Exposure Triangle : Aperture ,Shutter Speed and ISO

Exposure Triangle : Aperture ,Shutter Speed and ISO

So what exactly is an exposure triangle? It’s commonly identified with the  three important components of photography which affects the exposure of your photo consisting  aperture ,ISO and Shutter Speed. If you are a beginner in photography , this concept will help you to take another leap in your photography journey. Our camera captures the images through the control of light, thus a good understanding  of exposure triangle is needed to capture correct exposures or under and over exposed pictures  with the help of these three setting.




Aperture is a diameter of lens which opens all the time through which the light passes up-to the sensor. It controls the depth of field, which denotes the area of focus in photographs. It is basically measured by F stop. The larger the opening of the lens (say F2.8), the smaller the area of focus becomes. And smaller the opening of the lens (say F22) , larger the area of focus and deeper the depth of filed. You may get confused with the reverse order but in terms of aperture, F2.8 is larger compared to F 4 and similarly F4 is larger than F5.6 and so on. Read our article on 5 tips to better understand Depth of field.

shallow depth of field

a perfect example of shallow depth of field . This image has the sharp subject and a blur background. This is a image taken at a high f stop

Bride in manang with auto focus

This would be a perfect example of a deeper depth of field. A general rule of thumb is Landscape photographs are usually taken at lower F stop. Which will capture more result from the scene.

Shutter speed:

Shutter isn’t opened all the time. It is for the control of the duration of light inside the camera. Longer the opening of lens, the more light passes into the sensor and vice versa. It is correlated with aperture. Faster shutter speed is needed when you are to freeze fast movement objects such as a footballers, runners in the field, and a lot more action activities.

Below is the perfect example of a higher shutter speed. The photographer has used  higher shutter speed to freeze the action.

Fast shutter speed


Likewise,  when you need to capture photos at night, you need a long shutter speed. For more examples,   Silky smooth of waterfall, River,sea waves,etc. you need a long shutter speed. Read our killer tips for better long exposure photography


this is the long exposure panaroma of pokhara from sarrangkot.


ISO controls sensitivity to light.  Higher the number of ISO, the more it’s sensitive to light allowing to shoot in low light situations. Lower number of ISO, the less it’s sensitive to light allowing to shoot in bright sunny days. Higher the Number of ISO, the more we get noises in our photos and vice versa.So its up to the photography to choose an iso number that would make light enough sensitive to take a well exposed image but at the same time wont create high noise in the image. I remember a very good advice i found some where in internet , dont be afraid to play with the ISO. So when ever  i talk about ISO i encourage photographer to experiment with different number of ISO.



The three components Aperture , Shutter speed , ISO make up the exposure triangle in the photography. To get the correct exposure , the photographer has to play with the setting of these three elements. Once you get a good understanding of these three elements , you will be able to balance the exposure with balancing these three setting with each other.A very easy example would be , suppose i want to take a photography of a cyclist , who is in a certain good speed. If i choose the shutter speed to be 1/2000 second , and aperture to be 2.8 , and i want to have  shallow depth of field . But even the 2.8 f stop would not let enough light inside camera. Now i cant decrease the shutter speed since i want to freeze the action of the cyclist. So the option i will have , i have to increase the ISo . I hope i was able to make you understand the basic concept of the exposure triangle. Look at the exposure cheat sheet above. In case of any question , please feel free to comment or write directly to us.

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About author

Anup Ghimire
Anup Ghimire 60 posts

Anup ghimire is a self learned Photographer/Designer and recently graduated in multimedia technologies from London metropolitan university.Traveling is something he loves the most after photography. You can see some of his photos at his facebook photography page https://www.facebook.com/intomyviewfinder

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