If you already shoot digital, you know how exposure works on a sensor: check the screen, watch the histogram, protect the highlights. Film plays by slightly different rules, and understanding them is the single biggest step towards photographes you are proud of.
The good news is that exposing film correctly is simpler than it sounds, especially with a modern film camera that does the metering for you. Here is how film exposure works, which film gives you the most room for error, and the habits that turn a hopeful roll into a reliable one.
Key takeaways
- Exposure is the amount of light that reaches the film, set by aperture, shutter speed and the film's sensitivity (ISO).
- Colour negative film is forgiving: it copes far better with too much light than too little, so when in doubt, give it more.
- Always set the camera to your film's ISO, then let the light meter and automatic exposure do the heavy lifting.
- For your first rolls, an ISO 400 colour negative film offers the widest margin for error in changing light.
What does exposure mean on film?
Exposure is simply how much light reaches the film. Three things control it: the aperture (how wide the lens opens), the shutter speed (how long it stays open) and the film's ISO (how sensitive it is to light).
Get the balance right and the negative holds detail in both the shadows and the highlights. Too little light and the image turns thin, muddy and grainy; too much and the brightest areas start to lose detail.
On a digital camera you can check the result instantly and try again. On film, the result waits until the roll is developed, which is exactly why getting exposure right at the moment of shooting matters so much.
Which film makes exposure easier?
Your choice of film sets how much margin for error you have. For learning exposure, three points matter:
Film speed (ISO)
ISO 100 to 200 films give fine grain but need plenty of light, so they suit bright, sunny days. ISO 400 is the all-rounder: it handles sun, cloud and shade, which makes it the most forgiving choice while you learn. ISO 800 helps in low light and indoors, with a little more visible grain.
Colour negative versus slide and black and white
Colour negative film has the widest latitude, so it forgives small exposure errors. Slide (reversal) film is far less tolerant and punishes mistakes, so it is best kept for later. Black and white negative film is also forgiving, but its tones take a little practice to read.
Match the film to the light you expect
Think about where you will shoot before you load. A bright beach holiday suits a slower film; a winter city break or evening streets suit ISO 400 or faster. Choosing the right speed for the light solves half of your exposure problems before you press the shutter.
Why film exposure is different from digital
This is the key idea for anyone coming from digital. A digital sensor clips highlights hard, so digital shooters learn to underexpose slightly to protect the bright areas.
Colour negative film works the other way round: it has a wide latitude, especially towards overexposure. A negative that received a little too much light usually still prints beautifully, while an underexposed negative loses shadow detail that no scan can bring back.
That is why film photographers often say "expose for the shadows". In practice, if you are unsure, lean towards more light rather than less.
How the PENTAX 17 helps you expose correctly
A reliable light meter and automatic exposure take most of the guesswork away, which is exactly what the PENTAX 17 is built to do. Set its ISO dial to the speed of the film you have loaded, and the built-in meter reads the scene while the automatic exposure sets the camera for you.
Simple shooting modes cover the situations that cause difficulties for beginners, including a slow shutter-speed mode for low-light conditions and a built-in flash for interiors and evening shots. If a scene misleads the exposure meter (such as with highly reflective backgrounds like snow or at the beach), you can use the exposure compensation dial to add more or less light with a single turn without having to go through any menus.
And because it shoots half-frame, about 72 frames per roll, every exposure lesson costs half as much as on a standard camera.
Tips for well-exposed negatives
A few habits make a big difference from your very first roll:
- Set the ISO before anything else. A wrong ISO setting throws off every frame on the roll. You’ll find the ISO value on every roll of film.
- Give it more light when unsure. With colour negative film, a touch of overexposure is far safer than underexposure.
- Watch backlit and bright scenes. Snow, beaches and a subject against a bright sky can fool the meter; add exposure with the compensation dial.
- Mind dark scenes too. A small subject against a large dark background may need a little less light to keep it from washing out.
- Keep the camera steady in low light. Slower shutter speeds show every movement, so brace yourself or use the flash.
- Note your settings. Jot down tricky situations and compare them with the developed roll; it is the fastest way to learn.
Reading your negatives: learning from each roll
Your developed roll is the best exposure teacher you have. Hold the negatives up to the light: a well-exposed colour negative looks dense but clear, with visible detail in the darkest parts of the scene.
Very thin, almost transparent frames were underexposed; very dense, dark frames received a lot of light but will usually still print well. Compare what you see with the notes you took, and within a roll or two you will start to predict the result before you press the shutter.
Once exposure clicks, film stops feeling like a gamble and starts feeling like a craft. It is a shift PENTAX explores in it's time for film, and you can see where the brand's return to analogue began in the film camera project.
