EV values

[PlaneGuy]

A question for you knowledgable folks,

From my reading on the web, an EV value is for a specific ISO (100 if not
specified). However, my reading on other sites indicates that there is a
direct relationship (conversion) between EV and lux values. If this is true,
then the ISO must be a fixed value.

So, what is the actual meaning of EV. And does anyone have some
authoritative references on the web?

[Wiz]

PlaneGuy wrote:
> A question for you knowledgable folks,
>
> From my reading on the web, an EV value is for a specific ISO (100 if not
> specified). However, my reading on other sites indicates that there is a
> direct relationship (conversion) between EV and lux values. If this is true,
> then the ISO must be a fixed value.
>
> So, what is the actual meaning of EV. And does anyone have some
> authoritative references on the web?
>
>


A combination of f stop and shutter speed is an exposure value.

eg f8 at 1/125th is the same as f5.6 @1/250th this is an exposure
value of EV13



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[Wiz]

http://www.ledtronics.com/pages/tech4.htm

PlaneGuy wrote:

> A question for you knowledgable folks,
>
> From my reading on the web, an EV value is for a specific ISO (100 if not
> specified). However, my reading on other sites indicates that there is a
> direct relationship (conversion) between EV and lux values. If this is true,
> then the ISO must be a fixed value.
>
> So, what is the actual meaning of EV. And does anyone have some
> authoritative references on the web?
>
Oh and lux this may help :)

http://www.ledtronics.com/pages/tech4.htm



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