What is ISO in photography?

The abbreviation stands for ”International Organization of Standardization”. It is the regulating body that controls sensitivity ratings for camera sensors, as well as other things. In simpler terms, ISO in a camera option that will either brighten or darken your photography. Increasing the ISO number will make your pictures brighter and help you capture good shots in darker environments.

It’s important to have such a standard because it allows people to shoot the same ISO on different cameras with the same values.

ISO in Traditional and Film Photography

In film photography, ISO (or ASA) is the indicating of how sensitive a film is to light. Just as for digital photography, the value was measured in numbers. The lower the number, the lower the sensitivity of the film to light (and hence the less grainy the image produced). But people who used this kind of hear didn’t have the privilege to change this setting whenever they wanted. They just had to shoot until the film was done, after which they could opt for one with other ISO values.

Film photography

ISO in Digital Photography

In digital photography, the term ISO refers to the image sensor’s sensitivity to light. The lower the number, the less sensitive the image sensor is to light.

As you may have noticed, the higher the ISO the more grainy an image becomes. This is why it’s often not considered to be good practice to only adjust the ISO in the absence of light. Most photographers (depending on the situation and their camera) will have to lower their shutter speeds, aperture and raise their ISO. This happens in order to compensate for the absence of a significant light source without making the image appear extremely grainy.

An ISO of 100 is generally accepted as the standard ISO. It will result in very crispy photographs with little to no grain. Most people tend to keep their digital cameras set to ‘Auto’. It allows the camera to select the most suitable ISO depending on the conditions in which they are shooting. The camera will try to keep the ISO as low as possible, as would a photographer when manually adjusting the settings (in most cases).

Digital photography

As a part of the exposure triangle, when you adjust the ISO it changes the exposure of your photograph. This means you may be more able to adjust the shutter speed and aperture.

For example, if you’re shooting in decent daylight and are aiming for a well-exposed shot, you could choose to raise your ISO slightly. Doing so, you will be able to increase your camera’s shutter speed. The purpose of increasing the shutter speed is so that you can capture movement such as sports. However, if you were to raise the shutter speed without adjusting ISO, the result would be an image of lower brightness.

When choosing ISO, I generally ask the following questions:

Light: Is the subject already well lit?

Grain: Do I want to avoid having any grain in my image?

Tripod: Can I use a tripod?

Situation: What am I photographing? A portrait or action sports?

If there is an abundance of light, I would prefer to have as little grain as possible. So I will use the lowest possible ISO and adjust my aperture and shutter speed. This is the best way to ensure that my image is still bright enough.

On the other hand, if it is dark, I will need to increase my ISO to ensure the image is still well-lit. This will still allow me to use higher shutter speeds to avoid capturing a blurry image.

When to use low ISO

The advice everyone gives around this subject is pretty simple – stick to the lowest ISO as much as possible. As mentioned before, this is the standard because it will not make your photos grainy. If you’re shooting in environments that have plenty of light, there’s no need to change this setting.

Even for darker places, in the cases you’re able to keep your camera steady – by using a tripod, for example, you can keep your base ISO. This can be done because you can brighten your picture via long shutter speed instead. Be careful, though, because if there’s any movement involved, the long shutter speed option will make everything around look like a ghost.

People who shoot portraits will not need to change these values. Their work requires a lot of light on the subject. Being into a niche that’s safe enough not to damage the quality of your photos by playing with the ISO values can bring a lot of benefits. You can market your business in such a compelling way that you’ll gain a lot of customers.


When to use high ISO

Not only deprived of light environments require a high ISO. Even if you’re advised to use the lowest value of it as much as you can, there can be some advantages for high ISO as well. When you’re photographing movement, you can adjust the ISO value to a higher one, in order to really freeze the moment.

If you’re into horse photography, for example, you know that working with an animal that doesn’t understand your language is pretty difficult. It will move around or even be agitated. So taking a still picture of it is not as simple as you may think. By using a higher ISO you will capture a great, sharp shot. Using low ISO will cause motion blur, which will definitely ruin a great picture. Otherwise, the same story goes for dark locations. They will make you raise the ISO value in order to take a cool shot.

Movement pictures are very impressive and looked for by people who need to work with such images. For example, those who need stock pictures for different purposes. This is why becoming good at this can bring you a lot of opportunities. Regular people or even the ones that work with social media, don’t hire a photographer to take a picture of a flying bird. But they look for such things on stock photo websites, so this can be your chance. Learn how to make money out of selling your photos online. This can be an extra boost for your motivation on getting started in this area.

High ISO

Learning these things can be very helpful if you’re thinking of becoming a professional photographer or even starting a business. It’s important to have control over any type of information that will bring you closer to being the best.

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