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ISO in Photography

What is ISO?

In photography, ISO stands for International Standards Organization. It refers to the standardized industry scale used to measure sensitivity to light. This can be used to measure a film’s sensitivity to light, but more commonly today, it is used to measure a digital camera’s sensor sensitivity to light.

ISO is part of the Exposure Triangle. The combination of Aperture, Shutter Speed, and ISO settings all affect the exposure results of images. These three settings go hand in hand when you are setting up your shot and getting the proper exposure.

Learning to master these three settings simultaneously can be overwhelming for many beginners when learning to shoot in manual mode. Rather than getting intimidated by all of the numbers, rules, and options, it’s easier to familiarize yourself with each setting individually first. This will give you a better understanding of how they all correlate when you are comfortable with taking the plunge into full manual mode.

It really does become second nature after you have done your research, put in a lot of practice, and have a genuine understanding of each individual setting.

ISO Chart

This ISO Chart/Scale explains how the different ISO settings (numbers) affect the overall exposure. The smaller the number, the less sensitive to light your camera will be. This means if you are shooting with low ISO numbers, you will need to have ample lighting. Otherwise your image will be underexposed. The less light you have to work with, the higher your ISO will need to be.

One thing to keep in mind when working with higher ISO settings, is that the higher it is, the greater the risk of getting grain/noise in your images. Generally, you want to shoot using the lowest ISO setting you can get away with.

The digital camera industry has made a lot of improvements when it comes to noise and grain, but depending on the camera you are using, it can be an issue when your ISO reaches a certain setting.

Example Of Different ISO Settings

This image shows how different ISO settings affect the overall exposure of an image.


As you can see, lower numbers cause the camera’s sensor to be less sensitive to light. Higher numbers result in the sensitivity to light being much greater, giving you brighter images.

Remember that small aperture settings and slower shutter speeds also let in more light. So it will be up to you to find the balance between the three settings.
For example, if you are shooting in a setting that requires shooting with fast shutter speeds to freeze motion (maybe a sporting event), you may need to bump your ISO up depending on the lighting. This will make up for the lack of light hitting your sensor because of the fast shutter speed.

The same holds true for aperture settings. The smaller the f/stop number you are shooting with, the more light you are allowing to hit the sensor. So you could likely get away with lower ISO settings.

There may be incidents where you are forced to shoot with higher ISO numbers. Such as museums or churches with low lighting that prohibit the use of flash. Or let’s say your child is blowing out the candles on his/her birthday cake and you don’t want to take away from the natural candlelit ambiance in the room by using a flash. Bumping your ISO up will enable your camera to pick up more on the natural lighting in the surroundings without having to use a flash.

All About Balance

When learning the art of shooting in manual mode, don’t overwhelm yourself trying to master blending these three settings together all at once. The more you understand each of the three exposure related settings individually (ISO, Shutter Speed, and Aperture), the more comfortable you will be when it comes to learning to find the proper balance between them as a whole.

Do your research on each setting. Learn what they mean, how they work, and how they affect different aspects of your image. Of the three, ISO is probably the simplest to get comfortable with and understand. This is because it really doesn’t affect anything other than exposure. Whereas shutter speed affects capturing motion and aperture affects depth of field, but both also affect exposure as well.

Invest the time to get a genuine understanding of all three, practice… then practice some more.

Learning to shoot in manual mode doesn’t have to be an overwhelming task! Just take the time and have a little patience learning your camera from the inside out. When you are producing well executed images by controlling your settings, you will be glad you invested the time and energy into the craft. No one becomes a pro over night.

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