Camera fundamentals

This little post is for anyone new to photography and camera fundamentals. I will be covering the basic three fundamental functions of a camera. Every camera on the market uses Shutter speed, Aperture and ISO to control the amount of light recorded. Let’s dive a little deeper into each of these functions and look at the unique qualities these settings bring to your photograph.


Left image; Photo used a shutter speed of 1/15 of a second, which captured motion blur. Right image; Photo used a shutter speed of 1/2000 of a second, which freezes motion in the photo.

Shutter speed

Let’s start with the shutter also known as exposure time. There are many different types of shutter systems. Each camera uses one, be it a leaf shutter, focal plane shutter, Diaphragm shutter, electrical shutter or central shutter. All you need to know is the shutter controls the exposure time, in which the shutter opens for a chosen period exposing the light-sensitive material (film) or recording mechanism (sensor) to light, and then closes once that period of time is up, stopping the light reach the film or sensor.

The shutter speed controls the exposure time which effects motion capture. If you want to capture fast action use a quicker shutter speed 1/1000 to 1/8000 of a second will freeze motion. And if you want to capture motion or a blurring effect use a slower shutter speed 1/60 or longer. These are just examples, I highly recommend to experiment when it comes to shutter speed. A good idea for getting a sharp photo handheld, depending on how steady your hand is and the type of shutter your camera uses. But to stop camera movement don’t go below 1/250 to 1/60 when holding your camera.

The faster the shutter speed, the less blur will occur in the image. At the same time the less light you will let onto the film or sensor. If you choose a fast shutter speed at night, your most likely to get a darker image, compared to the same shutter speed in the day time. This is because of the amount of available light your letting hit the film or sensor. Think of it like filling a glass, the longer you keep the tap on the more water you’ll get in the glass. This is the same with opening the shutter, the longer the shutter is open the more light hits the sensor. There are ways to counteract this which we’ll cover next. but keep this in mind, the shutter speed controls the exposure time, meaning the amount of light your recording.


Left image; Aperture wide open at 1.4. Right image; Aperture stopped down to 16.


This mechanism is commonly a part of the lens. Aperture has two functions, controlling the amount of light that hits the film or sensor and it also controls the depth of field. Think of it this way, the more light you let in through the shutter the shallower the depth of field gets. The less light you let in the larger the depth of field gets. So if you want the background of your subject blurred out of focus, open up your aperture and let more light in. In contrast, if you want everything to be in focus, close down your aperture and let less light in.


Left image; Photo captured using aperture 1.4, creating a shallow depth of field. Right image; Photo captured using a aperture 16, creating a large depth of field.

Another confusing part of the aperture is the numbers, 0.95, 1.0, 1.2, 1.4, 1.8, 2.0 are all considered wide apertures. Meaning the aperture on the lens is wide open, letting as much light in through the lens as it’s capable of. This causes a shallow depth of field. The aperture numbers 8, 11, 16, 24 are considered closed or stopped down apertures. This is when the aperture blades come closer to gather, letting less light through the lens, and the result of that is a sharper image and also a larger depth of field meaning more of the foreground and background is in focus.

One thing to also take note of, is with some lenses the higher the aperture say 16, 18, 24 doesn’t always generate a sharp image, this is because of diffraction. basically, this means that the hole created but the aperture is so small that it ends up bending the light rays passing through it, adding a creamy effect to the image. A lot to take in here I know but lets move on.


Left image; Captured using ISO 3200. Right image; Captured using ISO 200.


ISO stands for International Organization for Standardization, also referred to by some cameras and films as ASA, which stands for American Standards Association. Confusing right?! But all you really need to know is these acronyms stand for the standard of how light sensitivity is measured. ISO is just the standard of sensitivity that film or sensor has. The lower the number the lower the sensitivity to light, and in contrast the higher the number the more sensitive your film or sensor is to light. So why do I also need to control this on top of the shutter speed and the aperture?

Let say you want to use a stopped down aperture so everything in your frame is in focus, plus you want to freeze motion, so you also choose a fast exposure time. Well in doing this you have chosen to let less light in by opening the shutter for a short period of time, and you have also chosen to stop down you aperture which intern lets very little light in through the lens. This would result in a dark image. To counteract all these decisions you have made, to get the desired photo you want. We need to increase the sensitivity of your film or sensor. This is where ISO comes in, choosing a hight ISO number will increase the film or sensors sensitivity, which increases the amount of light recorded. Thus balancing your aperture and shutter speed to get the correct exposure for your image.


So to recap Shutter speed controls the exposure time of light on the film or sensor. Aperture controls the depth of field and amount of light getting to the film or sensor. ISO controls the sensitivity of your film or sensor. And there you have it, the fundamentals of the camera.