What the heck is ISO?? There’s a good chance you’ve never even heard of it, let alone know what it does. Back in the days of film it was just a number on the box for me and I knew that ISO 400 film was for use in darker areas and ISO 100 film was for outdoor photos. Because that is what the box told me lol. Are you having an “oh, ya, I remember that” moment? Come on I’m not old and the age of film wasn’t all that long ago!
Anyways, ISO. The third leg of our exposure triangle, along with aperture and shutter speed. ISO comes from film, but still applies to your camera’s sensor. It is how sensitive the sensor (or film) is to light and how fine the grain is. So the lower the number, the less sensitive it is and the finer the grain is. That is why you use ISO 100 film for outdoors and a higher number (400, 800, etc) for darker photos.
So the million dollar question: How does ISO fit into the exposure triangle? ISO is the real team player here. It can sit back and just be in the background or it can really help you achieve the effect you are looking for in an image. For instance, say you are at your child’s indoor soccer game. You will need a fast shutter speed to catch the action, but what if you can’t get a large enough aperture (small number) to get the right exposure? That is where ISO comes to the rescue. Raise that baby up a bit and your day is saved! You may see a little more grain in the photo, or maybe not at all. But you will have a crisp, properly exposed photo now without having to slow down your shutter speed and risking a blurry photo. Congratulations, you are now the envy of all the other moms with blurry photos 😉
There are a couple things to keep in mind when choosing your ISO. I know, always something right? Well the good news is that you may easily be able to set your ISO to auto, even if you are shooting on manual mode in your camera! I figured this out on my camera totally by accident and it does come in handy, especially if you are shooting on a sunny/cloudy day where the light keeps changing. Just one less thing to think about while you are chasing after kids. One thing to be mindful though is the higher you go, the more grain you will have in your photo, even with digital. The amount of grain you see at different levels completely depends on your camera. So go out and experiment!
Hopefully these tips help you to try out manual mode on your camera 🙂 Please let me know if you have any other questions about this, I am always happy to answer them!