Reply to What Lens Filters Are Worth Having?

photofarmer posted a reply:

@LittleEgret and Richard Landry:



Another idea would be to get a linear polarizer which you can put in front of your circular polarizer. Rotating that filter will give you a wide range of ND filters. The only problem is that it won't be calibrated or repeatable. You could fix that by putting scratches on the ring of your filters so you could return to a specific setting.



PS: two circular polarizers won't work. You need one linear (on the outside, away from the sensor) and one circular (on the inside, nearer the sensor).