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1. ## Sunny 16 rule

what math equation do you use to determine the number of stops darker in doors than outdoors if a photograph is properly exposed photograph is taken indoors at ISO 800, f/2.8, and at 1/50 of a second ?
Im trying to calculate sunny 16 rule and compare how much darker it is.
For instance if I do Sunny 16 rule on one picture
and use f2.8 ISO 640 and 1/50 second, is this how to calculate this?
f/16 is 5 times darker. And for reference I pick out 100, 1/1000.
5 times lighter for iso. and 4 times lighter for shutter. So it would be 4 times lighter?
I don't see 1/50 second for shutter speed though.
I have seen these 2 questions posted on another forum. It appeared to me that the question is a homework question rather something the poster really wanted to know. It it is the case how would the instructor taught the students to get answer to these kind of question. I know there are many ways to come up with the right answer but someone who teaches a photography class and put such a question in the homework how would that person teaches the students to solve the problem?

2. Wow, that equation could give an art major a migraine.

3. It is called a light meter used correctly not a mathematical equation.

4. I guess they meant to stipulate that it's sunny-16 conditions outside, which means they're basically asking "how many stops difference between f/2.8 at 1/50 and f/16 at 1/800?" Seems like a reasonable exercise for someone learning to do calculations in stops, though it's not expressed in the clearest way (which could be down to the asker or the original exercise).

-NT

5. +1, The human eyes and the brain are very poor instruments to evaluate light because they react too quickly and imperceptibly to changes of light intensity for us to notice them.

6. I like to use a lightmeter in those cases.

Jeff

7. I think the OP's posted the questions rather poorly but really the question has nothing to do with determining correct exposure. It only asks the difference in stops for 2 camera settings.

In the first post is really asking between f/16@1/100@ISO100 and f/2.8@1/50@ISO800 how many stops difference are there?
In the second post is really asking between f/16@1/100@ISO100 and f/2.8@1/50@ISO640 how many stops different?

That's all has nothing to do with getting proper exposure and that is why I think it's an academic question and not something the OP wanted to know.

8. Chan,

For a photography class that first question is truly a mess. An art teacher is asking a complicated math question.

The teacher doesn't ask for the answer/the difference; he/she is asking for the equation. Essentially asking them to write the equation to find the logarithmic difference between two settings.

9. 9 stops darker

10. Originally Posted by Chan Tran
I think the OP's posted the questions rather poorly but really the question has nothing to do with determining correct exposure. It only asks the difference in stops for 2 camera settings.

In the first post is really asking between f/16@1/100@ISO100 and f/2.8@1/50@ISO800 how many stops difference are there?
In the second post is really asking between f/16@1/100@ISO100 and f/2.8@1/50@ISO640 how many stops different?

That's all has nothing to do with getting proper exposure and that is why I think it's an academic question and not something the OP wanted to know.

the way it was worded was difficult to understand
but the end answer isn't very difficult to figure out ... i think ?

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