Film ISO Discussion and Why it Matters
ISO is a concept that many find hard to comprehend, but it is essential knowledge for experienced photographers. ISO actually stands for International Standards Organization, and refers to the standardized industry scale for measuring sensitivity to light. In digital cameras, you’ll notice if you ramp up the ISO value, your shots get brighter, but it comes with a sacrifice in image quality that causes higher levels of grain. But what does ISO mean in film, and why is it even more important?
If you’ve ever bought a roll of film, you might’ve noticed that it was labeled with a certain number speed film, most commonly 100, 200, 400, 800, 1600, or 3200. The higher the ISO or film speed number, the less light your film will require to develop a clear shot; however there's a potential for more grain in your image. 400 film speed and higher are considered to be fast film, which will allow you to shoot in dim light or increase your shutter speed to capture fast moving action shots. Slower film speeds like 100 and 200 are better fit for bright scenes, or for using wider apertures to create a shallow depth of field and defocus the background or foreground of your shot. As you can imagine, the ISO level of your film has a profound impact on the style and quality of your final image. So choose wisely based on your desired subject matter and aesthetic, and prepare to fill up your new film rolls with some dope shots!