Saturday, August 7, 2010


So, we’re now unto our last component of the exposure triangle: APERTURE. I saved this for last because this is the easiest of the three (in my opinion). So, without further ado, let’s discuss Aperture!

Aperture is the only component of the exposure triangle that is dependent on the lens. The ISO and shutter speed is in your camera. Your aperture is located in your lens. So basically, your aperture depends on the lens that is currently mounted on your camera.

So what is Aperture? Aperture is a mechanism that can be likened to the iris in your eyes. It opens and closes to increase or decrease the light that passes through to the sensor. The larger the opening, the more light it allows to pass through. The smaller the opening, the less light it allows to past through. It’s that simple!

Aperture is expressed as F –STOPSRemember: the lower the F stop, the larger the opening. The higher the F stop, the smaller the opening. It’s a bit confusing at first but I’m sure you’ll get it in time. Normal zoom lens doesn’t have fixed apertures. For example, in the kit lens, in 18mm the aperture is at 3.5 while in 55mm, the aperture is at 5.6. That’s why it is 3.5-5.6. There are lenses that have fixed apertures even if you change focal lengths. They are a bit expensive because they are for pros. They are used for events where there is a very low ambient light. (btw, ambient light is another name for available light. Why use “ambient light” if we could just say “available light”? Because it sounds more professional, that’s why.) They use it because it allows more light into the camera. If you allow more light in, then it will fill up the sensor fast with light so it can help you reduce the shutter speed. 

“Wait what?!”

So to make it easier, let’s imagine these:

LIGHT = big, fatty, thick, juicy burger
SENSOR = lazy, fat, infinitely hungry kid who is in denial of his size so he sees himself as a kid who has big bones rather than a glutton who can eat as much as a hungry crocodile
SHUTTER SPEED = time it takes for the aforementioned kid to eat the burger
APERTURE = drooling mouth of the “el fatso” kid

Let’s imagine the ginormous fat kid with a big, fatty, thick, juicy burger. Unfortunately, his mouth is too small. (Actually, he got so fat, everything got bigger except for his mouth. Talk about irony!) If he eats that big burger using that small mouth (as if he has a choice), it will take him around 45mins to finish it all. But if he has a bigger mouth, then he could finish it probably within 10 minutes. So as you can see, aperture has a direct effect on shutter speed! But I am getting way ahead of myself. It’s actually supposed to be discussed on our next lesson, how each component interacts with each other. So I’ll explain it in detail then.

Now before I tell you the “special characteristics" of Aperture, I’ll explain first two new terms: Depth of field and Bokeh.

Depth of field or DOF is basically the part where the image is at it’s sharpest. It refers to what is in focus. There are two kinds: Deep and Shallow. Deep depth of field is where everything is in focus. Shallow depth of field is where only a small portion of an image is in focus. Everybody loves shallow depth of field mainly because it separates the subject from the background or foreground. I think you'll understand it better if you see it on a series of pictures. So here are the examples:

As you can see, everything is in focus.

In this shot, if you look closely, the background (laptop keyboard) is blurred. That's because the cellphone is the subject in the photo. But if the subject is the laptop keyboard, you can focus on the laptop and make the foreground (cellphone) blurred like in the photo below:

Bokeh is the quality of the blurred part of a photo. It is very subjective. Most people think of Bokeh as the little colored dots in the background of a photo. But technically, anything blurred is called bokeh. Bokeh came from the Japanese term “boke’ which means blur. The spelling was later changed to help the people pronounce it properly. It is pronounced with the “bo” as in boulder and the “keh” is pronounced as kettle.

Here's a picture with a "creamy" bokeh:

Anyway, the special characteristic of aperture is this: the bigger the aperture, the more Shallow the Depth of field and the better the Bokeh. It’s that simple. So if you like those kinds of pictures where the background or the foreground is blurred, then you just use the biggest aperture that your lens has (again, the bigger the aperture, the lower the number).

Easy right? Next time, I’ll teach you how each of the components of the exposure triangle interacts with each other. You'll be saying goodbye to auto in no time! =)