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ISO – What does it Really Mean?

Ever wonder what the ‘word’ ISO actually stands for? Well look no further, because I have dug into it and hope I can shed some light (no pun intended) on it.

Photo by mephisto19

We all know that the ISO rating refers to film speed. ISO is actually somewhat of an acronym that stands for International Organization of Standardization (“ISO”:http://www.iso.org). This organization sets internationally recognized standards for many industries, and photography is one of those industries. There are several particular standards that reference the Determination of ISO Speed. I would love to elaborate more on the specifics of the standards, but that would require purchasing them;). There are other systems of referencing film speed, but for this article, the focus is on ISO as that is currently the most commonly used system.

So, now that we know what ISO stands for, let’s focus on the speed aspect of it. Speed, or velocity, refers to how quickly something can travel (time) over a certain distance. The velocity equation is:


where v = velocity, d = distance, and t = time.

Wikipedia tells us that “Film speed is the measure of a photographic film’s sensitivity to light…” (Film Speed). But how does that relate to velocity? In my mind, I would interpret film speed to mean the rate at which a given film can absorb light. Therefore, the higher speed (or more sensitive) films such as 800 or 1600, absorb light more quickly, and lower speed (or less sensitive) films such as 50, 100, 200, absorb light at a slower rate.

Now it’s time to simply enjoy some randomly selected photos from the international lomographic community shot on film of various speeds.

ISO 25

ISO 50

ISO 64

ISO 100

ISO 200

ISO 400

ISO 800

ISO 1600

written by mafiosa


  1. breakingmyself


    Might be my eyes, but it seems the higher the ISO, the more grain a photo has too?

    over 2 years ago · report as spam
  2. mafiosa


    yes @breakingmyself that is correct. The higher ISOs do have coarser silver grains, hence grainier (LOL - is that actually a word??) results. Thank you.

    over 2 years ago · report as spam
  3. breakingmyself


    @mafiosa If it wasn't a word, it is now!

    over 2 years ago · report as spam
  4. yomimmo1


    Good article!! thanks a lot for using my picture!!!!!!

    over 2 years ago · report as spam

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This is the original article written in: English. It is also available in: Italiano & Spanish.