The third essential creative option is the ISO setting in your camera.
The ISO has one function, to make your image appear brighter. By raising the setting, you increase the illumination level of the image. Keep in mind that you are not actually adding any real light to your picture, you’re just making the final image brighter.
The ISO
To get a better idea of what it offers, let’s look at a simple problem and solve it with the ISO.
Let’s say for a moment that you chose your aperture with purpose (controlling your depth of field perfectly), picked your shutter speed with intent (as to freeze the action in front of you) yet when you take the picture, it appears dark. No problem. You could simply raise the ISO setting in-camera to make the image appear brighter.
Problem Solving With Your ISO
Familiarization Assignment
- Switch your camera to manual control.
- Locate your ISO control (check your camera manual, if necessary).
- Choose the highest ISO setting your camera affords.
- Choose the lowest ISO setting your camera affords.
- Choose ISO 200.
- Choose ISO 400.
- Choose ISO 800.
- Choose ISO 1600.
As you can see, camera manufacturers don’t make it hard to find or change the ISO.
What is the ISO exactly (and what’s it doing to my picture)?
This ISO isn’t actually a thing in your camera, it’s a group a people.
In 1946, 65 delegates from 25 countries met in England to discuss the future of standardization in the world. Their goal was to break the barriers of international trade and create universal measurement systems that would offer the same quality between products and services world wide. The next year, the International Organization for Standardization (the ISO) was born and in 1951 their first standard (ISO/R 1:1951) was published.
In 1974 a very specific ISO standard (a mathematical formula) was published defining scales for the sensitivity of black and white negatives and color reversal film. It was a numerical system that manufacturers could use to identify their films sensitivity to light. Higher ISO numbers meant the film was more sensitive to light. Of course the entire film sensitivity issue in photography (and those assigned formulas) were radically changed in 1998 (revised in 2006 and corrected in 2014) to address the digital age. ISO 12232:2006 specifies the method for assigning and reporting ISO speed and latitude ratings, standard output sensitivity values and recommended exposure index values for digital still cameras. This is (by the way) the very thing you’re adjusting when you change the ISO in your camera. You’re changing the math your camera uses to interpret the light you’ve captured.
Of Speed, Sensitivity and Noise
When you choose higher ISO settings you are (in essence) asking your digital camera’s processor to take a mathematical guess at what the scene would look like if there were more light available and then to make that brighter image happen. The higher the ISO setting chosen, the more aggressive the math becomes. This mathematical ‘guessing’ is called interpolation and offers options unheard of in the past.
With higher ISO settings in play, you can shoot in places that would prove difficult without an eclectic collection of extra gear (like flashes, specialized modifiers or a tripod). You can shoot sports without worry of blur, you can shoot indoors without the need for a flash. You can raise the ISO setting so high, that you can shoot at night while hand-holding the camera and still get an image that’s in focus.
The only drawback is that very high ISO settings tend to produce less than satisfactory results for many shooters. A loss of contrast, color and sharpness usually occurs, along with something called digital noise. You can equate the effect to the grain we would see should we choose to over process our film (back in the day) or to use very high ISO rated film. This noise however is a small price to pay for a photo that’s in focus.
Our suggestion is to keep the ISO as low as possible unless it needs to be raised, but never be afraid to raise it. An in focus and slightly noisy photo of your family’s trip to an aquarium is always better than a collection of blurry ones.
In Review
The ISO (the International Organization for Standardization) is a world wide organization that creates measurement systems and standards to ensure the same quality between products and services world wide. By changing which ISO formula the camera uses, you can change the illumination level of your image. Higher ISO numbers make it brighter, lower ISO numbers make it darker.
Key elements:
- As you raise the ISO setting in your camera your image becomes brighter.
- With higher ISO settings your image is degraded. You will lose color, contrast and detail.
- It’s up the artist making the decisions as to how much noise in an image is acceptable.
Next: Essential Creative Option #4 – The Flash
This is post #5 of 16 of In Camera Magic: The 12 Essential Creative Options, a free online photography course for creating spectacular images right in the camera.