Photography basics for dummies – Manual settings 2 - ISO Settings

In the second part of learning Photography basics we are going through ISO settings.

ISO stands for International Organization for Standardization.  This terminology is carried over from the Film Camera days where ISO value represents the film’s sensitivity to absorb light.  In the modern day DSLR the same terminology is retained for easier understanding on the behavior of light in Photography.

Let me get you the basics of ISO for you.  Every camera has a Base ISO value, say ISO 100.  This is the lowest ISO setting possible in the camera, the values further increments in multiples of 2 to a max threshold as supported by the camera.  The ISO values would look like: 100, 200, 400, 800, 1600, 3200, 6400, 12800….. etc. Each increment doubles and increases the sensitivity of light at the camera's sensor.

Note: Higher the ISO values will result in excessive noise and grains on your output image. This is something you have to sacrifice when attempting low-light photography without flash.

Working with ISO settings: For beginners like most of us, we can always go with the “Auto ISO” setting.  But I suggest you attempt photographing a given object with different ISO settings to easily understand its working.

Here’s an image to help you understand the overview of how changes in the ISO settings can vary the output image. The green check denotes the right setting.  

Scenario 1 - Day Bright Sun Light.

Setting ISO at 800 gives you too much exposure than desired. Moving down to ISO 100 would cut too much light.  Either ISO 200 or 400 would give us the best result.

Scenario 2 - Night Low Light

As I do not intend to use flash for this image, it is needed that I bump up the ISO to the highest possible value at the same time keeping check on the grain and noise.  ISO 800 gives me the desired brightness in the scenario. I could push for ISO 1600 for brighter image, however it would result in high noise and grain.

When should you make changes to ISO settings?

1.  When your image appears too bright or too dark.
2. When noise or grains appear in your image.
3. When you attempt to capture a picture in the dark without flash.
4. When you attempt to capture an object in motion and your images appear blur.

When should you increase your ISO setting?

1. When your image appears too dark. Increment the ISO in steps until you see the desired tone in the preview display.
2. When you try to shoot in low-light without flash, bump up the ISO few steps.
3. When you try to shoot an object in motion and it appears blur.  Increment the ISO values in this scenario to increase the light sensitivity; this in turn allows you to shoot faster. You’ll learn more about this in when reading about Shutter Speed.

When should you lower the ISO setting?

1. If you images appear too bright.  Lower ISO value, this cuts the sensitivity of light on the sensor.
2.  If your image has too much noise or grain.  Lower the ISO, this will reduce the grains but doing so also reduces amount of light, compensate this by using flash or increasing Shutter speed.
3. When you want to shoot a long-exposure shot.

Hope that went easy!  To be honest, not an easy ride on the ISO settings, you can only learn when you’re experimenting through the settings.

Our next stop will be Shutter Speed……

Further Reading

Part 1 : Basics and Aperture Settings

Part 3: Shutter Speed and Tips