Film Speeds
All films, whether traditional or digital, have a corresponding speed rating. You can see this number called ASA, which stands for American Standards Association and may also be called ISO, which is the same number but is represented by the International Standard Association. This number is known as film speed. Film speeds represent a film’s sensitivity to light. The higher the number the more sensitive it is to light. Usually, less light is required to take a well-exposed image. The film speed also indicates the detail from the negative. There are different film speeds ranging from 25, 100, 200, 100, 1600 and even 3200.
Film speeds correspond to the time needed to take the picture, also known as shutter speed. Many professional photographers prefer lower ASA film speeds since it would usually take a longer shutter speed thus producing crisper pictures. Low film speeds, which hit 100 and below are known as fine grain films because the grains that make up the film are so small. Low speed films are usually ideal for outdoor sunny conditions, but may also be used indoors as long as your subject does not move too much and your camera is on a tripod, otherwise your pictures can become blurry. Photo enlargements from a fine grain film also appear good as well. Since lower film speeds need more light for exposure, they normally tend to separate contrast differences well and appear to have more contrast compared to other films. Lower film speeds are perfect for nature and scenic photography.
On the other hand, those with an ASA film speed of 200 and up are classified as fast film speeds. This type of film has a larger grain size and requires lesser light when recording an image. Printing photos from a fast speed film may have visible grains to it. Taking pictures with higher film speeds such as a 1000 film speed usually takes a shorter period of time. Many sports photographers and photojournalist use higher film speeds because they can ‘freeze frame’ moving subjects even in poor lighting conditions. However, they are most costly compared to lower film speeds and often leave your pictures grainy, in which enlargement of photos is not advisable since it will only enhance graininess of the image.
Simply put, the lower the number of the film speed, the more light is needed. The higher the number, the more light is required.
25 to 200 film speeds work best for still life, portrait, studio and other conditions wherein lighting is controlled. A complete lighting set up is needed to use the 200-film speed effectively. However, this may not be ideal for indoor family shots even if the camera is equipped with a flash. 200-film speed provides good color saturation and details and is ideal for outdoor sunny conditions.
400-film speed is known as an all-purpose film. This is also great for use outdoors although you may still be using your camera mounted flash in room lighting conditions. The 400-film speed gives you more flexibility in darker conditions and when capturing moving subjects. 800 to 1200 film speeds are especially made for taking fast moving subjects to freeze frame in practically all types of lighting conditions. The 1600 film speed is designed for higher speed shots.
In addition, ultra high film speeds have an ASA or ISO film speed of 3200 and requires very little amount of light to get an exposure. Ultra high film speed films are great for indoor photography. However, this type of film may have problems in terms of contrast. Many photojournalists and action photographers use this type of specialty film as well.