Introduction to photography ISO sensitivity operation skills

Introduction to photography ISO sensitivity operation skills

The sensitivity of digital camera is an index similar to film. In fact, ISO of digital cameras is realized by adjusting the sensitivity of photosensitive devices or merging photosensitive points, that is, by improving the sensitivity of photosensitive devices or merging several adjacent photosensitive points. Let's take a look at the ISO sensitivity operation skills of photography introduction.

Photosensitive devices have a kind of reaction ability and are fixed. There are two ways to improve the ISO of digital cameras:

1, forcibly improving the brightness and contrast of each pixel;

2. Using multiple pixels * * * can complete the task that only one pixel is needed.

The ISO sensitivity of digital camera is equivalent to the negative sensitivity of traditional camera, which also reflects its photosensitive speed. ISO can be changed at any time according to the change of shooting environment and light. In addition to directly setting ISO 100 to 12800, the ISO sensitivity of Canon EOS 5D Mark III can also be extended to ISO 50(L), ISO 5 1200(H 1), and ISO 102400 (.

set up

Setting ISO sensitivity on Canon EOS 5D Mark III is very fast and convenient. Press the ISO key on the fuselage, and the ISO sensitivity setting interface will be displayed on the LCD screen at the top of the machine. Just turn the main dial and directly select the ISO value you want to use. In addition, pressing the speed control button on the back of the fuselage can also directly adjust the ISO value on the speed control screen.

operational approach

1. Press the speed control button to display the speed control screen.

2. Use the multi-function control button to select the parameters to be adjusted. Turn the main dial or speed control dial directly to change the parameter setting.

3. Press the Settings button to enter the detailed settings page, and then turn the main dial or speed control dial to change the parameter settings.

Set automatic ISO range

When using Canon EOS 5D Mark III, if the sensitivity is set to automatic, it means that the camera will automatically control the sensitivity. Once the current ISO value cannot achieve the best exposure effect, the camera will automatically adjust the ISO value within the set maximum ISO sensitivity range.

Canon EOS 5D Mark III allows users to set the automatic ISO range, so that users can control the sensitivity according to their own requirements for image quality. Because Canon EOS 5D Mark III has strong noise control ability, if you want to get fine image quality, you can set the automatic ISO range to ISO 100 to ISO 1600 to meet the needs of daily shooting. Under some extreme shooting conditions, even if the highest sensitivity is set to ISO 6400 to ISO 12800, although there will be some slight noise and noise, the picture texture is still within the acceptable range.

operational approach

1. Select the ISO sensitivity setting in the shooting menu.

2. Select the lowest shutter speed, and then press the Set button.

3. Select the maximum ISO value, and then press the Set button. Then use the multi-function control button to adjust the value, and confirm the operation after the adjustment is completed.

Set the minimum shutter speed.

operational approach

1. Select the ISO sensitivity, select the automatic ISO range in the shooting menu, and then press the Set button.

2. Select the lowest shutter speed, and then press the Set button.

3. Set the minimum shutter speed in the menu. If the shutter speed is lower than this value, the ISO value will automatically increase.

Relationship between ISO sensitivity and shutter speed

In the same shooting environment, ISO sensitivity is directly proportional to shutter speed. When the ISO value increases by 1 times, the photosensitive speed also increases by 1 times.

For example, the sensitivity of ISO 200 is higher 1 times than ISO 100, ISO 400 is higher 1 times than ISO 100, and so on.

Therefore, in order to ensure a high enough shutter speed, you can set a high ISO value when shooting with a telephoto lens in a low-light environment with hand-held photography and high-speed motion to supplement the subject. When shooting with a tripod, it is recommended to set a lower ISO sensitivity to obtain a finer picture quality.

Aperture priority, f 1 1,115s, ISO 6400, focal length 70mm, exposure compensation-1EV. When the sensitivity is increased by five steps to ISO 6400, the shutter speed is correspondingly increased by five steps to115 seconds, and the vehicles and pedestrians at the intersection are relatively stationary, which is not what we want.

Aperture priority, f 1 1.4 seconds, ISO 100, focal length 70mm, exposure compensation-1EV. The sensitivity is reduced to 1, set to ISO 100, the shutter speed is doubled to 4 seconds, and the trajectory of vehicles and pedestrians at the intersection is longer, which is not what we want.

Aperture priority, f 1 1.2 seconds, ISO 200, focal length 70mm, exposure compensation-1EV. Under the setting of ISO 200, the shutter speed is 2 seconds, which can properly represent the busy scene of urban intersections in a dynamic and static way.

ISO sensitivity and photo quality

ISO sensitivity not only affects the shutter speed, but also affects the image quality. Under the high ISO setting, the image sensor CMOS takes light as the receiving signal, which will cause noise and noise spots in the image during receiving and outputting. Although Canon EOS 5D Mark III has high ISO sensitivity noise reduction function, the higher the ISO sensitivity value, the more obvious the noise on the screen. In other words, a high ISO sensitivity setting will reduce the image quality. Therefore, when increasing the shutter speed by increasing the ISO sensitivity, we must weigh the pros and cons and avoid using too high ISO value.

Under the setting of ISO 100, there is less noise and better image quality.

Under the setting of ISO 6400, obvious noise and noise began to appear, and the image quality deteriorated.

When increasing ISO sensitivity to improve shutter speed, we should still weigh the pros and cons.

High ISO sensitivity noise reduction function

Canon EOS 5D Mark III provides long exposure noise reduction function and high ISO sensitivity noise reduction function in the shooting menu. The long exposure noise reduction function is used to reduce the noise and noise on the screen when the exposure time exceeds 1 sec.

It should be noted that after turning on the long exposure noise reduction function, the time required for taking pictures will double! Therefore, when shooting a night scene with exposure for several seconds, if shooting with JPEG file, it is recommended to set the long exposure noise reduction function to automatic, and the camera will detect and judge whether noise reduction is needed.

For exposure shooting over 10 second, it is recommended to use RAW file and turn off the long exposure noise reduction function to avoid delaying the shooting opportunity due to noise reduction. The software can be reused for noise reduction in the future.

The high ISO sensitivity noise reduction function allows you to set the internal noise reduction performance when shooting with high ISO value, including four options: standard, weak, strong and off. When the high ISO sensitivity noise reduction function is turned off, the details on the screen are clear, but there are obvious noises and noises. When the noise reduction function of high ISO sensitivity is strong, noise and noise spots are effectively suppressed, but the detail clarity is reduced. Therefore, when taking pictures, we should avoid excessive noise reduction, which will make the picture lose details and reduce sharpness. Usually, it is set to low or standard.

operational approach

1. Set the noise reduction function in the menu.

2, high ISO sensitivity noise reduction function.

3, long exposure noise reduction function.

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