Film Format & Film Speed

1. Film Format & Film Speed By: Amit Chawla

2. Difference • Film Format refers to the size of the film and with it the quality of photograph that is taken with a particular type of film. • This should not be confused with film speed. • Film speed describes a film's threshold sensitivity to light. It is related to the size of the Grains in the film.

3. Film Formats • Films are available in various sizes and ratios ranging from • Large Format • Medium Format • Small / Standard Format

4. 4” x 5” 6 x 7 cm 6 x 6 cm 35 mm 16 mm 6 x 4.5 cm Various Film Formats

6. Why different formats? • Larger formats mean finer quality, bigger enlargements and also better camera movements. • Small formats mean smaller camera which are faster to use and also portable. Also smaller formats give a greater depth of field than pictures on larger formats (keeping lens and f-number constant) • Small cameras as well as small format films are cheaper than medium and large formats.

7. MOST COMMON FORMAT • 135 (ISO 1007) is a film format for still photography, also widely referred to as "35 mm". Introduced in its modern form in 1934 it quickly grew in popularity, surpassing 120 film by the late 1960s to become the most popular photographic film format.

8. Film speed describes a film's threshold sensitivity to light. The international standard for rating film speed is the ISO scale which combines both the ASA speed and the DIN speed in the format What is film speed ?

9. Grain size refers to the size of the silver crystals in the emulsion. The smaller the crystals, the finer the detail in the photo and the slower the film. The lower the number (e.g.. 100), The less sensitive to light your film is, the higher the number (ISO 3200), the more sensitive to light your film is. What does grain size do ?

10. 100 1600

11. Common film speeds include ISO 25, 50, 64, 100, 160, 200, 400, 800, 1600, & 3200. Consumer print films are usually in the ISO 25 to ISO 800 range ISO 25 film is very "slow", as it requires much more exposure for usable image than "fast" ISO 800 film. Films of ISO 800 and greater are thus better suited to low-light situations and action shots (where the short exposure time limits the total light received) Common film speeds

12. SLOW FILM finer grain and better color. Slow film resolves finer resolution than fast film. It requires longer exposure times, so you might need a tripod At some point, it becomes wasteful to use slow film if u don’t enlarge FAST FILM Not as fine Less resolution Short exposure . Good for motion and less light Shows same product at small enlargement DIFFERENCE

13. An example

14. EXTRA INFO • Film speed is related to the size of the grains of silver halide in the emulsion, since larger grains give film a greater sensitivity to light. • Fine-grain stock, such as portrait film, is "slow", meaning that the amount of light used to expose it must be high or the shutter must be open longer. • Fast films, used for shooting in poor light or for shooting fast motion, produce a grainier image. • Each grain of silver halide develops in an all-or-nothing way into dark silver or nothing.