If you want to learn photography and take great pictures, you need to first learn the basics about film speed. In this article, you'll learn the basics of film speed and how you can use it to your advantage.
Cameras have lots of little knobs,
dials and meters. If you look long enough on a camera, you can find more ways to adjust your photographs than you can count, and for most of us, more than we can process all at once. But did you know that one of the most critical decisions you can make when preparing to shoot happens before you even load your film?
The speed of your film is one of the unchangeable qualities of a picture. There are plenty of ways to toy with aperture, exposure, and focus. However, once film is in a camera, there is absolutely no way to change the way that film reacts to light. In every photograph you ever shoot with real film, you are adapting to the film speed. Film doesn't automatically change to suit your needs, so it's important to choose the right film before you start taking pictures.
What is ISO?
Film speed measures how sensitive your film is to light. Low film speeds indicate that the film is less sensitive, and will require a longer exposure; high speeds are very sensitive and require shorter exposures. The speed of a film is commonly known as its ISO. Any film you buy will have its ISO marked on the box, and common speeds are 400, 800, and 1000, with 400 being the closest to the “standard."
The ISO of your film affects every aspect of the way your camera works. Your light sensor (if you have one) has to be set correctly for the film you’re using, your aperture will be more or less limited depending, and your shutter speed will likely have to decrease or increase to accommodate the film. Even digital cameras have a simulated (and adjustable) film speed that they base their calculations on.
Selecting the Right Speed
The ISO of your film decides what you are capable of photographing, and how. Because high speed film needs less time to expose (ISO 800 or higher is a good general rule), you can take images with much higher shutter speeds than with slower film. The end result here will be crystal clear action; fast film is wonderful for shooting sports or anything that moves quickly. When you see a photograph of a basketball player suspended in midair, you can bet that image was shot on high-speed film. With a slower ISO, the player in the picture would likely be a big blur. Faster film also needs less light and can be super helpful in situations where a flash isn't appropriate indoors.
Lower speed film captures more detail because it has more time to absorb light. It is important to keep the words “detail” and “blurry” separate here – more “detail” in a photograph can be thought of in a similar way to more “detail” on a high definition television – more of what was originally there will be visible in the photograph. The longer film can “see” a scene, the better the scene will be represented. Lower speed films are great for images like portraits where you want to show great depth of field.
Film Speed Experiments
To get a good handle on how ISO works and what it does to your images, here are a couple of things to try out the next time you’re planning a shooting day:
• Get rid of your flash (if you have one) and take some fast film into a low light environment
• Swing by a local high school, college, or little league game and try shooting (with permission) two rolls of film – one very slow (ISO 100) and one very fast (ISO 1000) – then have a look at how different the images turned out.
Film speed is one of those great things to play with when you’re pretty comfortable with your camera and you’re looking for new ways to challenge your perceptions. Each speed has strengths and weaknesses, and it’s up to you to decide which one works for you. Shoot on, photographers
