Film photography can feel intimidating at first. Many people look at the numbers on a camera and assume it's complicated or technical. In reality, the core principles are surprisingly simple. Cameras work in a way that is very similar to how our own eyes see the world.
When people talk about exposure in photography, they are really talking about the balance between three things: ISO, aperture and shutter speed. Once you understand how these three elements work together, film photography exposure becomes much easier to grasp.
ISO: Your ability to see in the dark
A helpful way to understand ISO is to think about your eyes adjusting to light.
Imagine walking from a bright sunny street into a dark room. At first you can barely see anything, but after a moment your eyes adjust and shapes begin to appear. Your eyes are essentially increasing their sensitivity to light.
ISO works in a similar way.
Low ISO values, such as ISO 100 or ISO 200, behave like vision in bright sunlight. Images are clean, sharp and full of detail, but they require plenty of light.
Higher ISO values, such as ISO 800 or ISO 1600, behave more like night vision. The film becomes more sensitive to light, allowing you to shoot in darker conditions, although the image may appear grainier.
In film photography, this choice is made when you select your film. One roll of film means one ISO setting for the entire roll. If you load ISO 100 film, you are essentially choosing “daylight vision”. ISO 400 is a flexible option for mixed lighting, while ISO 800 works well in low-light environments.
Understanding how ISO works in film photography is the first step toward mastering exposure.
Aperture: Your pupil
Aperture is very similar to the pupil of your eye.
On a bright day your pupil becomes small to limit the amount of light entering your eye. In photography, this would be a closed aperture such as f/16. Less light enters the lens, but more of the scene appears sharp and in focus.
In darker environments your pupil widens to allow more light in. This is like using a wide aperture such as f/2.8. The camera captures more light, but the depth of field becomes shallow, meaning only your subject may be in focus while the background becomes beautifully blurred.
Aperture therefore controls two things at once: the amount of light entering the camera and how much of the image appears sharp.
Shutter speed: The blink of an eye
Shutter speed can be imagined as blinking.
If you blink very quickly, you only see a frozen moment in time. In photography this is a fast shutter speed such as 1/500 of a second. It is perfect for freezing motion, like water splashing or someone jumping.
If you blink slowly, your eye gathers more visual information over time. In photography this would be a slower shutter speed such as 1/30 of a second or longer. Instead of freezing a single moment, motion becomes visible. Water may appear silky and moving car lights can stretch into glowing trails.
Shutter speed therefore determines how movement appears in your photograph.
How they work together
Your brain constantly balances how wide your pupils are and how quickly you blink so that you can see clearly in different environments. Cameras behave in exactly the same way.
For example, imagine stepping outside from a dark room into bright sunlight. Your pupils immediately become smaller to protect your eyes from the sudden brightness. In camera terms, this would be similar to moving from a wide aperture like f/2.8 to something much narrower such as f/16.
Your camera can make these adjustments automatically, or it can guide you with a built-in light meter that suggests the correct settings.
One classic guideline that many film photographers use outdoors is the Sunny 16 rule. This rule suggests that on a bright sunny day you can set your aperture to f/16 and your shutter speed to the inverse of your film’s ISO. For example, if you are shooting ISO 400 film, a shutter speed close to 1/400 or 1/500 will usually produce a good exposure.
The Sunny 16 rule is simple, reliable and surprisingly accurate for daylight photography.
Learning without overthinking it
The most important thing to remember is that photography is not about memorising numbers. It is about understanding the relationship between light and your camera.
A great starting point for beginners is ISO 400 film because it is versatile and forgiving in many lighting conditions. As you shoot more rolls, the settings will start to feel intuitive and natural.
Many photographers also use a light meter app on their phone to help suggest settings while learning. Over time you may find that you rely on it less and less as your instinct for exposure develops.
Mistakes are also part of the process. Some of the most iconic film photographs were technically imperfect, yet those imperfections gave the images character and atmosphere. Film, especially black-and-white film, is surprisingly forgiving when exposure is slightly off.
The best way to learn
The best way to understand film photography exposure explained in simple terms is to simply start shooting. Load a roll of film, experiment with different lighting conditions and observe how your images change.
You do not need to master every number immediately. Once you understand the basic idea behind ISO, aperture and shutter speed, the rest will begin to fall into place.
Film rewards curiosity and experimentation. Trust your eyes and your instincts.
And if all of that still feels like too much, there is always another option. You can always pick up a point-and-shoot camera, load a roll of film and simply enjoy the moment.
