November 9, 2023, 3:32 p.m. |
Reading time: 3 minutes
The ISO value is a fixed term in photography. If set incorrectly it can ruin a shot, but if set correctly it can produce excellent photos. But what exactly is ISO and why is it important? Editor Rita Deutschbein explains this in a new episode of TECHBOOK Basics.
First of all: ISO plays a role in all types of cameras, including system cameras, compact digicams, video cameras and smartphone cameras. The abbreviation stands for “International Organization for Standardization”, an international association of national standardization organizations whose basic task can be roughly compared with that of the DIN (German Institute for Standardization) in Germany. Standards bodies used to set ISO values to indicate a film’s sensitivity to light. Today the system is used more to determine the light sensitivity of the camera sensor.
That’s why the ISO value is so important in photography
Along with shutter speed and aperture, ISO is one of the three basic exposure settings when taking photos. The ISO setting has a huge impact on image quality. Set incorrectly, the wrong amount of light hits the image sensor. The result is overexposed or underexposed photos.
Depending on the lighting conditions, the camera’s ISO must be adjusted individually for each shot. In many current cameras, the software does this automatically. You can also regulate the value manually, for example using the professional mode on your smartphone. If desired, special effects can also be achieved with the exposure.
Also read: How does the bokeh effect work?
The optimal exposure setting
In principle: the lower the ISO, the more detailed the photo. However, the exposure should be sufficiently high so that there is no image noise and the resulting graininess. At high light levels, i.e. when the environment is well lit and the sun is shining, lower values are better. However, if it is rather dark, you should increase the ISO value to increase the camera’s sensitivity to light.
The following can be set as a guideline for the optimal ISO:
ISO 100: If the lighting is really good, a very low value is sufficient. An ISO of 100 is usually ideal outdoors on sunny days.
400: If it is cloudy or you are indoors, the ISO can and should be increased to up to 400.
800: An ISO of 800 is ideal for taking photos indoors without an additional light source.
ISO higher than 1000: Values from 1000 to 3200 are only needed in the dark with poor lighting.
You should keep in mind that the ISO setting also affects the shutter speed. For example, changing from 100 to 200 also halves the exposure time required. At low ISO values, it is often better to take photos with a tripod to prevent blurry photos. However, higher values also allow you to take photos handheld. However, a higher ISO is not always the right choice, as the image noise increases with increasing values. It is therefore better to slowly adjust the ISO upwards and rather open the aperture wider and increase the exposure time.