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film speed, and difference in price?


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#1 mary allison

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Posted 28 December 2006 - 02:50 PM

Two topics for one forum:

What is the difference between 500T and 200T, or the difference between "fast' and "slow" film?

and as long as I have your attention, I logged onto filmemporium.com and saw prices for film - the kodak 35mm filmstocks were $0.57 a foot, while Fuji was $0.44 a foot. Does that sound accurate - am I missing something. It seems obvious to go with Fuji.

thx
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#2 Kevin Masuda

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Posted 28 December 2006 - 03:03 PM

Two topics for one forum:

What is the difference between 500T and 200T, or the difference between "fast' and "slow" film?

and as long as I have your attention, I logged onto filmemporium.com and saw prices for film - the kodak 35mm filmstocks were $0.57 a foot, while Fuji was $0.44 a foot. Does that sound accurate - am I missing something. It seems obvious to go with Fuji.

thx


Fuji is usually cheaper than Kodak stock so it is accurate. The difference between 500T and 200T is it's sensitivity to light. 200T needs a longer exposure time so thus is why it's slower and the 500T is faster because it's exposure time is shorter. There are other differences between them but right now I can't think of all of them, someone else here could better explain them.

Kev
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#3 Patrick Cooper

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Posted 31 December 2006 - 04:53 AM

As Kevin stated, faster films are more sensitive to light. Slower films are less sensitive to light. Films with low 'speeds' or ASA ratings - eg 64, 50, 25 etc are classified as slow films. 100asa would be a medium speed film, and films with ratings of 200asa and higher would be classified as fast films. Both 200T and 500T are fast films though the 500T is faster than 200T - in other words, the 500T is more sensitive to light, so it doesn't need as much light for a correct exposure. In still photography, you would use faster shutter speeds or smaller aperture settings with fast film to compensate for this increased sensitivity. In cinematography, the shutter speed is fixed the majority of the time so you would usually close the aperture here. Slow speed films are less sensitive to light so they require more light to get an acceptable exposure. In still photography, this means using slower shutter speeds or larger aperture openings. In cinematography, most of the time, you would be using larger aperture openings.

Slow and fast films have different visual characteristics. Technically, slower speed films offer the very best image quality as they have a finer grain structure and usually quite strong, vibrant colours. Faster films have a coarser grain structure so grain will be a little bit more visible. Fast films are also often lower in contrast compared to slow films. Fast films, because of their greater sensitivity to light, can also be used effectively in low light conditions. You will also get more depth of field when using fast film for general shooting because you will be forced to use smaller apertures.
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#4 David Mullen ASC

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Posted 31 December 2006 - 12:53 PM

It's important to note that doubling or halving the ASA/ISO/EI is the equivalent of opening or closing down by one f-stop.

So the practical difference between 200T and 500T is 1 1/3 of an f-stop -- in other words, in the same light level, you might be at f/2.8 on 200T or f/4 and a third on 500T.
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