Tips on using sensitivity

Introduction: What is brightness? Why do you have to adjust the brightness according to the light at the scene every time before taking a photo? In fact, ISO brightness, aperture, and shutter can be said to be determined during shooting One of the three major elements of bright exposure. For all photographers, images come from the refraction of light. Only through light can the value of the picture be conveyed. Therefore, this article will start with the basics to understand the use of ISO sensitivity, and then explain it through practical examples, so that you can easily learn and shoot. Tips for using sensitivity

Let’s start with ISO characteristics

ISO is the brightness that everyone often talks about. It is an important basis for judging the required values ????of aperture and shutter. The exposure values ??form a triangular relationship, allowing the amount of light to be balanced with each other, thereby achieving set standards and good shooting results. For each photo during operation, the ISO value will directly affect the shutter speed and aperture adjustment. As the ISO value is higher, the exposure time will be shortened. For example, if the correct exposure value required by the reader when shooting in the afternoon is ISO 100, aperture F5.6, and shutter speed 1/30 second, if the player adjusts the ISO to 200, because the aperture remains unchanged, the required exposure The time will be shortened by 2 times, from 1/30 to 1/60 second. The imaging will find its balance point with a shorter exposure time and a reduction of half the amount of light. ISO will not have any impact on the aperture.

Simply put, the higher the ISO value, the faster the shutter speed can be provided under the same light source environment, which can effectively avoid the occurrence of hand shake, such as in the woods, basements, and late-night alleys. There is a new solution for shooting in relatively harsh environments.

Low ISO long-term exposure can keep the image quality clear and sharp (ISO 100).

The picture above is a 100% crop of the original picture.

High ISO will produce more noise

However, as the ISO brightness increases, the image details will also change to varying degrees. Under high sensitivity, the image will be different due to the acquisition of light. Due to objective factors such as environment, high sensitivity enhancement is also accompanied by gradually increasing noise, especially in dark areas and shadows. Therefore, if players have the need to shoot large-size and pure images, it is recommended to conduct more tests, and even use low-sensitivity brightness as much as possible to achieve a balance between image quality and capture, in exchange for clearer and sharper images.

If the shooting time allows, it is recommended to use a tripod to assist, so that the image quality can be more perfect. Of course, for some players, what noise represents is not entirely a bad thing. In the era of traditional film, this kind of thing called graininess was sometimes considered to be the main element of film FU.

The ISO value of some mid-to-high-end models can be set in 1/3 step increments.

Although automatic ISO is very convenient for the general public, misjudgments sometimes occur and players should not be careful.

However, in digital images, the problem caused by high sensitivity is not only noise, but also reducing the sharpness and contrast of the image, making the image feel more flat, and even making it feel like There is a thin layer of white gauze covering the image. Generally speaking, the noise generated under high sensitivity is mostly located in the dark parts of the picture. Therefore, if you shoot outdoors in a well-lit place during the day, noise will not be easily generated, and there is no need to use a high sensitivity brightness such as ISO 3200. Instead, it will In indoor environments, low-light street scenes at night, etc., it is easier to use high sensitivity, thereby generating noise.

How to solve the noise problem? In fact, in addition to trying to control the shooting at low brightness and paying attention to the distribution of light and dark and environmental factors during composition, it is also good to use the built-in high-sensitivity brightness elimination function of the camera. Although the suppression effect is still limited, it can still provide considerable help in improving the quality of high-sensitivity brightness images.

Using too high a sensitivity can easily cause image noise and damage the image quality. Players can convert the image to black and white according to the situation. (ISO 6400)

Camera quality determines the available ISO sensitivity

In recent years, various manufacturers have been committed to improving high ISO quality. Take the single-lens cameras currently on the market in the past two years. , the available ISO value of APS size models generally reaches ISO 800, while the more expensive FF full-frame models reach ISO 1600, and some high-end models can even reach ISO 3200. In addition, among EVIL cameras in emerging markets, according to current tests, the Sony NEX series has the best high-sensitivity brightness, with usable ISO up to 1600. Although the average aperture of the lens configuration is not as high as that of other cameras, as the sensitivity increases, The available improvements further make up for the lack of aperture.

Low sensitivity can produce more delicate portrait quality.

(ISO 100)

Timing and methods of using ISO

In order to allow readers to more quickly understand the shooting themes and usage methods of ISO, the following author will give an overview of the applicable theme range of high and low ISO , and through practical explanations, readers can clearly understand the principles and application methods through the following examples, and truly learn how to use ISO. Use low ISO to keep images pure Generally speaking, low ISO can provide three major benefits to image shooting, namely high image quality, low noise and slow shutter speed. In terms of image quality, low ISO is better than high ISO in terms of contrast, contrast, and details of light and dark areas. It can make facial layers, hair, and peeling textures in the corners appear more delicate in the picture, showing the characterization. Stereoscopic image quality. When it comes to shooting landscape topics, the advantages of low sensitivity and low noise can also be used to make the night scene shooting at dawn and dusk pure and flawless. Even if you intend to output a large image, you don’t have to worry about the image quality.

Also, the benefits of low ISO are not limited to image quality. Sometimes the effect of low sensitivity is to slow down the shutter speed and capture a different image. Flavor. For example, for thin streams and waterfalls in mountains, you may need to use a shutter speed of less than 1/2 second to achieve dynamic water flow; if you are outdoors on a sunny day, you can also open the aperture wide (F2.8 ), lower the ISO to ensure that the shutter speed is within the limit range of the camera body (1/4000 second or 1/8000 second) to reduce the chance of overexposure and achieve a softer and more charming depth of field effect.

EVIL cameras mostly increase the available sensitivity to 800, which is beneficial for indoor shooting at night.

Generally, the available sensitivity for DC is mostly between 400 and 800.

If it rains, it is recommended to increase the sensitivity to ensure stable imaging. (ISO 400)

High ISO creates a new realm of images

For applications with high ISO sensitivity, although high sensitivity is accompanied by high noise, the image quality will also be relatively poor. However, for some dark and dangerous shooting environments, seeking the best before seeking the best, and using timely techniques to make high sensitivity assist and capture the decisive momentary image seems to be the part that photographers should pay attention to. share.

As the ISO increases, light will also form different amounts of light on the photosensitive component, allowing the shutter speed to increase with the multiple, effectively applying the principle of safe shutter and reducing the chance of hand shake. So what issues are currently applicable to high-sensitivity applications? Based on the author's past shooting experience, the shooting of concerts, wedding records, and some night scenes are the most important issues for high-sensitivity applications. As for the previous two issues, in order to avoid the dilemma of having a clear and bright subject but no background caused by turning on the flash, raising the ISO can not only increase the speed of light absorption and make up for the problem of insufficient background light in a timely manner, but also The charming light and shadow atmosphere of the scene was successfully preserved; as for the night scene, we mainly used the situation that needed to condense the moment, and used a high ISO and large aperture to freeze the beautiful scenery in front of us, such as the mountain starry sky and the Milky Way, night folk celebrations, Handheld city night scenes? etc., are all topics that can be controlled by high ISO.

If there is not enough ISO during night celebrations, the image will easily result in insufficient light at the scene. (ISO 1600)

Even if you are singing with the assistance of stage light, in order to ensure that the shutter speed is fast enough, it is recommended to shoot at a higher ISO.

(ISO 1600)