Richard Cooper --- Cooper investment recovery inc wrote:
If I set my digital camera to f/8 and meter the light and the meter
gived me a shutter of 1/250-------by increasing the shutter to 1/500
less light will be recorded and the image will be darker?
Is this correct and is there any summary reading of exposure settings
available?
Thanks
Richard Cooper
Yes Richard, your image will be darker. If you are using Photoshop
Elements 3 or CS, you will see in the histogram of levels that there are
fewer pixels in the light end.
Equivalent exposures can be thought of in a table:
Using your metered values, these are all the same exposures:
Aperture Shutter speed
f/2.8 1/2000
f/4 1/1000
f/5.6 1/500
f/8 1/250
f/11 1/125
f/16 1/60
f/22 1/30
I like to think of the changes in stops, and that is how I teach it.
1 stop is either a doubling of the light coming onto the sensor - or a
halving of it.
If the aperture INCREASES by 1 stop e.g. f/8 => f/5.6
then the shutter speed must DECREASE by 1 stop, e.g 1/250 => 1/500
You can quickly work out alternative sequences this way.
You can also think of ISO changes in the same way e.g.
If ISO changes from 100 to 200, the film is twice (100%) as fast so it
is 1 stop faster
THUS at 100 ISO
f/8 1/250
at 200 ISO becomes
f/11 1/250
f/8 1/500
f/5.6 1/1000
etc.
However, I'm sure someone else will have another way of expressing it!
Howard
