Balancing Aperture Size, Shutter Speed, and ISO
Updated: Apr 2, 2020
In my previous posts, I talked about aperture, shutter speed, and ISO. Now we'll talk about balancing the three to achieve the correct exposure - the balance of brightness and darkness in a photo.
To start with, you may have noticed from the previous posts that aperture size, shutter speed and ISO each (and collectively) impact how bright or dark your photo looks by affecting how much light your camera receives, or how sensitive your sensor is to the light it receives.
Here is a table summarizing how aperture size, shutter speed, and ISO affect your photos, with their impact on exposure highlighted:
Now, imagine you need 100 units of light to produce a perfectly exposed photo - the perfect balance of brightness and darkness.
If any one of these elements is changed to reduce the amount of light that gets processed (i.e. less than 100 units of light), your photo will get darker. Too little light, and the photo becomes underexposed - too much detail is lost in the darkest parts, called the "shadows".
Conversely, if any element is changed to increase the amount of light being processed (more than 100 units of light), your photo will get brighter. Too bright, and the photo becomes overexposed - too much detail is lost in the brightest parts, called the "highlights".
Finally, if you want to maintain how bright your photo is while changing one of the elements, you can do so by using either or both of the remaining elements to compensate.
For example, I wanted to create a moody golden look to this photo, to show night creeping up on the city of Porto as the sun goes down. So I have exposed the photo so that it's a little bit on the dark side, but just bright enough to avoid losing detail in the shadows.
Ultimately, your goal is to strike a balance between lightness and darkness to achieve the right exposure....but what is the "right" exposure? There's no fixed answer to this. It all depends on what sort of photo you're trying to craft, as well as the lighting conditions, and perhaps most importantly, how the brightness or darkness of the photo makes you feel about it.
Please consider sharing your photos with the community by tagging #dharmaportraits on your Instagram photos - I'd love to see how you're using these tips to create beautiful photos.