Written By:  Rachel @ Inscribed Photography 

Okay, one more post about the exposure triangle and then I’ll stop talking about it. Sound good?

We’ve talked about aperture and shutter speed already, so now we’re moving on to ISO. My first question about ISO was, “What the heck does ISO stand for?” The answer? Nothing that really makes sense. ISO stands for the International Organization for Standardization (I know, I know… they mixed up the letters). Back in the day you would purchase film with different ISO settings: 100, 200, 400, etc. Now, in the digital age of photography, you can change your ISO setting with a couple of clicks.

The ISO setting tells your camera how sensitive it needs to be to light. A low number represents a low sensitivity and a high number represents a high sensitivity.


So typically if you were shooting outside in bright daylight you (or your camera, if your ISO is set to Auto) would choose a low number, like 100. Since there is so much light available, your camera doesn’t need to be very sensitive to it. Here’s an example.


Originally my ISO was set to 400. When I looked at the picture after I had taken it, I saw that it was much too bright.


I changed my ISO setting from 400 to 200 and the results were much better.

Here’s another example of a picture that was too bright originally.


Sam changed the ISO from 600 to 200 and got this result:

When you change the ISO, you are basically telling your camera how much light is available around you. During wedding ceremonies (or really any time I’m shooting indoors) I have my camera on a very high ISO setting. Let’s look at an example.

This picture was taken at 1600 ISO. That’s a pretty high setting and the picture is still really dark. But let’s look at what else happens when your camera is using a high ISO.

Do you see all of the speckles and fuzziness? That’s called ‘noise’ and it’s caused by high ISO settings. So when you’re choosing an ISO setting keep in mind that the higher the number, the more noise you’ll have in your picture.

All cameras have an ISO setting, and most cameras will allow you to adjust the setting. On point-and-shoot cameras, look for it in your camera’s menu. It will probably be set to Auto by default but it may give you the option of choosing your own ISO numbers as well.

We’ve been talking a lot about exposure these past few posts. Remember that all three of the ‘points’ of the exposure triangle work together. If you change your aperture to get a different depth-of-field, you will probably have to adjust either your shutter speed or your ISO to maintain a good exposure.


So let’s recap a little:

  • The higher your ISO setting, the higher your camera’s sensitivity to light – usually resulting in a brighter picture but more noise.
  • If there is a lot of light around you, you probably need a lower ISO setting.
  • ISO works with aperture and shutter speed to determine the exposure of your picture.

I hope this little series has helped you understand some of your camera’s settings! As always, please let me know if you have any questions!

Rachel Gnagy

Rachel Gnagy is a wife, mother, photographer, coffee lover, and book nerd. She and her husband, Samuel, have four precious children, two boys and two girls. Rachel is a work-from-home-mom, running a small photography and graphic design business. She has been writing for Her View From Home since 2012 and loves the opportunity to communicate with other women. http://www.inscribedphotography.com/ https://www.facebook.com/InscribedPhotography