Understanding camera ISO

digital camera iso


Just for a recap, do you remember the three key elements that are the core of photography and work together with each other in every photo to create an “exposure?”

Yes, these are ISO, Shutter-Speed and Aperture which are commonly remembered through the exposure triangle. So as you all know it is paramount for every photographer to completely understand the workings of these three components, how they interact with each other, and how they impact the exposure in order to become a proficient photographer.

That is why today we are going to provide you with an in-depth explanation of one of these elements. The ISO. This element has so far become the most vital component of digital photography and is used most by the photographers.

Camera ISO

We have chosen ISO because it plays a very important role in the exposure triangle so here are some tips and tricks to use ISO in a creative manner, so that you can technically create a proper exposure.


At first, ISO was a term used in film photography days to define a film’s sensitivity to light. It was used to make film photography look less grainy, but today the term has evolved and stepped into the world of digital cameras but the concepts remain same.

What really is ISO?

ISO or ASA refers to the sensitivity of the camera’s sensor to light. There is a direct correlation between Exposure and ISO – the lower the ISO number the lower will be the exposure as the camera’s sensor will be less sensitive to light and higher the number, the exposure will be more as the camera’s sensor will be highly sensitive to light.

So basically this means that if you want less grainy and clear pictures then use a lower ISO but if you want to add an artistic effect to your pictures by adding a little noise then raise your ISO.

The link between ISO and shutter speed

Secondly, there is a deep connection between shutter-speed and ISO as well. This is because if the ISO number is high and the sensor is more sensitive to light you can pair it with fast the shutter-speed to get a proper exposure.

iso camera

So if you are worried about getting blurry photos, then just check that your shutter-speed and ISO settings complement each other as explained in this article and your images will come out tack sharp.

Some examples:

Here in the first situation, you are shooting in the middle of the day which means it is most likely that you will have plenty of daylight. So, in this case, you will have to ensure that your ISO is as low as possible. This will result in the cleanest image which will not only be noise free but will also have the most dynamic range and depth of color.

In the second situation, you want to emulate an older look by making the photograph feel as it was taken on film having a grainy appeal. So for this, you should make use of high ISO numbers as this will add a little noise which will produce an artistic effect.

You can add grain in post-processing but you won’t get the exact same look so it is better to experiment with ISO.

When to consider changing ISO

ISO is usually changed when one of the other components of the exposure triangle is altered. So in order to maintain the exposure you have to change the ISO in the opposite direction. In most cases, ISO is changed in relation to shutter speed to provide more light.

Aperture vs ISO

If your shutter speed is slow but you want a better exposure, you have a choice between raising ISO and widening the aperture to get a better image. So in the above situation, the photographer has to create a subjective balance and for that, he/she has to make a decision to select either wider apertures or higher ISO.

digital camera iso

This tradeoff will likely depend on the subject being photographed and the circumstances as they are the most important factors which impact your image and lead to the choice of selecting one route or the other.

For example, if you are conducting a family portrait session in the shade, and your shutter speed is only 1/50th on the 50 f1.4 lens it is pushing the limits and will easily blur the subjects if they slightly move or even if you don’t hold the camera still enough.

Thus, to get more light in the shade you have to make the trade-off to either lower the aperture to widen the opening for more light to pass or raise the ISO to make the camera more sensitive to light.

These both will enhance exposure but only one can be chosen at the expense of other. Whichever you chose there will be some pitfalls because if you widen the aperture it will result in less depth of field, and if you raise the ISO it will lead to more grain and noise.

In order to help you better understanding the camera ISO, I would invite you to watch Tony & Chelsea Northrup youtube video ”ISO: The Ultimate Guide”. It is quite illuminating the ways of ISO in camera settings:

Some situations where high ISO is required:

• Wedding Ceremonies that take place in Churches where flash is not allowed

• Concerts and events that have lots of movement

• When capturing Birds in flight with long telephoto lenses as usually, they require extra fast shutter-speeds

• When capturing Sports actions that have fast movements and require telephoto lenses with fast shutter speeds

• When making use of “zoom kit-lens” as they don’t have wide apertures so for the compensation you have to make use of higher ISO numbers.


No matter what you do, if you cannot grasp the concept of ISO and are not able to use it properly then your photographs will always lack the professional outlook. This is because in today’s camera ISO has become a very vital component and the best of the best photographers use it to make their results look extraordinary.

Remember anybody can click a photograph, but to add magic to it you have to master the settings. It is the choice of settings that differentiate a breathtaking photograph from a normal photograph.

So, in order to make the right choice you have to understand the digital photography settings and amongst the basic components is ISO which needs to be mastered as it can take you a long way.

It might look a bit too much to grasp right now, but once you start practicing it will become easy as practice makes you perfect. So now it’s your turn to go out and start applying what you have learned and do wonders to your photography skills, by adding a touch of ISO to it!

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Author: condruzmf

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