What is the best choice of sensitivity? What is sensitivity

ISO speed is an internationally standardized standard for measuring the speed of film used in traditional cameras, which reflects the speed of the film (in fact, the speed at which silver reacts with light). Conventional cameras can choose low-speed, medium-speed, or high-speed film with different ISO sensitivities to shoot according to the specific conditions of the shooting location. In the case of digital cameras, film is not used, but the intensity of the incident light is sensed by the image sensor CCD or CMOS and the associated electronic circuits.

The concept of ISO sensitivity was introduced in order to unify the unit of measurement with the film used by conventional cameras. Similarly, the ISO sensitivity of a digital camera also reflects the speed at which it is sensitive. For every time the ISO value increases, the speed of light sensitivity increases by a factor of 1.

For example, the sensitivity of ISO200 is 1 times faster than that of ISO100, and the sensitivity of ISO400 is 1 times faster than that of ISO200, and 4 times faster than that of ISO100, and so on.

Looks like you've asked two questions.

Hehe. The choice of ISO actually depends on the actual situation, and it takes a lot of words to analyze it.

Thankfully, I've written many, many words.

I won't repeat it anymore.

Check it out on my blog.

Your question is equivalent to: I drive a car, what speed should I choose? I have a range of 20 km h to 220 km h, and 10 m h to 160 h here, what speed should I choose to drive?

Sensitivity refers to the sensor's sensitivity to light coarsely

Based on the ISO value of the sensitivity, we can understand how well the film or sensor perceives light. An ISO 100 sensor requires twice the amount of light to achieve the same level compared to ISO 200.

In order to get 2 times the amount of light, the shutter speed needs to be reduced by half (e.g. from 1 60s to 1 30s) or the aperture increased by 1 stop (e.g. from f to f 4).

Lowering the shutter speed is obviously not a good idea, as it increases the risk of blurring. So why can't we always use the highest sensitivity setting?

It's not just noise

The latter two issues are generally less noticeable than noise. Increased noise reduces sharpness and loss of detail. Iwaeda's reduction of contrast affects detail resolution in highlights and shadows.

Noise is always negative?

A lot of time has been spent studying the difference between low and high sensitivity**. It's hard to say which one is more appropriate – having some noise isn't always a bad thing and might make ** feel better.

Different cameras have different levels of noise.

Yes, different cameras have different capabilities to deal with noise, and the high sensitivity level of cameras has also evolved greatly in recent years. If you're using a portable digital camera, ISO 400 noise is likely to be about the same level as other cameras' ISO 3200. And if you use the best DSLR camera, even above ISO 800 is available.

Nowadays we may enlarge the maximum size on the screen to check. Don't forget, though, that the noise level should be at the actual size of the **. Honestly, what are the chances that you'll use a bigger ** than an A4?

It's mine. What is the maximum sensitivity that the camera can tolerate?

Shoot a set of different sensitivity settings with your camera** and check the noise level at common sizes to determine the maximum sensitivity that the camera can tolerate.

The effect of low sensitivity

In some cases, a small sensitivity must be used. Here are 3 examples:

1. You need to use a shutter speed of less than 1 2s to shoot running water. In this case, a minimum sensitivity is required, and if the minimum aperture is not sufficient, a neutral gray lens is also required.

2. Outdoors on a sunny day, you need to use a wide aperture (such as f to get a shallow depth of field effect. Most cameras should not exceed 1 4000 s or 1 8000 seconds of shutter speed, and try to set the sensitivity to ISO 100 or 50. If this is not sufficient, a neutral gray lens is required.

3. When using a flash. Even with the smallest output, the brightness of the flash is impressive. Use a minimum sensitivity, and increase the flash output if it's insufficient.

ISO is the size of the sensitivity, so to speak, if the environment is dark, the illuminated ** will also be dark, and improving the sensitivity is ISO ** will be much brighter. But ISO has a finch grinding front***, that is, if you raise it too much, there will be a lot of large particles of noise caused by the current, and there will be a lot of color spots, which looks very rough and rough.

When shooting in the dark, it is necessary to increase the sensitivity of the shutter speed in order to maintain the shutter speed. However, the higher the sensitivity, the more noise there is, which can be understood as the worse the image quality.

What is ISO?The great god of photography popularizes the sensitivity and his understanding of photography!

the sensitivity of the film (film) to light; Low sensitivity refers to soft film (film) below ISO 100, medium sensitivity refers to ISO 200 800, and sensitivity control.

The high sensitivity is ISO 800 or higher. For example, ISO 200 can be used for cloudy days, ISO 400 or higher for dark environments such as stage and concerts, and digital cameras have a similar function, which changes the ISO value by changing the magnification of the signal amplifier in the sensor chip, but when the ISO value is increased, the amplifier will also amplify the noise in the signal, resulting in coarse and fine particle images.

For a long time, there were contacts on the film that allowed the camera to automatically recognize the ISO, if you use a camera with an automatic ISO film recognition function (there is a metal strip that recognizes the ISO in the box containing the film), you don't need to set the ISO, the camera will automatically meter according to the ISO value of the film, if you don't have this function, you need to set it manually, so some cameras have an ISO dial on it. Generally speaking, ISO100 film is cheaper, and the higher the ISO, in addition to the higher the standard, there is also a disadvantage, that is, the imaging quality is not as high as that of the film with low ISO. However, in order to achieve a higher shutter speed, sometimes the image quality will be sacrificed to use high ISO film.

This is more professional, from the perspective of light. We have the following aspects.

Light sensitivity, light intensity, light flow, light aberration, etc., these are the same terms as color, etc.

Light sensitivity, which is equivalent to speed.

Check the book specifically, there will be a more detailed explanation on it.