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Photography 101: The Trifecta of Proper Exposure

What’s a Photograph?

Obviously, everyone knows what a photograph is but not everyone knows HOW to make a proper photograph nor the two main ingredients needed. And I’m not talking about aesthetics, the visual appeal, of a photograph; I’m only talking about the technical side.

To make a proper photograph there needs to be light and shadows. Sounds simple, but people don’t pay attention to that basic photography fact because the majority take pictures on their phones and phones are set on AUTOMATIC settings (nothing wring with that).

A photograph is, essentially, sensors in the camera, behind the lens, capturing light and the strength of it. Light will bounce off a subject and go onto the sensor. The more light that goes onto the sensor, the brighter the subject is captured. Subjects that aren’t lit up as much, shadowy areas, don’t have strong enough light going in the camera so the sensor can’t register it as clearly.

It’s easy to understand this in terms of our eyes. When the lights are off, you can’t see. If you turn on a candle, you can see the flame and objects that are lit up by the flame, but if you’re in a big room then you still can’t see much. Turn on a lamp, a stronger light source than the flame, and you can see more.

But in order to capture something properly, shadows are needed! Without shadows, a photograph can look washout or flat. Shadows help the subject look three-dimensional. It’s the balance of light and shadows that make a proper photograph.

The 3 Determining Factors

So how do we control how much light the sensor receives, the exposure? There are three determining factors that have to be taken into account when capturing a photograph: the ISO, the Aperture and the Shutter Speed. All cameras I’ve come across have the ability to control these three factors.

ISO

The ISO, which means International Organization of Standardization, controls the sensitivity of the sensor. Typically ISOs range from 200, 400, 600, 800…6400. The lower the ISO, the less sensitive the sensor is to light.

So if you’re taking photos when the sun is in full swing lighting up everything, the ISO needs to be lower or else the photograph will come out white. If you’re taking photos inside a room with a few lamps as the light source, the ISO needs to be higher so that the sensor can be more sensitive to light and try and pick up as much as it can.

But remember, the higher the ISO, the more noise, or grain, a photo has. This is why darker photos taken with your phone aren’t clear, the phone’s automatic setting bumps up its ISO to the max.

Aperture

The aperture, or f-stop, is the lens’s hole opening radius, if that makes sense. It’s the size of the hole in the lens where the light comes through. This size of the opening determines how much light is allowed to enter through to the sensor. In the camera settings the aperture is usually an number with an f in front of it. The scales of the f-stop goes: f/1.4, f/2, f/2.8, f/4, f/5.6, f/8. Rule of thumb: the bigger the number, the smaller the opening. Combining the aperture with the ISO can help achieve proper lighting for a photograph.

However, the size of the hole also adds another effect: the depth of field. The depth of field is the focus or blur level between the distance of the subject and its background. iPhones have created this effect under the Portrait mode in the camera app.

If the f-stop opening is smaller, the entire image, in terms of depth, is in focus. If the f-stop opening is larger then certain parts of the image will be in focus while the other is out-of-focus, again in terms of depth.

So let’s say you’re taking a picture of a person standing five feet in front of a sign and then a couple hundred feet in front of a mountain, in one picture. If the lens is at f/8 then the person, the sign and the mountain will be in in focus. If the aperture is at f/1.4 then the camera can focus on either the person and have the sign and the mountain out-of-focus, or focus on the sign and have the person and the mountain out-of-focus, OR focus on the mountain and have the person and the sign out-of-focus.

Shutter Speed

The shutter speed is the final determine factor and it’s probably the easiest to comprehend. Behind the aperture, in front of the sensor are shutters horizontal shutters that resembles blinds on a window. When the shutter release button is pushed, or for smart phones the button is touched on the screen, the shutters will open for a fraction of a second to all the light to hit the sensor.

The shutters are actual moving parts in the camera, they’re the iconic sound made when a photograph in taken. These shutters are always closed and only open when the shutter release button on pushed. Their purpose is to determine for how long the shutters remain open.

On a camera the settings for the shutter release button are usually preset to 1/2, 1/4, 1/8, 1/15…1/1000. These are fractions of a second, the length of time the light has to hit the sensor. If they’re open for too long such as 1/2 second then more light will enter compared to 1/1000.

So let’s go back to the scenario about taking a photo outside when the sun is out. Taking a photo with the shutter speed at 1/2 will be washed out because that’s too much time for the all that light to hit the sensor, 1/1000 might be more suitable. But if you’re indoors where the light isn’t as strong then 1/1000 might be too short of a time and perhaps 1/260 might be best.

But like the first two factors, the shutter speed also creates and effect. The longer the shutter speeds are open the more light is captured BUT movement can also be captured. The faster the shutter speed the less movement is captured; very fast shutter speeds can make someone running look frozen in the air.

In Conclusion

In terms of capturing a standard photograph, these three factors need to be taken into consideration. It’s always fun to play around with the settings of these and see how they work together to capture photographs. There’s nothing wrong with taking pictures on automatic mode but creativity comes from capturing a scene or portrait that looks a little different that normality.

In terms of taking a photograph with the proper exposure balance, this is all you need to know. I’ll post another article explaining colors.