ISO sensitivity. Basic knowledge
ISO sensitivity. Basic knowledge
Anonim

The concept of what ISO sensitivity is is one of the basics. It is necessary even for a novice photographer, of course, a professional cannot do without it.

ISO values in modern cameras
ISO values in modern cameras

ISO sensitivity is a measure of how a camera's sensor perceives the light it receives. A high ISO level makes it possible to take pictures in low-light areas. Just a few years ago, ISO speed was not a property of the camera, but of the film itself, and to capture multiple shots in varying light levels, the photographer needed to change film to find the best one. Today, both professional (SLR and mirrorless) and amateur (digital) cameras have manual and automatic ISO control, which makes it possible to take shots with different light sensitivities by recording them on the same memory card.

Low and high noise levels
Low and high noise levels

When the lighting is insufficient for correct exposure, it is not always possible to use an external (and internal) flash. It is in such cases that you have to change the ISO value to a higher one or switch to its automatic setting.

In addition, level adjustmentISO sensitivity can help when it is impossible to increase the shutter speed and in the absence of a tripod. In this case, using a higher ISO setting will speed up the shutter speed.

However, it would be too easy if constant use of high ISO values did not have a side effect. After all, matrices for cameras are designed in such a way that increasing ISO increases their sensitivity. And in this case, not only more light is recorded, but also the so-called noise.

Effect of ISO value on image quality
Effect of ISO value on image quality

Determines the range of optimal ISO values for camera sensor size. The larger it is, the lower the noise level even at maximum ISO values. In cameras (both "reflex cameras" and "soap dishes") today, a matrix of at least 2.3 is mainly installed.

This should be understood in order to avoid a fairly common misconception that sometimes happens to beginners: you should not think that the more megapixels a camera has, the better it is. Just the relatively high number of megapixels that some camera manufacturers are trying to put into the sensor can significantly reduce the quality of images in terms of excessive noise. Therefore, do not blindly believe advertising.

Thus, shooting at maximum ISO values is possible only when it is justified:

• If you have a choice between whether to take a picture with noise or not at all.

• When the shooting conditions do not allow the use of a flash.

• When you plan to print small photos, usewhere the noise is barely noticeable.• If it is possible to reduce the noise level with processing.

And when shooting outdoors with sufficient natural light, the best choice is the ISO sensitivity set to the minimum value. This is how you get the best shots.

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