A 35mm format, sometimes known simply as 35mm, refers to a common type of image sensor format used in film photography. The basic rule is that the higher the resolution, the larger the film. Smaller formats, such as 35mm, will be considerably grainier when printed, but this is a common and appreciated side effect of film photography. Larger formats, such as 70mm, are capable of recording finer details but can also be very noisy when exposed correctly.
The term "35mm" is commonly used even if the actual size of the film varies from 35 mm to 44 mm. Some cameras have built-in options for taking films of different sizes, while others require you to use separate lenses for different widths of shots.
Before the advent of digital photography, there were two main types of photographic film: small-format (X-ray) and large-format. Small-format film was typically about 36 x 24 mm; large-format, about 70 x 48 mm. These dimensions relate to the size of the negative film frame, not the size of the final print. For example, an 8x10 inch print comes from a frame that is 56 mm wide by 84 mm long.
With modern cameras, the maximum resolution available on medium format film (such as 120 or 220 rollfilm) is about 7 million pixels, while with traditional large-format film (such as 645 film) it's around 15 million pixels.
The 36x24mm film format or image sensor format used in photography is known as the 35mm format, or simply 35 mm. It features a 3:2 aspect ratio and a diagonal measurement of around 43 mm. The name comes from the focal length of the average human eye, which is approximately 36 mm.
When shooting with film cameras, it is important to understand how different settings affect what you see on film. For example, increasing shutter speed decreases image quality by reducing the amount of light that reaches the sensor. Decreasing shutter speed increases image quality by allowing more light into the camera. Both have their advantages for specific situations, but knowing how they affect photos will help you create great images no matter what kind of camera you use.
Shutter speed is the amount of time the camera's shutter stays open to let in light. Faster shutters let in more light, so you can use shorter exposure times without losing detail in moving subjects. Slower shutters are needed to avoid blurry photos due to movement of the subject or camera shake caused by hand-held shooting. A tripod is always recommended when taking photos with slower shutters than you can shoot handheld.
Film speeds are terms used to describe the sensitivity of film to light. There are two main types of film: fast and slow. Fast film is more sensitive to light and requires faster shutter speeds to get good results.
The designation 35 mm derives from the whole width of 135 film, the perforated cartridge film that served as the format's principal medium prior to the development of the full-frame DSLR. The size of a frame on film is also referred to as an image scale factor, or simply scale factor. Frames on 35 mm film are approximately 1/35th of an inch (0.0312 meters) wide.
A camera can capture images that cover only a small part of a single frame on film or electronic media. Such partial frames are called sub-frames or strips. A sub-frame that shows only a central portion of the original image is called a center-cut strip. One that shows only one corner of the frame is called a corner-cut strip.
Sub-frames were originally used by photojournalists to avoid having to shoot multiple exposures of the same scene. A photographer would shoot several different shots of the same subject at different angles using separate frames and then join them together in post-processing software. This is still done today for visual effect. However, interlacing provides its own set of problems that must be considered when editing images. For example, if a person moves between two frames during the interval between photos being taken, the result will be visible as a ghosting effect when viewing the combined image.
Film photography captures photographs using light-sensitive film in cameras; anytime the film is exposed to light, an impression is taken. The word "35mm" comes from the width of the film cassette that holds the roll of film. Film speed, or ISO, indicates the sensitivity of the film. Faster films can capture more images per roll, while slower films require more rolls to achieve the same result. A standard photographic lens will produce different views of the subject depending on how it is mounted on the camera body.
Film photography has many advantages over digital imaging: beautiful colors, large tonal range, ability to handle high dynamic range (HDR) photos, and more. It also has some disadvantages like cost, size, and weight. Digital cameras have replaced film cameras in most applications but they are still used by photographers who prefer the quality of film or who need to work with extremely low light conditions.
A film camera uses film that is loaded into the camera at the factory pre-cut into individual frames. Each frame is made up of two parts: one that is transparent when dry and one that is opaque. When the whole roll of film is exposed, the photographer removes it from the camera and processes it.