Slow film
A film having an emulsion with low sensitivity to light. Typically films having an ISO or 50 or less.
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Slow film
Film which has a limited sensitivity. Such films have low ISO speeds (e.g. 25 or 50 ISO).
(see Fast film, Film speed & ISO)
Slow lens
A lens with a small maximum aperture. (i.e. f8)
(see Aperture & Fast lens) ...
SLOW FILM - Film with relatively low sensitivity to light - typically having a film speed in or lower than the ISO 50 range.
SLOW LENS -A lens with a relatively narrow maximum aperture -ƒ/8, for example.
2. Use slow film or ISO setting. The idea is to allow fluid motion into your photos, which you'll achieve if you can shoot at slow shutter speeds.
Finer grained slow films are able to resolve more detail than faster, coarse grained films. Grain in itself is not something to be feared.
A slow film can be used successfully with a light source that has relatively high intensity, such as an electronic flash unit.
The problem is this: shoot with slow film or large format for maximum sharpness, shoot at apertures that provide adequate depth of field, this leaves a shutter speed that often falls into 1/15 sec. or longer.
Magazines were beginning to use color but the slow film speeds generally precluded its use for news stories. A few newspapers experimented with color, usually on the front or back page of the first section, but that was it.
Generally speaking, slow film (film which does not react rapidly to light) has finer grain than fast film (film which reacts rapidly to light) - see the section below on film speed. Enlarging a picture will also enlarge the grain.
Slow film has fine grain (and hence high definition), high contrast but low latitude. (Latitude is the amount by which a film can be over or underexposed and still produce a reasonable image).
Turns out he had used very slow film along with a long lens that opened no wider than f/4.5. The combination was death - it required long exposures that resulted in camera shake and blurred motion. Why did he use such a slow film, we asked?
It is common for fast film to have larger grain size and poorer rendering of colours (or grey scale) than slow film.
In addition, photographers often use a slow film speed or low ISO setting on a digital sensor to minimize grain (or digital noise) and increase exposure tolerance, as evaluating exposure is often tricky.
Acutance is a measurement of a film's ability to record edge sharpness, particularly between differing tonal areas. Slow films do this better than fast films, producing more appprent sharpness in the image.
(ISO stands for International Standard Organization and is the same as the older term ASA--American Standard Association.) The two films you mention, Fujichrome Velvia (ISO 50) and Fujichrome Provia (ISO 100), are both slow films.
Film speed is also related to the granularity of the resulting photograph. Portrait photographers and those looking for more detailed pictures tend to use "slow film" (film with slower film speeds) that require more light and decreased shutter speeds.
However, low ISO settings only work when your shutter speed is fast enough to stop the action of the subject. So whenever possible use slow film or the lowest ISO setting on your film or digital camera.
The term pronounced by the individual letters: I--S--O, not as if it were the word "ayso" The early term was ASA, which stood for American Standards Organization" Slow film have an ISO rating of 100 and less, while fast films are 400 and higher.
On a side note, most pinhole photographers use slow films like ISO 200, ISO 100 or even slower. The longer your exposure, the more forgiving the process will be. The photo below took close to 20 minutes to expose in a dark theatre: ...
Slow film is acceptable for indoor shots with flash, and optimal outdoors for non-moving subjects such as landscapes. Using a slower shutter speed will allow the film to expose longer, capturing richer colors and greater depth.
 See also: Slow, Film, Light, Photograph, Speed
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