## View Poll Results: choose the correct formula

Voters
6. You may not vote on this poll
• GN2 = GN1*(ISO2/ISO1)

2 33.33%
• GN2 = SQUARE ROOT OF GN1*(ISO2/ISO1)

3 50.00%
• GN2 = GN1*(SQUARE ROOT OF ISO2/ISO1)

1 16.67%

# Thread: Quitz of the day ( 4 )

1. ## Quitz of the day ( 4 )

If the guide number for an ISO 100 film is 84, the guide number for an ISO 800 film would be ??

2. Eh, your formulas all very complicated lah. I can tell you the answer and it doesn't involve more than simple multiplication. No division, brackets, curly brackets, squares, square roots, cubes, cube roots, etc...

3. yah so cheem, guesstimate can already:

84 x 1.4 x 1.4 x 1.4 = 230.

4. what are you guys talking about ? what is a guide number?

5. If the guide number for an ISO 100 film is 84, the guide number for an ISO 800 film would be ??

answer is GN2 = GN1*(SQUARE ROOT OF ISO2/ISO1)

:

800/100 = 8

square root of 8 = 2.83

84*2.828 = 238

GN2=200.

the iso 800 guide number will be 238.

6. geeks. wonder if knowing this kinda info will help you guys score with babes.

7. must give complicated quiz mah, else time passes very slow.

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