For the past few weeks, we have been honing our technical photography skills. This week, we are going to go back to one of the basics in photography, ISO.

ISO goes back to film days and film speed. You would need different speeds of film depending on your lighting situations. ISO on your digital camera works the same way. Simpy put, ISO is the level of sensitivity of your camera to the available light. The lower the ISO number, the less sensitive it is to the light. The higher ISO number increases the sensitivity of your camera.

Most cameras have ISO settings such as 100, 200, 400, and 800. Depending on the model of your camera, you may have many more ISO options. Mine goes up to an ISO of 25,600!

So what does it all mean?


iso in photography

Week 31: July 27- August 2

ISO comes in handy when working with tricky lighting conditions. On a normal, sunny day, you probably won’t even have to change your ISO. An ISO of 100 or 200 works fine. There’s plenty of light so you don’t need a faster speed. If you are working on an overcast day, you may need to bump it up to 400.

Night time is when changing your ISO really comes in handy! By bumping your ISO, you don’t have to compromise your aperture or shutter speed. However, using a larger ISO may mean that your image will be grainy.

If you are shooting indoors without a flash, you will want to raise your ISO as well. If you don’t, you will end up with what is called “ghosting” and your image will not be sharp. “Ghosting” is when your subject is moving and they become blurry.

When in doubt, go with a lower ISO! You will end up with a better quality image. It’s easier to fix an underexposed image with post-processing than an overexposed image.

Here is a great comparison picture that I took in my living room one night to give you an idea how ISO works. All other settings are the same {f/ 2.8, SS 1/15 sec}.

iso example

The best two are ISO 200 and 400. If I didn’t want to do any post-processing, I would probably choose ISO 400 and call it a day. If any post-processing needed to be done, choosing the underexposed ISO 200 would be the one to use. By choosing the underexposed image, I don’t have to worry about blowing any channels and losing details when editing.

Where do I change my ISO?

This may vary on camera models. On most cameras, you will find your ISO setting in the Menu or Info section of your camera. Consult your manual if you are unsure of how to change your ISO. Remember, if you are shooting in an Auto modes, your camera with default to an Auto ISO.

I will admit that there are many times that I find myself frustrated in certain circumstances, such as low lighting. For whatever reason, I forget about my raising my ISO. I am used to photographing outdoors where the light is abundant. But, when I do head on over to my ISO menu and give it a little bump, I am surprised at the difference that going up level or two will do.

This week, your challenge is to play around with ISO. Take a series of pictures and change your ISO between shots. See for yourself how changing your ISO affects the lighting in your image. Make sure you share your photographs on Facebook!