A&P iso?

Discussion in 'Lifestyle' started by Eric Happy Meal, Nov 12, 2004.

  1. Eric Happy Meal

    Eric Happy Meal New Member

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    so what exactley is the difference between the ISO's of film, and what type of pictures you should be taking with a certain iso, and if you use a different one how would it affect the picture?
     
  2. mojito

    mojito New Member

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    In film, the lower the iso the lower the size of the grain. With that, it is less sensitive to light, so there by needs more exposure to be properly exposed. A lower iso will produce a cleaner image if properly exposed. High iso films are used to steal exposure comensation. By going from 100 to 3200, a fine art photographer gains 5 stops of light to work with. Use the lowest iso that will allow you to take a proper photo unless you want really big grain and way more contrast. The higher the iso, the greater the contrast, especally in B&W.

    the iso list
    3,6,12,25,50,100,200,400,800,1600,3200,6400,
    4,8,16,32,64,125,250,500,1000,2000,4000,8000
    5,10,20,40,80,160,320,640,1250,2500,5000,10000

    The ones in bold are the common ones you'll see at most stores. You'll have to order or go to a specialty shop for others.
    64 is often used in studios with a tungsten balanced film, rather than day light balanced, as it takes longer exposures before reciprocity kicks in, where you need even more exposure to take a proper photo.

    That list should go in a rolumns and rows. For every three isos vertically changed (50 - 64 - 80 - 100), that is one full stop of light. For every 1 horizontal iso change (100-200 or 1600-3200) that is one full stop of light.

    Your aperatures are
    1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32, 45, 64, 90
    every horizontal move is one stop of light, where the amount of light doubles. So a aperature of 4, is twice as much light as 5.6

    Your shutter speeds are
    X > 1, 1/2, 1/4, 1/8. 1/15, 1/30, 1/60, 1/125, 1/250, 1/500, 1/1000 X > X

    Every horizontal move is one stop of light, again, doubling the amount of light.
    Notice how the shutter speeds are similar to the isos, thats not a coincidence

    Cliffs:
    You a higher iso when shooting in low light, available light, result will be more grain and higher contrast, but less need for light

    Use a lower iso when you want a cleaner image and theres lots of light, like a nice sunny day.
     
  3. ElDude

    ElDude Hiya!

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    On my little Casio Exilim pro600, 50 ISO along with 100 are really good, 200 is grainy and 400...well, I can't see anyone in their right mind using that setting (on this camera).
     
  4. mojito

    mojito New Member

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    Digital is different that film. It produces noise, which is not accebtible, where grain can be. Point and shoots, although the p600 is a great little cam, are more prone to noise than DSLRs with higher quality sensors. I can shoot at 1600 or 3200 and be fine as long as I use a noise reduction software program.
     
    Last edited: Nov 13, 2004
  5. ElDude

    ElDude Hiya!

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    Must be, I understand it :big grin:
     

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