Quote Originally Posted by BetterSense View Post
Don't worry about drifting the thread. It's not a problem at all.
Just so you know what you need and get, I attached two files. The first shows the step tablets you need, and how to use them. This will allow you to measure the exposure difference from highlight to shadows needed for each filter. You also need a table to turn the exposure differences into ISO contrast. That's what the 2nd attachment is for.