Part Seven – ISO settings

In this video we talk about the ISO setting to increase your camera sensors sensitivity

Transcript of Video

“The last of the 3 controls that make up the exposure triangle is the “ISO setting”.

And that’s basically the sensitivity of your camera’s sensor which captures the images that you take. The ISO comes from the old film days when you could select different sensitivities of film to use in your film camera. Well with modern day digital SLR cameras there’s no film necessary so ISO applies to the sensor which you are able to turn up and down. When you turn it up it is able to capture more light

As you can see in the illustration the settings run from 100 to 3200 some camera scale higher still to 6400 and above. As you move from left to right on the illustration the sensitivity of the sensor is increasing so that it’s able to capture more light it’s more sensitive to light. The negative side effect of turning the sensor up is the image picks up grain like noise which degrades the image quality.

For this reason It’s best to keep the ISO as low as possible at all times. Ideally keep it on the lowest setting for as long as possible only changing if you have to.

There are situations such as photographing in a darker shooting conditions where you have no other option than use a higher ISO setting to be able to get a photograph. And to be honest it’s better to get a photograph with some grain or noise in it than not get the photograph at all.

So in that circumstance if there’s nothing else you can do with the shutter and aperture and you’re force to turn the sensitivity up then it’s better to do that then get nothing.

Some people actually like the noise that comes with a higher ISO settings as it resembles film grain that used to be visible in the old film camera’s.
Play about with it and see how you feel about it yourself, if you like that kind of thing then that’s fine, but a general rule of thumb is keep it as low as you possibly can.

Of the 3 exposure settings, this is the one you want to be altering the least.

When I set the ISO I tend to set it so I know it will be ok for most of the shoot so I don’t have to keep changing it constantly. So if it’s a dark overcast day I will usually put it on 400 ISO from the start because I know that will give me the shutter and aperture settings I need most of the time, but that comes from experience and the more you practice the better you will be able to judge such situations.

Generally modern day cameras are not too bad up to about 800 ISO and noise becomes more visible from 1600 and over.

You should find that you’re altering the shutter and aperture much more often than the ISO when you’re setting your exposure.

Now the relationship that each of these ISO settings have to one another is similar to what we have experienced with the shutter and aperture in that as you move one setting to the next you’re either doubling or halving the amount of light to the previous setting.

So as you move from 100 to 200 ISO you are doubling the amount of light that the sensor is capturing, as you move from 200 to 400 you’re doubling again.

So as you move from left to right each setting is doubling the amount of light being captured to the previous setting.

And as you go in the opposite direction from 200 to100 you’re halving the amount of light being captured.

So again the setting is very similar to the aperture and shutter speed in that each setting doubles or halves the previous setting.

What we’ll do in the next video is look at how the 3 exposure controls that make up the exposure triangle the shutter, aperture and ISO interact with one another and how you can manipulate them to get different creative effects and to balance you’re exposure”.