Exposure Triangle: Shutter Speed

To look at shutter speed more effectively, I’m going to split the two words up and describe each on its own.

Shutter

If the pupil of your eye is like the aperture of your camera, and regulates the amount of light we need for proper exposure, than the shutter is like your eyelid. Not only does it keep our eyes moist, clean, and free of bug splatter it also regulates the amount of time light stays in our eyes. Have you ever tried sleeping with your eyes open? Probably haven’t had much success with that have you? If you close your eyelid you take away the light and when you open them again you allow the light to enter. It’s kind of like when we have tried to take a picture with the lenses cap still on (and yes, I said we) not really possible right? You need that light to get into the camera somehow, but just like that creepy relative that shows up to your home at awkward times of the day without being invited, knowing how long it should stay is another matter.

Speed

Sometime in our lives; we have either stolen, driven, or have had the honor of being a passenger in a vehicle during one or both. And as we travel down the road ignoring the black and white signs with insignificant numbers blurring past, we have had our head banging session interrupted by the blue and red lights flashing behind us, causing us to look down and realize to late that 55mph in a children at play zone probably wasn’t a good idea. If we look at speed as we do in the car, we have three important little letters MPH that means miles per hour. Let's take a math quiz to explain this further, If you are traveling at 60MPH how long will it take you to travel 60 miles? put the pencil down, and stop the frantic scribbling, three sheets of paper is enough. One hour right? Because there is 60 minutes in an hour, and if we are traveling at 60 miles per hour, we are driving a mile every minute. Now if word problems weren’t enough I’m going to hit you with fractions, because in photography we deal with fractions of speed. So, we know that there is 60 minutes in an hour, so one minute is 1/60 of an hour, and there is 60 seconds in a minute, making one second 1/60 of a minute, so how many parts are in a second? 60? 200? 2000? We know that a second is pretty fast already but to get proper exposure we have to go even faster sometimes. If I haven’t utterly confused you already, let’s look at an inch on a ruler.

Think of the inch as 1 second, if we go to 1/2 we are increasing the speed by 1/2 a second. If we go to 1/8, we are increasing the speed even more, and if we go to 1/16 we increase the speed even faster. So if you were able to divide the inch into 2000 lines allowing us to see 1/2000th of that second it would be extremely fast. The same is true with our cameras, 1/60th of a second is much slower that 1/2000th of a second.

Shutter speed also affects our images when it comes to freezing action or causing blur in our photographs, I’ll explain that later. In this lesson we are dealing with exposure and light so I'll continue with that. Simply put, If it is dark (little light) we need to keep the light in our camera longer to expose the image (lower shutter speeds, sometimes even whole seconds if it’s really dark). And if there is a lot of light, we need to get rid of the light quicker, as to not over expose our images (high shutter speeds).not only do we need to regulate the amount of light with the aperture; we also need to regulate the time the light sticks around with the shutter speed. Next we will discuss the ISO which regulates how sensitive our camera is to the light, wouldn’t want to hurt our cameras feelings now do we?

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.

Exposure Triangle: Aperture, part 1

The first part of our exsposure triangle is the apeture, If we think of our cameras aperture as the pupil of our eyes we can easily understand its function.

First question is what does our pupil do? It regulates the amount of light that is allowed into our eye.

Here’s an example, we have all gone to the movies at one point and no matter how hard we have tried we have one time or another arrived late, right before the trailers have started and right after the lights have been brought down to a scary black void; and as we stumble into the dark theater carrying our 40oz soda, extra-large popcorn, and those cheesy nachos that taste weird but beckons us back every time we are at the snack counter, we stop at the bottom of the stairs squinting our eyes, trying desperately to make out our family or friends who like crazed maniacs have been waving their arms franticly in the air trying to get your attention. While standing their trying not to drop all our goodies, something begins to happen. We begin to see the many faces start to emerge from the darkness, and we can finally ascend the stairs and bust our kneecaps trying to get to our seat. This becomes possible because our pupil dilates, growing larger and allowing more light in to give our site the proper exposure, allowing us to see. The opposite happens as we leave the theater. You walk into the sunlight after watching your movie and what happens? You are instantly blinded by the big fiery ball of death that makes you feel like your eyeballs are melting. But as you are on your hands and knees screaming for someone to help you, your pupils contract to let in less light, allowing you to see again so you can stand up, dust yourself off and awkwardly continue to your car blaming your outburst on the cheesy nachos that now are clinging to your arteries for dear life.

so like your eyes, our cameras also need the amount of light allowed into it to be regulated in order to give us a proper exposure. If we don’t, we end up with over exposed images or just white photos (to much light) or under exposed images or black photos (not enough light). So how do we do this? by setting our F-Stops, oh yeah another word just thrown in for good measure, I though you said this was about aperture? well it is and your aperture is your F-stops, we just need a set of numbers to set our cameras to and confuse you more that’s all. Photographers are sadistic like that.

Next: part 2, The dreaded F-stop