Setting the correct exposure is one of the most fundamental of photography. With the inbuilt light meters in our camera’s, this becomes a piece of cake as we no longer need to work by the Sunny 16 or any other gothic rule. However over dependence on these inbuilt meters have meant most of the amateur photographers not able to count exposure mentally in terms of stops.
This ability to increase or decrease the exposure by stops comes in handy when one is trying his/her hand at really long exposures. Once you put a dense enough Neutral Density(ND) filter, you will need to count back in stops so as to determine the correct exposure. Depending on the density of your ND filter, this may demand to count back up-to 10 or more stops. Now if you’re sound of your knowledge about the aperture & shutter-speed scale, then you’ll breeze through. Else you might go for the trial & error method. However, the trial & error method would take sometime before you figure out the correct exposure. Instead, use ‘Exposure Calculator‘.
Exposure Calculator is a nifty android application which allows one to calculate exposure for long exposures. One needs to simply input the current correct exposure settings(indicated by your camera’s inbuilt meter) in the top part of the application after which you input the density of your ND filter in stops & you’ve your new exposure automatically calculated for you at the bottom. Makes sure you input the correct settings in the first place else your exposure will be skewed.
That’s it! Now if maths was not your favourite subject in high school, simply use the ‘Exposure Calculator’ & give all the worries of your calculation to your maths teacher. :)