I would like to know what is the difference between ''normal'' ND filters and polarized ND/PL filters, in equal light conditions and place.
What advantages or disadvantages do ND/PL have over ND ?
I have seen that Freewell has in its catalog the option to buy the same filter as ND (Normal) or ND/PL (Polarized).
When using one or the other, is there any noticeable difference in capturing photos, for example?

Hello and good day Bullflier. Thank you for reaching out and for giving out these information. The ND/PL filters includes a Polarizer in the same filter, while the ND is just that a neutral density filter only. In addition, ND filters reduce the amount of light coming into the sensor, giving you more control of the camera's aperture, exposure time, and sensor sensitivity settings. Thank you.

Polarizers are a good addition to ND filters if you need to lessen the effects of reflections on certain surfaces (such as windows, water, ice etc.) For instance, if you are recording outside of a car and want to be able to properly record what's inside of the car, you'll want to minimize the reflections on the windows and that's where combined ND polarizers come in handy.