ISO is one of the 3 most important things that impact the image and its quality. The other key things are aperture and shutter speed, which affect the exposure of the photograph. Balancing these three factors can yield the perfect shot.
This article will make ISO simple and easy to understand so you can use in your photography and create stunning photos!
ISO stands fro International Standards Organization, which sets the standards of sensitivity for camera sensors.
In the days of Film, ISO was written on the film in numbers ( like 100 ISO, 200 ISO, 400 ISO, 800 ISO etc.) The most common Kodak or Fuji films were of ISO 100 or ISO 200. An ISO 400 rated film was considered a fast film!
The ISO Numbers denote the sensitivity of the film towards light.
Lower ISO numbers mean that the film is less sensitive to light, and thus would take longer to get exposure. But the grain is much finer, and you hardly see any grain, even if you blow up the print to large poster sizes.
A higher ISO means that the film is extremely sensitive to light, and will expose much faster, but will produce a larger grain… meaning that if you blow up the image to a larger size, you can see the graininess of the image. But at least you are able to take the shot.
A 400 ISO film is twice as sensitive to light compared to a 200 ISO film.
Today, most of the digital cameras allow you to tweak the ISO setting. And Digital SLR (DSLR) cameras will have a dedicated button to tweak the ISO setting.
Why use a High ISO setting?
Because at a higher ISO setting, the camera sensor is extremely sensitive, it exposes even at low light. This allows you to take snaps indoors, where there is low light, orl when the subject is moving fast.
Consider this example: you want to take the photo of a boy on skates, as he moves in front of you.
Since the boy is moving on skates, the shutter speed will have to be fast to capture the boy clearly or else the image will come out blurry.
We have now set a fast shutter speed, the light entering the camera will be much lesser, as the shutter opens for only a fraction of a second. With less light, the image will be dark, and we won’t be able to see the boy’s face or features clearly.
To compensate for this, we can increase the ISO rating of the sensor, which will make the sensor extremely sensitive to light, and whatever light enters the camera will be used to expose the image.
So with bumping the ISO higher, we can get a clear and bright shot. But with higher ISO, we get a bit of grain (or noise). However, at-least we are able to capture the shot, which otherwise we might not have been able to.
Other examples where you could tweak the ISO are:
- When you want to take a slow shutter shot, which shows some motion – like water flowing in a river. To show the flow of water, the camera shutter needs to be open for a longer time. When the shutter is open long, more light will enter the camera and may over expose the shot.Thus, we can reduce the ISO, so the sensor becomes less sensitive to light, and we can capture the motion of the water.An added advantage with this is that with a lower ISO, the image comes out very clean, with hardly any grain, and looks great even if blown up to a much larger size.
But keep in mind that with a slower shutter speed, you may have to use a tripod or a monopod, or else the image will be blurry.
- For taking portrait shots, it is recommended to use a good Portrait Lens like the Canon 50mm 1.8 lens, which has a larger aperture, allowing more light to come in. Even with more light, you can lower the ISO, reducing grain, and still achieve a great snap.
- For indoor activity with poor lighting, shoot at fast shutter speeds to successfully capture moving subjects, without any blurring effect. This is done by using a higher ISO setting (usually 3200, 6400 or even 12800 in extremely low light.)
- Shooting night landscapes is much easier with a fast shutter speed, if the ISO is set to a higher setting also.
Most photographers look at the snap they have taken on the camera’s display, which is usually quite small to see the minute details, color, and graininess. Remember to zoom up a bit to see the actual size of the image to get a better idea about the quality of the image taken.
Have you tried the ISO setting of your camera? Do let us know your experience with ISO, and if you encountered any problems. We can attempt to answer your queries here, and help you capture stunning photos with ease!
Vinai is an avid photographer, who loves to take photos as a hobby, and experiment with various settings.