Understanding EV on a spot meter

[christopher valkenburg]

Hi folks,

 

Please forgive my noob question but I am learning about exposure. I understand the zone system and how to place areas on zones. I know there are zones 0-9. What I don't understand is, when looking at my spot meter, I have EV, or exposure value, increments. There doesn't seem to be a limit to the number of EV values and I can't understand how EV and zone values correlate or how to use them.

 

Please could you shed some light on this?

 

Thanks!

[Adrian Sierkowski]

Personally; I don't use EV. I don't see a point to really. I just need to get the F stop number for what I'm looking at given a certain ISO/Fps/Shutter Angle, which I like to define myself instead of have it algorithmically designated. I'd say EV is better for stills where you can/do change the shutter speed often to get an exposure.. but even then, I like doing it on my own so I can control the motion blur ect.

 

But this is a pretty good explanation of it

 

http://en.wikipedia..../Exposure_value

 

 

Basically; each EV is a stop; or a Zone. So once you figure out where your middle grey is in EV (let's say it's EV 10, then EV5 would be -5 stops, and EV15 woudl be +5)... if that makes sense.. But again, for me, I just stick with F top numbers.

[Chris Millar]

There is no limit to EV values as there is no limit to light (at least for the purposes of this discussion).

 

They are log₂ transformed values referenced to some value I'm not too sure of but I think something to do with a standard 100asa exposures and so on- anyhoo, you are correct in thinking they scale similarly to the zone system does but where you've gone awry is perhaps not recognising that the zone system has a limit on zones due to the very limits of film based media.

 

Light - which is to say 'un-sensed' light - has no relative limit in that regard.

 

Sure, your light meter senses the light like film does, but think of it having much more range than your film ever would.