This is the fun part.
Now you know the “primary” effects of shutter speed, ISO and aperture: To control the exposure in order to make a pleasing photograph. But as you undoubtedly know, there are other, more subtle effects that come into play with your choices for these settings. We’ll call these the “secondary” effects. That is where some of the art of photography comes in. The choice of the values for these three legs of the Exposure Triangle usually affects the way the final image looks.
For some photographs, the choice of shutter speed, aperture and ISO have very little impact on the final image, for example, the image of Wilson Hall, above. It might be argued that for most good photographs these days, these choices are not important. After all, there is a lot of great photography out there from an iPhone camera!
But in my view, a good photographer needs to understand and be able to manipulate these secondary effects to get photographs that stand out from this point-and-shoot crowd.
Let’s understand how and why.