Photography 101

Taking a photo on a smartphone may seem easy, but that’s because smartphones take care of many complicated things so you just need to press the button.

In this post, I’d like to talk about some basics of photography so without the help of smartphones, you can still get some nice pictures.

First things first, let’s talk about the ‘brightness’ of a photo, which we call ‘exposure’. If a photo is too dark, we call it ‘underexposed’, on the opposite, we call it ‘overexposed’. So what determines the exposure of a photo?

How much light you have of course. But in many situations, we can’t control the light source, but we can adjust our cameras to get the exposure we need.

Three things affect your exposure: aperture, shutter speed, and ISO.

Aperture is a hole-like mechanism in the lens that controls how much light will come through the lens. A smaller aperture means less light and vice versa. We describe aperture in f-numbers, something like f/1.4 or f/2. For a 50mm focal length lens, if its f-number is f/2, it means the hole for the light comes in is 50/2 = 25mm wide. Therefore, a smaller number actually means a bigger aperture. And every time the f-number is multiplied by the square root of 2 or roughly 1.4, the brightness is halved because only half the light can come in. For example, f/1 is two times brighter than f/1.4.

Shutter speed means how long your shutter opens, the longer the shutter opens, the more light hits the sensor so your image will look brighter. The shutter is also used to control movement, a fast shutter can freeze movement while a slower shutter can cause motion blur.

ISO, aka sensitivity, measures how sensitive your sensor is to the light. No matter you’re shooting with a film or digital camera, the higher the ISO is, the more noise your image will have.

These three things are in a triangle, so if one is changed, another has to be changed as well to maintain the same exposure. For example, in the same environment, a photo shot with f/1, 1/100 s, ISO 100 has the same exposure as a photo shot with f/2, 1/25 s, ISO 100. So there can be thousands of different combinations of these three values? Yes, but we need to think about how these values will also affect things other than exposure.

Aperture also affects depth of field, or how much things are in focus in your photo. A bigger aperture results in a shallower depth of field which is good for portrait photos when you want to blur those backgrounds. A smaller aperture, however, makes more things in focus so it’s good for things like landscapes. Choose your aperture accordingly based on your topic.

Shutter speed, as we’ve talked about, affects movement. If you’re shooting sports or wildlife, you definitely want a fast shutter speed. A slower shutter speed is useful when you want to smooth a waterfall for example. One thing to keep in mind is that when you use a slower shutter speed, your handshake will likely ruin the photo. That’s why we need a tripod to stabilize your camera.

ISO will affect your image quality, so unless the former two things are limiting, don’t crank your ISO up.

So there you have it, you’ve learned how to take a photo with the correct exposure if your camera doesn’t get the job done for you.

Since autofocus is so advanced these days, I think I’ll just skip this part as beginners can rely on the autofocus without any concerns.

The last thing I’d like to address is composition, but I’ll not go too deep into this topic as this is a 101 lesson.

Composition is a term to describe how you arrange your subjects in your photo. Naturally, we’d like to put our subject in the center of the frame and that’s totally fine. It’s just that sometimes it can be quite boring to look at, so there’re plenty of ways to composite your photos, like the famous rule of thirds.

Now you know how to correct your exposure, control the depth of field and movement, you also have the concept of composition in your mind. Give them a try and see if you can take some different pictures.