Exposure Triangle: Aperture, part 2

In my last blog we talked about how the aperture is similar to the eyes pupil in that it regulates the amount of light that goes into our eyes. Our eyes do this automatically, and though our camera does a good job at doing auto functions 95% of the time we sometimes need to change the aperture to fit our shooting needs, or for some; to show off how awesome we are that we actually know what the little numbers mean on the side of our lenses, or if you’re not old on your display, we are talking about digital photography after all. That’s where knowing the dreaded f-stops come into play. When looking at the f-stop scale you see a series of numbers

Most begin to freak out instantly when they see the even more dreaded decimal points, I know, I know, what is this math? I didn’t sign on for this. The good thing is that the math has already been done for you, so quite being such a baby. Only thing is the math is screwy and the numbers seem backwards when lined up to the aperture size. f2.8 being a wide open aperture (really big opening) and f22 being a very small aperture (very small opening). I promise you the geniuses that do the calculations are correct, they just needed to make us photography guys look like we know more than we do. So you now know that the little numbers match up to the size aperture we need, f2.8 letting in a lot of light, and f22 letting in very little light into our camera. But I can’t stop there, if you are to gain a firm understanding I must confuse you more. As we descend the scale, saying if you go down a stop (from f22 to f16) you are doubling the amount of light you are letting into the camera. Where if you ascend the scale (f16 to f22) you are halving the amount of light, makes sense right? If I have a squash, and I double the amount of squashes I have, I now have two squashes. If I drop one of the squashes I now have only one squash (and a big mess) halving the amount of squashes I recently had. Like your eyes, To get the proper exposure you need to know how much light to let into the camera, This will hopefully become more clear when we bring the other two parts of the exposure triangle together Shutter Speed and ISO. Until then you now know that size really does matter, aperture size that is.