Analog Q&A: What Is Film Speed In Photography?

Photo by Jakob Owens on Unsplash

For digital photographers, learning how to shoot film can feel like you’re starting from scratch. With all of the elements that define film photography – you may have questions that need answers. To help you learn more about film, we present our first Analog Q&A. Answering the question:

“What is Film Speed in Photography?”

Let’s talk about what film speed is and how to choose the correct film for your images.

The Definition of Film Speed

film speed
Photo by Mitchell Hollander on Unsplash

Film speed is referred to the measure of a film’s sensitivity to light. It is marked on your film stock as a number such as 100, 200, 400, 600, 800 or 1600.

The lower the speed of the film, such as 100, means you need a longer exposure to light to create your image.

The inverse is true for higher speeds of film such as 1600, where the exposure time is less. Yet, with these types of film – you will notice that the images produced will have a more dense and distinct amount of grain.

The film speed is measured using ISO, a term digital photographers will be familiar with. In fact, the digital use of ISO was designed to replicate the speed of film.

ISO refers to the International Organization for Standardization. You may also notice the abbreviation “ASA” for film speed – such as on your medium format camera. ASA is the American Standard Association. And, both are suitable to use when describing film speed.

Which Film Should I Choose For My Photos?

film speed
Photo by Immo Wegmann on Unsplash

So, now that we know what film speed is – how do we choose the correct film for our photography?

Low Speed Film

Lower or slower speed films are either at the 100-200 ISO mark. Since, they require a long exposure time, you traditionally use this film when there is plenty of available light.

For example, you could shoot this speed of film on a sunny day. Plus, this film is perfect for retaining crisp, high quality detail.

When to use low speed film? 

Sunny days shooting outside landscape, travel, still life or portrait images.

Medium Speed Film

Medium speed film is at the 400 ISO mark. This is one of the most popular film speed options for a wide range of shooting conditions. While you should refrain from shooting it on super bright days, you can use medium speed film:

  • In the studio
  • During overcast conditions
  • Sunny days with less harsh lighting

When to use medium speed film?

Studio photoshoots, portraits and still life, and overcast, diffused outdoor conditions with soft light.

High Speed Film

The final category of film is high speed film. This is film that is measured at the 800 ISO and above mark.

This type of film is used when you have lower lighting situations or are capturing moving objects. We use this speed because the film is fast and takes less time to expose to create your image.

Yet, it is important to note that higher film speed means more grain and noise. So, avoid shooting this film in scenarios where you want to retain clear, quality detail.

When to use high speed film?

At nighttime, in low lighting situations, when photographing moving objects or at concerts.

So, as you can see, choosing the speed of your film is determined by your specific photographic situation. Whether we use ISO 100, 400 or 1600 – it is important to know how these levels of film will affect and determine the outcome of our film photographs.

Did this Q&A help you learn more about film photography?

If so, send us more of your film related questions on Instagram at @h_collective – we will choose a question at random to answer in next week’s Analog Q&A!