I've seen some people say that ND filters preserve the colors better for post production, and make make the image better exposed. Other people, in this video for example, say that the only thing it does is reduce the shutter speed for a more "cinematic" look. I'm only a hobbyist, but obviously, I want my footage to look as good as possible. So basically my questions are: What do they really do, and do I really need them?

ND stands for neutral density - if your ND filters affect colour grades in your footage they are not fit for purpose. Polarised filters may make the blues pop more in the image but standard shutter ND’s should remain totally neutral to the colouration. They are designed to reduce the shutter speed to create smoother images in brighter conditions without over exposure. Ultimately, to create the 180 degree rule for that cinematic feel when recording moving objects by enhancing motion blur. The Mavic series have fixed apertures so quite essential if you want that motion blur effect.

A CW Posted at 2018-1-28 16:27
ND stands for neutral density - if your ND filters affect colour grades in your footage they are not fit for purpose. Polarised filters may make the blues pop more in the image but standard shutter ND’s should remain totally neutral to the colouration. They are designed to reduce the shutter speed to create smoother images in brighter conditions without over exposure. Ultimately, to create the 180 degree rule for that cinematic feel when recording moving objects by enhancing motion blur. The Mavic series have fixed apertures so quite essential if you want that motion blur effect.

Is motion blur the only thing ND filters do?

Yep! Real ones anyway. TBH I try not to use them where I can but sometimes, especially in the summer, they are a must for recording video.

The easiest way to think of these filters is that they are merely sunglasses for your camera.

StanfordWebbie Posted at 2018-1-28 17:38
The easiest way to think of these filters is that they are merely sunglasses for your camera.

It's also good for people to know how they work too!

If you want your footage to look as good as possible then in some situations you will need them, buy the best ones you can afford. If you can only afford one set buy the ones without the polarizer layer as in some situations it'll make it virtually impossible to colour correct.

Guys, What are the most common ND filter strengths used? Thinking of getting the PolarPro Vivid (PL) set, but they do also sell the ND/PL 32 standalone. Would the 32 be overkill for most conditions?

Oranges Posted at 2018-1-29 04:49
Guys, What are the most common ND filter strengths used? Thinking of getting the PolarPro Vivid (PL) set, but they do also sell the ND/PL 32 standalone. Would the 32 be overkill for most conditions?

16 and 32 are the two I use the most. If you really want to stick to the 180º shutter rule, you'll need 32 on sunny days

ND filters are used to bring your shutter speed down to the speed you want for your image. If you are using them in photography you might use them to bring the shutter speed down to capture long exposures of things like rivers or moving cars. If you are using them in videography then they are used to bring the shutter down to meet the 180 degree shutter rule for cinematic capture. E.G. capturing at a 24fps needs a shutter of 50.
The value of the Neutral Density filter you could use is based on the environment you are shooting in. If its just a normal day and you are at ISO 100, 24 fps, 50s and your highlights are just on the edge of blowing out, stick a ND2 on. If its a bit sunny use ND4, if its really sunny and you are shooting bright stuff try the ND8, if you are at the beach and its really bright use the ND16. If you are in the snow and its sunny ND32 might work.

Polarised (PL) filters are a bit different. Light is reflected off surfaces at many different angles. A polariser will only accept light travelling at a specific angle based on the rotation of the filter. You can have ND/PL filters. The ND part of the filter will reduce the amount of light going into the lens and the PL part will polarise the light. The PL will reduce the glare coming from an object or reflections on glass or water. So if you wanted to capture some cinematic footage of a lake on a nice bright day you might use ISO100, 24fps, 50shutter, ND4(pl)-ND8(pl). rotate the filter to set polarisation before you take off to remove the glare and reflections from the water. Fly and shoot

I personally have a £20 set of neewer filters ND4(pl)-ND16(pl) and they work perfectly.

0Kajuna0 Posted at 2018-1-29 04:59
16 and 32 are the two I use the most. If you really want to stick to the 180º shutter rule, you'll need 32 on sunny days

Thanks for your prompt reply

Are you using 16,32 (Non-PL)? Because from what I understand, Polarizing filter itself reduces F-stop by 1-2 counts as well.

So i'm thinking an ND32/PL might equate to an ND64 ?

Thanks again

Oranges Posted at 2018-1-29 05:04
Thanks for your prompt reply  

Are you using 16,32 (Non-PL)? Because from what I understand, Polarizing filter itself reduces F-stop by 1-2 counts as well.

I use 32 without PL, just because that's what I own, but even with 8 and 16, where I have both, I use the non-PL unless I have time to test in which position the polarisation is creating the desired effect on snow,  water or sky... so I don't use them much.

I assume they take the 1 stop light decrease caused by the PL into account when creating and labeling the filters, I have them here and 16 vs 16PL appear to produce the same effect, except on reflective surfaces, of course.

0Kajuna0 Posted at 2018-1-29 05:21
I use 32 without PL, just because that's what I own, but even with 8 and 16, where I have both, I use the non-PL unless I have time to test in which position the polarisation is creating the desired effect on snow,  water or sky... so I don't use them much.

I assume they take the 1 stop light decrease caused by the PL into account when creating and labeling the filters, I have them here and 16 vs 16PL appear to produce the same effect, except on reflective surfaces, of course.

Hmm, thats interesting. I assumed they didnt take that into account since Vivid set has ND4,8,16 whereas Shutter set has 8,16,32. That is good info.

Perhaps i'll go for the ND/PL .

Thanks for the info! Would have never known they were calibrated to ND already.

0Kajuna0 Posted at 2018-1-29 05:21
I use 32 without PL, just because that's what I own, but even with 8 and 16, where I have both, I use the non-PL unless I have time to test in which position the polarisation is creating the desired effect on snow,  water or sky... so I don't use them much.

I assume they take the 1 stop light decrease caused by the PL into account when creating and labeling the filters, I have them here and 16 vs 16PL appear to produce the same effect, except on reflective surfaces, of course.

With our filters, the Polarizer is built into the filter rating so a ND8/PL will reduce 3 stops of light.
The polarizing aspect at most will knock off 1-stop if your scene is 90% sky. I would say on average the polarizer would reduce 0.25 to 0.5 stops under most scenes (half sky / half ground).

Happy to answer any questions!
-Jeff from PolarPro

Nice video!

Your question What they really do has been well answered below. Do you really need them.. i would say yes. i find i use my 16 most and then my 32 second most

Short answer, yes.

Long answer:
To understand why an ND is important first we need to understand properly exposing our photographs with the exposure triangle. Shutter speed, aperture, and ISO. Each of these three settings affects the amount of light that reaches the sensor. Shutter speed is the amount of time light is exposed. Aperture is the size of the hole at which light passes through to the sensor (think your eyes pupil opening and closing). ISO is the sensitivity of the sensor to light. We want to adjust each of these to capture the desired effect (Motion blur, freeze frame, shallow depth of field, etc.) This is a very basic explanation of course. Feel free to read more on this if you want.

With the Mavic, we only have control over two of these to get the proper exposure. Without the ability to adjust the aperture on the Mavic, the ND filter allows us to capture the proper exposure of a scene easier. This becomes increasingly important when we talk about capturing video. Because in video, our shutter should be double our frame rate (24fps = 1/50th shutter). This creates the most natural motion blur in our videos. Because the Mavic aperture is fixed wide open, we can't achieve this rule and get a proper exposure. So we introduce an ND filter to reduce the amount of light. Which, allows us to meet our double frame rate rule.

Every rule is meant to be broken, you can achieve a great looking image without meeting the shutter rule, as long as motion is not a large factor in your video. An ND filter will not make your videos instantly fantastic, but they will help you get closer to a proper exposure.

Hope this helps.

Brian88 Posted at 2018-1-29 14:25
Short answer, yes.

Long answer:

Thanks for the explanation. I think for now I'll get by fine without them, but I may get some in the future.

That's a great explanatory video, thanks for sharing. My take on this is that beginners should put off worrying about ND filters and DLOG and such and learn to control their aircraft first, honing shooting and exposure skills as they go. The hobbyist may discover they're fine with the default out-of-box experience, and won't be encumbered with all this extra work and learning curves in prep, execution, and post that video pros and enthusiasts spend to squeeze out the best possible quality.

Brian88 Posted at 2018-1-29 14:25
Short answer, yes.

Long answer:

Great explanation. Just wanted to add that nowadays you can generate motion blur digitally if you don't have the appropriate NDs on location. It's never the same but it can often be good enough.

You do not NEED them, you should WANT them however. They allow your camera to take better photos in harsh light (like a lens sunglasses) which results in more cinematic footage

ironicgull68 Posted at 2018-1-29 16:30
You do not NEED them, you should WANT them however. They allow your camera to take better photos in harsh light (like a lens sunglasses) which results in more cinematic footage

I thought polarizers do that?

Are the Neewer brand ND filters okay? The Polar Pro ones are 3x the price. These are the ones I am talking about https://www.amazon.com/Neewer-Pi ... mavic+Pro+nd+filter

Let's face it, if you want smooth, natural looking footage, you're limited to two combinations of frame rate and shutter speed:

1.  24fps @ 1/48 second shutter speed, or
2.  30fps @ 1/60 second shutter speed.

Everything else is going to give you some kind of "effect" which you, as the film maker may want, or not.

In order to get one of those two combinations in bright light, you're either going to be lucky (the light is perfect), or your going to have to stop some light getting to the sensor behind the lens. To do this, you need to give the lens sunglasses. That's what an ND filter does... Blocks light, without changing its color so that you can get your frame rate/shutter speed combo to one of the two settings above.

If it's dark, then you need to add light, either by adding light (duh!) or increasing the sensitivity of the sensor (increasing the ISO setting), which also increasesv noise in the image.

MavicMan101 Posted at 2018-1-29 19:41
I thought polarizers do that?

A polarizer will add additional contrast and saturation. If, it's rotated correctly on the lens and the correct angle from the sun. An ND filter simply reduces the light to the sensor allowing you to lower your camera settings and capture motion in both photos and video. An ND filter is not meant to add color or any other effect to your footage. Although, most do as a side effect of adding an additional piece of glass in front of the lens.

MavicMan101 Posted at 2018-1-29 19:43
Are the Neewer brand ND filters okay? The Polar Pro ones are 3x the price. These are the ones I am talking about https://www.amazon.com/Neewer-Pieces-Filter-Mavic-Quadcopter/dp/B06ZZP9PXW/ref=sr_1_1?ie=UTF8&qid=1517283740&sr=8-1&keywords=Neewer+mavic+Pro+nd+filter

The more you pay the better the quality. And the balance of the filter on the gimbal. Worth the extra bucks if you are a footage quality freak.

MavicMan101 Posted at 2018-1-29 19:43
Are the Neewer brand ND filters okay? The Polar Pro ones are 3x the price. These are the ones I am talking about https://www.amazon.com/Neewer-Pieces-Filter-Mavic-Quadcopter/dp/B06ZZP9PXW/ref=sr_1_1?ie=UTF8&qid=1517283740&sr=8-1&keywords=Neewer+mavic+Pro+nd+filter

Neewer tends to be good, for the price however. there are a lot of cheaper off brand neewer products but if they work, they work

MavicMan101 Posted at 2018-1-29 19:43
Are the Neewer brand ND filters okay? The Polar Pro ones are 3x the price. These are the ones I am talking about https://www.amazon.com/Neewer-Pieces-Filter-Mavic-Quadcopter/dp/B06ZZP9PXW/ref=sr_1_1?ie=UTF8&qid=1517283740&sr=8-1&keywords=Neewer+mavic+Pro+nd+filter

I have Polar Pro I love the difference compared to the DJI ones. 16 and 32 are my most used ones.
One thing that I can't see others don't say is that you "must" combine them with Manual mode i.e. to be able to get "correct" FPS. Depending on light you might be forced to Switch so you for instance get correct shutter speed in correlation to FPS.

Happy flying

ironicgull68 Posted at 2018-1-30 12:05
Neewer tends to be good, for the price however. there are a lot of cheaper off brand neewer products but if they work, they work

I have the neewer set of ND filters. They do what they should, they never ever gave me a calibration issue they haven't cracked at all, overall work fine and I still haven't seen any evidence why you should pay triple the amount for a set.

one thing i can say is make sure you get a ND32...The 16 is never enough on a sunny day.