• Aug 1, 2017
Understanding the concepts of ISO & Exposure

What is the most important thing for the photographers?
Of course the ‘light’.
All we care about is how well-lit or properly exposed our photos are, here is an in-depth guide to ISO and Exposure, with the basic difference and how to control them to create the best shots.
 

What is the difference between ISO and Exposure?

In digital cameras, to control the amount of light in the photos we have three settings ISO, shutter speed, and aperture. Together they are called the ‘Exposure Triangle’. Let us take on each of the components of the Exposure Triangle one by one and know how to use them in the best way possible.

1. ISO
ISO is a measure of the camera sensor’s sensitivity towards the light. ISO is measured in numbers ranges from 100 to 6400 and even higher in some cameras. The lower the number, the lower the sensitivity. Lower ISO is used where there is a good amount of light and we gradually move towards higher ISO in low light conditions. In some cases, we want grains too in the images. Grains at higher ISO are not always bad. Shoot up the ISO when you don’t want to use the flash and also in low light situations.


Lower ISO produces lesser noise and no grains.




To experiment with ISO switch to program mode. In program mode, you only need to choose the ISO and it will automatically adjust the shutter speed and aperture.


2.Shutter Speed

Shutter speed is the time for how long the light will be allowed to fall on the sensor or for how long the shutter remains open. Faster shutter speed allows lesser light and results in lower exposure and vice versa with the slower shutter speed.



To experiment with ISO switch to Program Mode. In program mode, you only need to choose the ISO and it will automatically adjust the shutter speed and aperture.

2.Shutter Speed

Shutter speed is the time for how long the light will be allowed to fall on the sensor or for how long the shutter remains open. Faster shutter speed give allows lesser light and results in lower exposure and vice versa with the slower shutter speed.


Slower shutter speed: Allowing light for longer duration creates great effects. This must be accompanied with proper aperture and ISO to balance the Exposure.



Lower shutter speed is used to properly expose the city nightlife.


Higher shutter speed is used to freeze the frame and take shots of an objectmoving at high speed. Switch to Shutter Priority Modeto learn more about shutter speed. It lets you select the shutter speed and ISO, the rest is taken care of.

3. Aperture

Aperture controls the amount of light passing through the lens. A wider aperture f/3.5 allows more light to fall on the sensor and results in higher exposure. A narrower aperture reduces the light falling on the sensor and results in underexposure. The aperture also controls the depth of field, which is completely a different topic. 

In outdoor shoots with good lighting conditions, go with narrow aperture to get a picture with balanced exposure. Whereas, in the indoors and portraits go with a wider aperture.


An outdoor shot with a narrow aperture to click a well exposed yet balanced shot.


To understand it better, switch to Aperture Priority Mode and observe how other values behave with a particular aperture setting.

Conclusion

ISO is a part of Exposure Triangle. In other words, ISO is the part of a big picture when it comes to taking control over the light in photography. The key difference is that ISO adjusts the sensitivity of camera sensor and for exposure settings, we adjust the aperture and shutter speed. Now, on your next photo expedition, observe that which settings you need to tweak in order to get the desired click.




1 Comments

sayan sen

1 year ago

thanks...