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Auto ISO

ISO Settings

Part 2

Taking a look at Auto ISO

Auto ISO: what is it and is it useful? 

What is Auto ISO?

Auto ISO was introduced into digital cameras several years ago to help photographers maintain the choice of settings to arrive at a correct exposure. Turning on that feature allows the camera to push the ISO up when it calculates the settings (for shutter speed and aperture) are getting too low for a good picture. Almost all new Digital cameras (including new DSLRs and mirrorless cameras) have an Auto ISO setting.

Is Auto ISO really useful? 

We’ve seen that we can control exposure by using Shutter speed, Aperture, and ISO. The usual method is to set the ISO, select what shooting mode you want to use and then set the shutter speed and/or aperture to achieve the right exposure.

When manufacturers introduced Auto ISO for the first time, many photographers didn’t like the idea of leaving it to the camera to set the ISO. And I would say they were right!…to a degree.

Normally you don’t want to shoot at a high ISO because your photos can get grainy (noisy); but with the new sensors you can easily shoot images at 1600 ISO or even higher, with no noticeable noise!

ISO Setting

This image is shot at 2000 ISO, with virtually no Noise

Does this mean I can shoot all of my images at higher ISO settings?

No. This is not a good idea and for several excellent reasons. The most important reason is at a higher ISO you reduce the Dynamic Range of the sensor, which means the camera can not capture as many details in shadow and highlight areas. Other disadvantages of higher ISO can be listed as lack of sharpness, chances of getting artifacts in image (Pixilated edges), etc.

ISO Settings

ISO settings at 100

ISO Settings

ISO settings at 6400

ISO Settings

ISO 100 left image and ISO 6400 at right

The real value of Auto ISO is it can – in specific situations – help you to shoot sharper and better images faster, with less fiddling around with shutter speed or aperture.

Here are some tips for using Auto ISO:

Example 1: you are shooting a sporting event, and want to keep your shutter speed at 1/1000s and the aperture at f2.8. But some of the action happens in the shade and the others in the light. Set your camera to Auto ISO and it becomes your best assistant in this case. It will change the ISO to maintain the shutter speed and aperture combination, regardless of whether your subject is in the shade or in the light.

Auto ISO

Camera set at Auto ISO and this photo was taken at the bright side of the field

Auto ISO

In Auto ISO, Camera maintained the shutter speed and aperture but increased the ISO to capture this shot.

Example 2: You are photographing children playing in a playground. If you shoot in manual mode and set the shutter speed and aperture, you don’t have to be worried about your exposure; the camera will set adjust the exposure via Auto ISO, regardless if the kids are playing in the shadow or the sunshine!

Set camera to Auto ISO and camera will compensate ISO to maintain the shutter speed and aperture

When it got cloudy, Auto Iso adjusted the ISO to keep the exposure the same

Set camera to Auto ISO and camera will compensate ISO to maintain the shutter speed and aperture

As the light changed, Camera reduced the ISO and you can shoot with faster shutter speed to freeze the action

That is all for now. We love to hear from you. Do you have questions or a topic you’d like more clarification on?  Drop us a line and we will answer your questions in our weekly Photography posts.

Digital Camera Bootcamp is an eight week program which includes two field trips. It is developed for beginners and intermediate photographers. In this workshop you have a chance to try Auto ISO in the day time field trip, and fixed ISO in Night time photography to unleash the power of your camera.

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