ISO is one of three ways to control your exposure, and you should definitely know a little bit about it.

ISO is one of those expressions you may have heard about, but never really understood completely. When I started this blog, I made a promise to keep things simple, understandable and with examples. In this post I will not get into the most technical aspects of ISO, but rather walk you through what it does, and how to use it.

No matter what camera you use, you will need some sort of light source to get the photo. Have you ever noticed that taking a picture in dark conditions makes the photo look all grainy and ugly? A snapchat selfie in dim lights, look horrible compared to the one you take mid-day, right?

Your photo is made up by three core pillars.

To get the overview of the three – take a look at this post.

To explain ISO in the simplest way possible, we can compare ISO to how sensitive the sensor in your camera is to light. It makes it possible to produce a photo, even in dark environments. Out on a sunny day, when there is plenty of light, your camera won´t need to use much ISO. Often the ISO will be at the lowest setting, which usually is between ISO 5o to ISO 200, depending on the camera model. Once the light decreases, the camera will increase the ISO to compensate, and thereby properly expose the shot. So what´s the big deal? That sounds awesome, right? Letting the camera choose the ISO automatically for you, to get the best result?

You see – there are consequences.

With high ISO, comes a quite dramatic effect. At least at high ISO values. We call it grain, or noise. It looks like a thousand small dots, all over the image, often in weird colors.

High ISO

High ISO might look grainy and horrible

At high ISO values, the grain will be very distracting and at worst completely ruin the photo. What is high values, you ask? That really depends on the quality and age of the camera. Newer, expensive cameras will be able to handle extreme values, with little loss in image quality. Newer models may use ISO up to 12 800, or even 25 600 without problems. On the other hand, an entry level DSLR anno 2014 might not be able to go above ISO 1600 before the images begin to look like s***. Let´s have a look at some photos, with ISO 100, 400, 1600, 6400 and all the way up to 25 600, the maximum value my camera allows.

First we´ll have a look at the images in full size, and then we´ll zoom in a bit to really see what´s going on.

Let´s zoom

So as you can see, if we simply compare the first, ISO 100, to the last, ISO 25 600 – the difference is huge, capital H.

ISO 100

ISO 100 introduces very little grain


ISO 25600

ISO 25600 – This image is totally ruined. There are spots and speckles all around

So what to do, and how to avoid high ISO?

The main thing is to get out of auto-ISO in your camera settings. If you are not familiar with the three core pillars that makes for perfect exposure, you should also read “What is shutter speed?” and “What is aperture?”. If you can support the camera either with a tripod, a table or simply by leaning against something, you can often have a much slower shutter, which in turn allows you to lower the ISO to an appropriate value. I would recommend to stay below 3200 for most cameras, and below 6400 if you only gonna use the photos for Instagram, Facebook or other social medias. The reason is that they usually compress the images so hard, that the grain mostly disappears.

There are ways to reduce noise in post production using editing softwares. I´ll get back to that in a later post.

Allright – So I hope you got something out of this read, and that I´ll see you back here shortly. What do you struggle with when it comes to photography? I would love to hear your thoughts and comments in the comment section below.

Until next time – I wish you the best of days, and happy shooting 🙂 See you out there!

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