Are physical filters for your cameras worth it in a world where almost any look can be replicated (usually) with ease in post?
Joking aside, the real answer depends on what you need and when you need it. Having a filter for your lens in the field can help you greatly if you need to turn around your video quickly. Meeting deadlines are a challenge when you need to spend an extra hour in the edit room making sure you footage looks the way you want it.
If you are filtering your image in the field, can you expect to have as versatile an image to work with in post? The simple answer is no. Once you have affected that video by using a filter, the ability to remove that effect is gone. What hits the sensor is what you have to work with. You are committed to the effect created by the filter. Any attempt at a post production tweek is limited by how much the filter/s used changed the video, so user beware!
There is a time and a place for filtering, and we have concluded that the determining factor for that is time, regardless of the product you are putting out. If you can spend countless hours in the edit room, I am sure that you can replicate or even improve upon a filtered look you get out in the field. All the while maintaining image versatility, be it native camera output, LUT corrected, LOG or RAW. Filtering simply locks you into a look that is harder to correct later. But, If you need to upload a video right after shooting or feel like you will be rushed in the edit room, the right filter in the field can give you a superior look to a stock Rec 709 look off your sensor.
Shooters using DSLR rigs might prefer using screw-on lens mounted filters, rather than buying a matte box with with 4 x 4 or 4 X 5.65 inserts. Screw-on lens mounted filters are advantageous for those run and gun DSLR rigs due to their lightweight nature and ease of mounting/storing. Serious cinema type shooters will appreciate the versatility and flexibility of a Matte box.
If you’re a run and gun DSLR shooter who needs to put out content fast, get yourself a few solid filters you can slap on that bad boy to achieve a higher quality or designed look.If you’re shooting video that you want to spend some time with in post, grading, coloring, tweaking, ect… maybe skip the filters. Use your in-camera ND filters and mess with the rest in post.