what is an iso in photography

What is an ISO in photography

Hello my wonderful readers, I hope everything is alright. In this article I will explain what is an ISO in photography and why is important to learn how to manipulate it to take quality images.

Whether you are taking pictures with your phone or with a digital camera, the ISO have its role to help you take viewable images even in dark situations. By increasing or decreasing ISO, you are able to make your images look brighter or darker, depending on the environment.

Now lets see what ISO is in photography and how affects your images when you don’t set it properly.

What is an ISO in photography?

Back in the days when photos where taken on a film, which you had to buy every time you wanted to take photos because they where limited to 24, 36 or 50 positions, they where called ASA (arithmetic) and DIN (logarithmic) film speeds.

Later in 1974, the International Organization for Standardization (ISO) decided to combine ASA and DIN film speeds into ISO standards. And from then on, ISO defines both arithmetic and logarithmic scales for sensitivity.

Vintage camera film
Vintage camera film with an ISO of 400, with 24 positions. Meaning that you could take 24 pictures with an ISO of 400.

ASA and DIN was referred to the sensitivity of the film (how sensitive the film was to the light). And as technology evolved, manufacturers created digital cameras with different sensor sizes, with the same purpose, and, to make it easy for you to maintain brightness levels within the camera.

To take high quality images, there is the so called exposure triangle, which is composed by aperture, shutter speed and ISO. These three settings are the dough of your images.

What is an ISO in photography
WClarke and Samsara, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons

ISO is included in the triangle but it’s not part of the exposure. A little confused? Yeah, I was too. ISO is there only to show you how bright or dark your image will look after processing. Most of the exposure is done by shutter speed and aperture.

As you increase the ISO, your image will come out more nosier, this is because it is intensified. The noise is already in the image, but, with lower number ISO’s our eyes cannot see it.

The recommendation is to stick with the lowest ISO, which is 100, and adjust shutter speed and aperture to let the light into the sensor. But, there will be situations when you have to increase ISO too. In macro photography you don’t need to increase it much, the max should be 800. But even in this case your images could end up with noise in some cases. Higher ISO numbers 3200 or 6400 or even higher, are used in astral or night photography to increase brightness on images.

ISO 3200
ISO 1600
ISO 100

As you can see in the images above, increased ISO intensifies noise and the images are not usable at all. On the other hand, the image at 100 ISO has sharpness and no visible noise. This is a quality image.

Of course there are editors like Photoshop and Lightroom where it has the option to reduce noise. But the image is already ruined, and by reducing noise, the image will come out too smooth and without sharpness. It’s ok if you want to leave it like that. But in macro photography it is more suitable for the images to be sharp.

How to set ISO on a digital camera

Changing ISO can vary from camera to camera, but the most used is the manual setting where you can adjust everything as you wish. I will show you from my Canon camera how to set ISO to give you an idea.

First of all, turn on your camera, then turn the dial to M for manual.

manual setting

Press the Q button or on the display (if you have camera with touch screen) or the ISO button to switch between ISO numbers.

You can also change ISO in the Av (Aperture Priority), Tv (Shutter Priority) or P (Program) settings.

How to set ISO on smart phones

Tap on the camera app on your phone and look for the A and M settings, A stands for Automatic and M for manual. On some smart phones you will find them in the settings menu.

Camera settings

Tap on A and then select Manual. Here you will have the option to change white balance, shutter, ISO, exposure and so on.

Smartphone camera

Bottom line

Keep in mind that ISO is there only to show you how bright the images will look after processing. Shutter speed and aperture brightens or darkens your images by capturing light into the sensor.

Most of the camera’s in our days have the Auto-ISO option which helps you a lot in low light spots. You can set a maximum ISO you want to use so your camera does not cross that limit. But, shutter speed will progressively increase if your camera will reach that limit, creating more motion blur.

If you have any questions please let me know in the comments section below, and I will be more than happy to help you out. Be safe and take care.

This post may contain affiliate links. I receive a small commission only when you make a purchase using my link. Read the full disclosure here.

Spread the love

Leave a Reply

Your email address will not be published. Required fields are marked *

Download icon icon by Icons8 KeyShot icon by Icons8 Open Book icon icon by Icons8 Info icon by Icons8
error: Content is protected !!