ND (Neutral Density) filters for drones usually come in two varieties. Your basic traditional ND filter and Polarizer ND filters.
Let’s consider each so that you can get a better idea of which type will be better for your needs.
But first, the simple reason for getting an ND filter is to get a good exposure while at the same time getting a nice cinematic look. I go into more detail in this ND Filters for Drones article.
When using an ND filter, the amount of light going to the sensor is reduced, but the color saturation should not be affected. Unless you buy poor quality filters.
Polarizers are useful because the block photons from passing through the filter based on the orientation / angle of the photons. By turning the polarizer, you effectively select which photons to accept and which ones to reject.
This allows us to block most of the photons that are being reflected off of surfaces such as water, glass and flat leaves. We then get pictures with less reflections. We also get a deeper blue sky and more saturated colors.
This can be useful for shooting around water when we want to see more details. But, it can be more limiting when it comes to color corrections.
Another thing to consider is setup time. With a regular ND filter, you put it on and go. With an ND/PL you need to adjust the polarizer ring until it is positioned how you want it against the location of the sun.
The best setting can change from shot to shot and so using a polarizer can be more time consuming.
So, it really comes down to personal preference. Do you want to see more details in and under the water or reduce glare on other items, try an ND/PL filter. Don’t care about glare or want more flexibility when color grading, go with a regular ND filter.
What do you think? How often do you use polarizers on your drone?