a certain model of digital camera is single, and its CCD (CMOS) sensitivity latitude is very small, so the shooting conditions are relatively harsh. When the light is too strong or weak, the use effect will be very poor. In addition, the "equivalent sensitivity" of some digital cameras can be selected within a certain range, but there are some differences between the shooting effects of high sensitivity settings and low settings. If you don't understand the "equivalent sensitivity" of digital cameras, , it is best to set it to the camera's default sensitivity or the lowest sensitivity when shooting.

We should carefully consider the sensitivity setting before shooting. If the digital camera CCD (CMOS) has a low sensitivity and the ambient light is slightly dark, the camera will have to activate the flash, and the use of flash will make the background dark. A higher sensitivity will give you great flexibility. For example, you can shoot indoors without a flash and achieve a naturally balanced shooting effect of the front and rear scenery. When shooting high-speed sports, a high sensitivity can produce better results. .

So, does the higher the sensitivity, the better the shooting effect? The current method is to increase the sensitivity by amplifying the current signal. This processing method will not only amplify the useful signal, but also amplify the noise signal. The image noise ripples are rougher and some details are lost, affecting the image quality. At present, the default sensitivity of most digital cameras is generally around ISO100, and a few products are ISO50.

The meaning of sensitivity ISO

In traditional film cameras, ISO represents the standard of light-sensitive speed. In digital cameras, the definition of ISO is the same as that of film, and it represents the sensitivity of CCD or CMOS photosensitive elements. Speed, the higher the ISO value, the stronger the photosensitive ability of the photosensitive material. The calculation formula for ISO is S=0.8/H (S sensitivity, H is exposure). From the formula we can see that the higher the sensitivity, the less exposure is required. The speed of ISO 200 film is twice that of ISO 100 film. In other words, under the same conditions, the exposure time required for ISO 200 film is half that of ISO 100 film. In a digital camera, by adjusting the equivalent sensitivity, the amount of light source and the brightness of the picture can be changed. Therefore, sensitivity has also become a value that indirectly controls the brightness of the picture.

In traditional 135 film cameras, the equivalent sensitivity value is a measurement of the sensitivity of the camera film to light. It is usually expressed in ISO numbers. The larger the number, the stronger the sensitivity. Commonly used expression methods There are ISO 100, 400, 1000, etc. Generally speaking, the higher the sensitivity, the coarser the grain of the film, and the worse the effect after enlargement. Digital cameras also use this ISO value to indicate the exposure used by the metering system. The lower the base ISO, the higher the required exposure.

Traditional cameras themselves have no sensitivity at all, because sensitivity is only a quantitative indicator 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 indicator of film is sensitivity—in layman’s terms, it is a value that measures how much light a film needs to achieve an accurate exposure. The numbers on the 100, 200, and 400 films we buy in camera stores represent the sensitivity. Sensitivity is generally expressed by the ISO value. As this value increases, the film's sensitivity to light also increases, so that you can shoot in different lights. Films like ISO100 are most suitable for shooting outdoors in bright sunshine, while films with ISO400 can be used indoors or in low-light environments such as early morning and dusk.

However, because a camera is different from an ordinary camera in that its photosensitive device uses CCD or CMOS, there are corresponding requirements for exposure, and there is also the issue of photosensitivity. This is equivalent to the fact that film has a certain sensitivity. In order to facilitate the understanding of digital camera users, digital camera manufacturers generally convert the CCD sensitivity (or sensitivity to light) of digital cameras into the sensitivity value of traditional film. , so digital cameras also have the term "considerable sensitivity".

Using the usual method of measuring film sensitivity, current digital camera sensitivities are distributed in the medium and high-speed ranges, with the lowest being ISO50, the highest being ISO6400, and most of them around ISO100. For some digital cameras, the sensitivity is single, and the sensitivity latitude of the CCD is very small, which limits their use in conditions where the light is too strong or too weak. In addition, some digital cameras have a certain range of sensitivity, but even within the allowed range, the shooting effect will be different if the sensitivity is set to high or low. Normally, the camera should be placed at the optimal sensitivity for shooting. File on. Like traditional cameras, low ISO values ??are suitable for creating clear, soft pictures, while high ISO values ??can compensate for insufficient lighting conditions.

When the light is insufficient, the use of flash is inevitable. However, in some situations, such as exhibition halls or performances, where the use of flash is not allowed or inconvenient, the ISO value can be used to increase the brightness of the photo. The adjustability of the ISO value of digital cameras allows us to sometimes reduce the number of flash uses only by raising the ISO value, increasing exposure compensation, etc. Raising the ISO value can increase the brightness, but it may also increase the noise in the photo.