Welcome to the first post in my series, 40 Photography Experiments!
Each day’s experiment is meant to help you learn about your camera, about photography or about how you see light and the world around you.
Getting started with ISO
Today we are starting things off with a critical piece of the Exposure Triangle: ISO. ISO is your digital camera’s sensitivity to light. This works in conjunction with Shutter Speed and Aperture, both of which control how much light comes into your camera, to create your awaiting masterpiece.
Some photographers will tell you to never use the highest ISO your camera can handle. Others may tell you to only use something below ISO 400 and never dare to go higher.
I’m here to tell you to figure it out for yourself.
You can first read through my post on ISO if you need more background information.
Higher ISO comes with issues
Basically, as you increase your ISO you will see more and more noise in your images. Noise is usually considered ugly (unlike grain, which some consider pretty. Have I mentioned how subjective photography can be?). How much you can stand is entirely up to you.
Pictures that you want to be share, maybe even print, and contain rich colors and smooth gradients should have very little noise. While other pictures, such as a photo of your kid on a dark stage for a school play, can risk more noise in order to help increase your shutter speed so there is no blur. It depends on the subject matter and your tolerance.
But first, let’s get you accustomed to your camera so you know just how much noise it creates. Not all cameras and phones are the same and I would be remiss if I just told you “Never go above ISO 400” when, in fact, your newer camera can create pretty pictures at ISO 1600.
Smartphone Note: Not all phones allow you to change your ISO. You can still run the experiment below so you know what your images will look like in similar lighting conditions.
Here’s the experiment you can run:
- In a darkish room with a table, turn on just one light. Something not too bright (although you can see the effects in broad day light, a dark space is better to see the results).
- On the table, set up a still life of various objects. Bring in something white, something black and then a variety of colors. Grab what you have at hand, as I tend to do when writing about photography (see image at right). You don’t need to represent the rainbow here, just a variety. The black and white ones are most important.
- Now set your camera at the other end of the table. Focus on an object and lock focus (change to manual focus mode). It’s important that your camera doesn’t move during this experiment. You can use a tripod if you like.
- Set your camera to Aperture Priority.
- Set your aperture to f/8.
- Adjust your ISO to the lowest number it can achieve. This will likely be 100 or L1.0. Some cameras go lower and some go higher. Just get as low as you can go.
- Turn off your flash.
- Take a photo of the scene.
- Now change your ISO to the next full stop. If you started at ISO 100, then 200 is your next stop (a stop, in ISO terms, will be a doubling or halving of the number, mathematically speaking). If you were on L1.0 then go to ISO 200.
- Take another photo.
- Move up to the next full stop (i.e. ISO 400 from ISO 200).
- Take a photo.
- Repeat this pattern until you have gone as far on the ISO scale as your camera will go.
You’re done shooting!
When you are finished, check the images on your computer and zoom all the way in to 100%. You are looking for noise in the dark areas.
Noise is a discoloration or fuzziness and takes away from the smoothness we normally see in colors. Here’s an example of extreme noise (ISO 12,800).
See all that crappy, fuzziness? That’s noise. It takes away from details and makes this unpretty.
What you will see on your computer when examining the files is a progression from not much noise at low ISO to more at higher ISO.
It’s your choice
It’s up to you to decide just how much noise is too much noise. It might be at ISO 800. It might be at ISO 1600 and, for some point and shoots, it might be at ISO 400.
It’s important to learn how much is too much for you. You can use that knowledge when out shooting as a higher ISO usually means a higher shutter speed (to cut down on blur). The important question here is, “If I increase my ISO to X to cut down on blur, will I be sacrificing too much image quality?”
In the case of a nice scenic mountain scene, I wouldn’t go much higher than ISO 200. But when my kid is on stage for a play, I often use ISO 6400 to make sure she isn’t blurred. I know I can touch things up in the computer after.
The rule of thumb is to use the lowest number ISO you can ‘afford’ to use (given the lighting conditions). And at the same time, this test will help you know where you tolerance stands for high ISO conditions.
Tomorrow’s topic will be: Focus Modes
Questions? Pop ’em like Pez in the comments section below. or email me at email@example.com.
40 Photography Experiments is a series written by professional photographer Peter West Carey and is available for free to all photographers. The series is a companion to Photography Basics – A 43 Day Adventure, free lessons on getting started in photography. Subscribe here to receive all the updates and bonus material.
If you enjoy the series, consider learning photography first-hand on a professionally led international photo tour in Nepal or Bhutan. More information can be found at Far Horizon Photo Tours.