Discussion in 'Photography Beginners' Forum' started by rockstar, Oct 15, 2006.
What are EV steps? It says my D50 can do increments of EV steps in 1/3 or 1/2.
EV stands for Exposure Value. Or length of time the shutter will stay open. There is a set increment of steps to shutter speed. Those steps are:
...1/4, 1/8, 1/15, 1/30, 1/60, 1/125.... roughly each step is a half of the other or double depending what direction your going. Since these set increments were developed cameras have come out with the ability to have even more steps in between those above.
So if you were to set your camera to EV 1/3. The camera would allow 2 more shutter speeds between the ones above. So between 1/30 and 1/60 you could select 1/40 or 1/50.
Ah. gotcha. Thanks!
That is only part of it. The EV allows you to force the camera to under or over expose a picture. Say you are shooting on aperture priority and you decide your picture is to brigh, well you adjust the EV so its -.5 or so and take another shot. The camera will have increased the shutter speed so that less light gets in and you'll have a picture that is slightly under-exposed. on the same hand, if you are shooting in shutter priority mode and need to over-expose a shot, cranking it to +1.0 will open the aperture to allow more light in. It's just a way to shoot full manual, without shooting full manual.
Exposure value is more than just shutter speed...it's a combination of shutter speed, aperture and sensitivity of the recording medium (sensor or film). So if you change any of those three things, without changing the others...you would be changing the EV value.
Typically we express these values in terms of 'stops'...and would say something like "give it one more stop"
A 'stop' is a doubling or halving of the exposure. In terms of aperture...F8 to F11 is one stop. The size of the aperture at F8 is twice as big as at F11. In terms of shutter speed...1/30 is one stop more light than 1/60.
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