What is the best ISO to use?

What is ISO?

ISO is the sensitivity of your sensor to light. The ISO setting you use depends on the amount of light in the scene you are photographing. The more light you have to work with the lower you can set your ISO.

As settings go, ISO is one of the key camera menus you need to learn. ISO numbers typically range from 100 to 6400 in most newer cameras. A few cameras go down to 80 ISO and some go as high as 25,000+ ISO!

One of the biggest benefits of digital photography is that you can change your ISO from one photo to the next. Back in the film days, you would have to choose your film according to the ISO, and then all your photos would have to be taken at that same ISO. That made taking photos in various lighting conditions tricky.

Guidelines to choosing the best ISO setting

On a bright and sunny day there is a lot of light so you can use a lower ISO setting. On a cloudy day there is less light, so you must increase your ISO. Indoor photos have even less light and if you don’t want to use a flash, you can bump up the ISO to compensate for the low light.

  • 100 or 200 ISO for sunny and bright daylight
  • 400 ISO for cloudy days, or indoors for window light portraits
  • 800 ISO for indoors without a flash
  • 1600+ ISO for really low light situations – that school play your kid is in

The trade off to shooting in really low light situations

You won’t miss a low light shot again! But, there is a trade off. As ISO numbers go up, so does the noise in your photos. Here is the proof:

Look at the difference between 80 and 1600 ISO in these photos.


Notice how much smoother the 80 ISO photo looks. The 1600 ISO photo shows lots of noise. You can really notice it in the darker areas. (The camera I used in those photos was an older model Canon point and shoot.)

Why not just use Automatic ISO?

If you don’t understand the manual settings and you’re in a hurry, sure go ahead and use Auto ISO. But I recommend you keep an eye on the noise factor in your photos.

Like the video says, do some tests with your camera. Figure out your noise tolerance. If Auto ISO is taking you to high levels of noise, it might be best if you learn how to use the manual settings.

Smaller sensors = More noise (usually)

You will notice ISO noise more in smaller sensor cameras, like small point and shoots. A full frame dSLR camera hardly has any noise at high ISO levels. But my older small point and shoot gets unbearable noisy above 400 ISO. So for me, Auto ISO isn’t an option with my small camera.

My Lumix mirrorless cameras have low noise at higher ISO too, even though the sensors are smaller than the full frame dSLR sensors. So noise is not always a factor of the sensor size. It has to do with the sensor quality too!

Works for video too

A lot of you are shooting video now, and the same rules apply for video ISO settings. Whether you shoot video with your dSLR or a handy cam, you’ll need to keep your eye on the noise. The smaller the video camera sensor, the more noise you’ll get at high ISO. In my experience, camcorders are especially noisy in low light.

Every camera is different.

Make sure to test yours! I test out every new camera I buy, and sometimes I test them out before I buy them.

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