Take Better Pictures - Lesson 3

Hello again!

This is the third installment of digital photography lessons. More lessons, tips and a few opinions are on my site: imagemaven.com

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I am working my way through the most important settings on your digital camera. The previous lesson explained image quality. Now I am going to examine ISO.

Lesson 3 - ISO Sensitivity

Camera menu

The graphic above is here as a reminder for all the settings lessons.

ISO stands for International Standards Organization, but that doesn't really describe anything about it. ISO is a number value that describes how sensitive your camera sensor is to light.

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!

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.

When you double your ISO, for example from 100 to 200, you double the sensitivity of the sensor to light.

There is a big trade-off to using higher ISO though, and that is the increase in NOISE. See the Extra Tips section for an explanation and example of what noise looks like.

So which setting should you use?

Use the list above as a starting point. For best results always capture your images using the lowest ISO possible. This will reduce the amount of noise in your photos.

Your homework this week:

I suggest you do a noise test with your camera. Take photos of the same scene using all your ISO settings. When viewing your photos up really close on your computer, at some point, the noise is going to be really noticeable. Noise shows up mostly in the shadows (dark) areas of your photos.

That point will vary with each camera model, and your own tolerance to ISO will vary as well. You need to ask yourself, at what point does the noise really bug you? Whatever ISO that is, remember it for future reference, as any photos you take at that setting may not be acceptable quality in your eyes. Having said that, if your daughter is figure skating in a dimly lit arena and you need to capture the action, you may well have to use 1600+ ISO to get a decent shot. In that case, getting the photo is more important than the noise quality.

When I did this test, I had these results: On my point & shoot camera the threshold was 400 ISO. On my big professional camera that I use for client work, it was 1600 ISO.

This is due to a better, and also larger sensor of the professional grade camera.

Extra tips for this lesson»

»What does noise look like?

Noise looks a bit like film grain. You start to see the image break down into coloured specs and the photo also starts to lose detail. Below is a comparision betwen two photos taken with ISO 80 (top) and 1600 (bottom) with a Canon G9 compact camera:

ISO 80 sample photo

ISO 1600 Sample photo

The one taken with ISO 1600 really breaks apart in the transition area from black to orange.

»Noise Reduction

You can reduce some amount of noise in your camera by choosing a noise reduction setting. You should test it out first to see how the different settings affect your images.

Noise shows up mostly in the dark areas of your photos, as you'll see once you do your own tests. You can also reduce noise in post processing using the built in tools in Photoshop and Adobe Camera Raw.

If you reduce noise in your images too much during post processing, they will get softer looking. It's always best to try and shoot with as little noise as possible, and that is achieved by using a lower ISO.


Every new generation of cameras and sensors deals with noise better. An older camera model (4+ years is ancient in the digital world) will probably show more noise at the higher ISOs than one you buy today.

Next Lesson: White Balance

This lesson will show up in your mail box in a week.

In Between

Don't forget about your homework! The only way to really figure all this stuff out is to play with your camera.

Also, remember to check my website, ImageMaven.com for new blog posts. You can add comments to the posts as well. Leave your url and it becomes a great way to get some exposure for your own site too!

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Happy Shooting!