A few people have asked me about the correlation between the actual Camera settings the F-Number on the camera and the actual available amount of light entering the camera or F-Stop, and how to know which F-Number to use to reduce the light by a certain amount of light.
So rather than try to write a description about the numbers I decide to draw up a chart.
How to use the Chart
The chart is pretty simple to understand, along the top are 3 columns, starting with Full Stop, 1/2 Stop then 1/3 Stop, reading down each column you see the camera F Numbers. The gap between the F Numbers is the amount of light you are reducing or increasing into the camera.
Lets say you want to reduce the light by 1 Full Stop of light, simply look at the first column titled Full Stops and switching the F-Number on your camera between these settings will decrease or increase the amount of light accordingly. Using the second column and switching between these F-Numbers will reduce light by 1/2 Stop and finally switching between the F-Numbers in the 3rd column will reduce light by 1/3 Stop.
I hope this all makes sense, any questions just let me know in the comments.
