Get the best out of your drone
ND filters for your drone. Why?
Why do you need filters for your drone you might wonder?
On most drones the aperture is fixed so the only variables you can change to get the correct exposure are ISO and shutter speed.
If we want that cinematic motion blur in our video’s, which is created by using a reduced shutter speed in relation to your fps (frames per second) you are filming at, we need to reduce the light that is hitting the sensor of the camera.
The only way we can do that is by using ND filters, since we can’t lower the ISO further.
If we film without a ND filter during daytime the shutter speed will be around 1/1600th or something similar. This high shutter speed will result in shaky footage (rolling shutter effect), better known as “jello”.
In the old days cinematic filmmakers used the 180 degree shutter rule to calculate the shutter speed to get that motion blur. Without going into details, this rule still applies to modern camera’s. For the use of this rule on our modern day camera’s, you take double the frame rate you are shooting at as your shutter speed.
Most of us use 24 fps so we need a shutter speed of 1/48th, with 1/50th being the nearest possible.
Film at 50fps
How do we do that?
If we film during a sunny day and the camera gives us a shutter speed of 1/1600th at ISO 100 we need to use a 5 stop ND filter (ND32) to reduce the shutter speed to 1/50th. This way we are filming at the optimal settings to achieve the smoothest video.
Different conditions, require different strength of ND filters.
You need to calculate the needed reduction in f-stops regarding your native shutter speed. When you don’t know how to do this, you can use the table below as a guide and check the actual shutter speed on your DJI interface.
- ND4 2 stops – dusk or dawn
- ND8 3 stops – mostly cloudy
- ND16 4 stops – mostly sunny
- ND32 5 stops – sunny midday conditions
- ND64 6 stops – snow, white sand or very bright conditions
Especially when you shoot moving objects or seascapes the jello effect can look very unnatural.
Reducing the shutter speed will give us that natural feeling we are looking for.
Filter kit for the DJI Mavic Pro and Phantom series
You need to have light weight filters because the gimbal is calibrated to operate smoothly without the filters attached.
The NiSi filters are only 1.2 grams, minimising the effect on the gimbal.
If you are going to attach or remove the filters, please do so when the drone isn’t powered.
Else you would be putting force on the gimbal while it is trying to keep level and you could damage it.
The filters are fitted with soft padding on the inside which will slide smoothly over the camera and assures a solid fix. I have been flying the drone during high winds, with high forward speeds and had no trouble with the filters staying in place. The filters can be removed by gently pulling them from the camera.
An other neat feature is the protective coating that can also be found on the cinema and ND filters. Water and dirt can be easily removed without any left overs and water will fall off the filter when you are flying.
The NiSi filters have no colour cast or vignetting (not even the ND 64) meaning that your colour profiles can still be used without tweaking them. The CPL (circular polariser) filter works like you would expect, it minimises glare on glass and water and does this well.
When you want to make professional looking video’s with your drone you will need ND filters.
With the NiSi ND filter kit for the DJI Mavic Pro and Phantom you have all the filters you would need.
Various strength of ND filters, a CPL and a clear filter.
Ok now show me some results
As a photographer I am using ND filters 80% of the time. When I first flew with the drone, I wanted to have a soft Grad ND filter for it (can you make them NiSi?).
That would help me even more with drone photography. While shooting film I noticed the jello effect, but didn't knew how to overcome that.
After reading about it online and attaching the correct ND filter to my drone, the difference was obvious.
Have a look at the video to see the difference side by side and see how the waves roll smooth when the filter is attached.
The video isn't meant to be professional, it isn't colour graded, it is made just to show you what the (correct) ND filter does.