There are three things that determine your exposure: film speed, aperture and shutter speed. The speed of film, also known as ISO, dictates how much light your film needs to capture an adequate photo. Aperture controls how much light comes through the lens, and shutter speed controls how much of that light hits the film. These three things work together to produce your image.
In this blog post, we’ll be discussing film speed.
So, what is it?
Film speed is the sensitivity of the film. This ‘speed’ is determined by an ISO number, always found on your box of film. The ISO indicates how sensitive the film is to light, and lets your camera or light metre know what settings are needed to achieve a good exposure.
Low ISO numbers mean low light sensitivity. They require a lot of light to expose correctly. Whereas high ISO numbers mean high light sensitivity. They require less light for exposure. We recommend shooting with a low ISO to give the best photo quality, and a smaller amount of noise (what we like to call ‘grain’). This noise reduces the detail of an image by making the photo appear grainy and uneven.
Our general rule of thumb is: the lower the film speed, the higher the grain. The higher the film speed, the thicker the grain.
Films classed as ‘low-speed’ range from ISO 20-200. These films work best when you have lots of daylight available. Fujicolour C200 will give you a relatively fine grain, and help you capture fine details.
‘High-speed’ films range from ISO 400-3200. These films allow for more flexibility on overcast days and in low-light situations. Kodak Ultramax 400 will give you reasonably fine grain and still retain detail. Films with an ISO of 400-800 are great to use when shooting with flash indoors, and ISO 800-1600 is best suited to event photography and concerts where only low-light is available.
Experimenting with different film speeds is a great way to establish your own photography style. Trial new film types, shoot in unique lighting and have fun!