Could anyone give a brief dummys guide to ND filters?

[rabidhyena]

Hi.
They are all so over this forum that I now conclude they must be essential.
I get the objective of having a shutter speed double the frame rate but could anyone give some more advice?
Which grades are most useful? How many in the set?
How do you assess which to put on? Or do you just eyeballs the sky before taking off?
Do you store with it attached etc etc.
Many thanks.

Sent from my SAMSUNG-SM-N920A using MavicPilots mobile app

 

[Glen e]

The cliff notes Version:

The shutter speed is adjusted with ND filters. Use about ND16 on sunny days, ND32 in bright snow, ND8 during the golden hour, ND4 on cloudy days. In general that should work if shooting 60fps, but you should play with it to get the feel of the settings.

 

[AyeYo]

It depends what kind of shooting you do. I'm in the mountains so I shoot snow on bright days and I shot a lot in cold weather. The bright light ups the shutter speed to unacceptably fast and the cold increases jello in the footage that's exacerbated by the high shutter speed.

In my case, they're an absolute requirement because it's jello city without them. I also like the polarization on the Polar Pro combo filters because it massively cuts the glare from the snow and the high altitude sunlight.

As for which to use, an ND16 has proven to be plenty for all but the most glaringly bright mid-day snow scenes. I really need to pick up an ND32 for those. I wish one of these manufacturers would start selling them in ND8, ND16, ND32 combos, because that's by far the most useful for the Mavic. The ND4 is mostly unnecessary and short of shooting in a snow bowl or curved glacier area in perfectly clear, mid-day skies, I cannot see what you'd need an ND64 for, unless you're taking artsy motion blur stills.

 

[SrMi]

What I do is start Mavic without filters and see what is the minimum shutter speed I can get (ISO 100). Then I compute the necessary ND filter and mount it:

ND4 (2 stops reduction), e.g., 1/200sec -> 1/50 sec
ND8 (3 stops reduction), e.g., 1/400sec -> 1/50 sec
ND16 (4 stops reduction), e.g., 1/800sec -> 1/50 sec
etc.

1 stop means reduction of shutter-speed by half, e.g. 1/120sec to 1/60sec.

Hope this helps.

 

[Cimriver]

Just to make sure I am understanding this correctly, you put the your best guess ND filter on, point the drone in the direction you will be shooting and observe the the video feed on your smart device to determine if you have the correct ND filter on. If it looks good to you go for it? If not try a different filter?

 

[Neto]

Just to make sure I am understanding this correctly, you put the your best guess ND filter on, point the drone in the direction you will be shooting and observe the the video feed on your smart device to determine if you have the correct ND filter on. If it looks good to you go for it? If not try a different filter?

1. Set the camera to Manual.
2. Set ISO to 100.
3. Set the shutter speed you think is appropriate
NOW:
If the shutter speed on the app without the filter is lower than 1/50 (i.e. 1/200, 1/400, 1800), you should use the filter.
The more bright is the the scene, the darkest should be the filter (higher ND number)
Your goal is to get the shutter speed as close as 1/50 as you can

 

[Cimriver]

I understand the goal of twice the frame rate for proper shutter speed, but I as far as determining you have the right exposure with the ND filter is simply to judge it based upon what you are seeing on the smart device image?

 

[AyeYo]

I understand the goal of twice the frame rate for proper shutter speed, but I as far as determining you have the right exposure with the ND filter is simply to judge it based upon what you are seeing on the smart device image?

That isn't really all that reliable, as the scene can actually be darker or lighter depending on the brightness capability of the screen you're looking at, sun glare, your eye sight (or lack of), etc. You need to enable the histogram and watch that. Try to keep your exposure centered. You can also look at the EV and try to keep it within+ or - 0.7, depending on whether you're trying to expose for highlights or shadows.

 

[Neto]

I understand the goal of twice the frame rate for proper shutter speed, but I as far as determining you have the right exposure with the ND filter is simply to judge it based upon what you are seeing on the smart device image?

Well...there is some "interpretation" needed. (As AyeYo said, histogram is the tool to make sure you have the perfect exposition)
You set all variables (ISO=100, shutter 1/50 with the right ND), then evaluate if the image is what you like (Or histogram is mostly centered).

Personally, I always go fot an image a little darker, and fix it with color grading on FinalCut.

Since you are reducing brightness with ND filter, if you use ND4 and at 1/50 the scene is too dark, probably you don't need to use a filter at all.

 

[Cimriver]

Well that is what I was thinking, Just kind of a guess really. The Histogram is a great idea.

 

[Neto]

Well that is what I was thinking, Just kind of a guess really. The Histogram is a great idea.

The histogram theoretically remove any guessing. But also all the fun

 

[SrMi]

Just to make sure I am understanding this correctly, you put the your best guess ND filter on, point the drone in the direction you will be shooting and observe the the video feed on your smart device to determine if you have the correct ND filter on. If it looks good to you go for it? If not try a different filter?

I start Mavic Pro without any filters and in automatic exposure mode. I hold it to measure the shutter-speed (visible in DJI GO app). Let's say, it tells me 1/400 secs. This means that I need a 3 stop reduction (1/400sec -> 1/50sec), i.e. ND8 filter. I turn it off, mount the filter and then take off. The light can change while flying, though. PolarPro has an app (iOS/Android) that can help you with computing the right filter.

 

[sportfisher23]

Is this applying only for video? How about stills? I am usually snapping at sunrise and sunset. Also at or near night at bright lights or skyline lights.
Any initial thoughts?

My instagram is @realvsk for idears ...


vsk

 

[SrMi]

Is this applying only for video? How about stills? I am usually snapping at sunrise and sunset. Also at or near night at bright lights or skyline lights.
Any initial thoughts?

My instagram is @realvsk for idears ...


vsk

Stills do not need ND filter except if you want a long exposure effect (e.g. smooth water surface, etc). For stills there is no rule depending on fps as is with video. IMO, ND filter is a must to achieve great video footage, but not really needed for stills.

 

[sportfisher23]

Thanks!
Vsk

Sent from my SM-G900V using MavicPilots mobile app

 

[Peter Barnes]

Is this applying only for video? How about stills? I am usually snapping at sunrise and sunset. Also at or near night at bright lights or skyline lights.

vsk

It all depends on the amount of light you are videoing in - at sunrise or sunset you may not need to use an ND filter to get the shutter speed down to twice the frame rate. But as explained above, see what the shutter speed is at ISO 100, work out how many stops you need to get the speed down to what you need, then mount the appropriate filter. No guesswork needed.
(There seems to be a common misconception that ND filters will help with the Mavic camera's relatively limited dynamic range, i.e. its ability to record a wide range of tonal values from dark to light without having either all black or all white recorded in the dark and light areas - typical of a sunset for example where the sun is ultra bright and shaded areas may be quite dark. My advice - avoid the cliche of the setting/rising sun, but use that time to photograph what the lovely light is illuminating. The only way to deal with a dynamic range that is too wide in stills photography is to shoot a range of exposures and blend them in post-processing)

 

[deltalimatango]

I start Mavic Pro without any filters and in automatic exposure mode. I hold it to measure the shutter-speed (visible in DJI GO app). Let's say, it tells me 1/400 secs. This means that I need a 3 stop reduction (1/400sec -> 1/50sec), i.e. ND8 filter. I turn it off, mount the filter and then take off. The light can change while flying, though. PolarPro has an app (iOS/Android) that can help you with computing the right filter.

Pretty much how I do it. I even use this method when shooting with my DSLR and throw on an ND filter. I use Lee Filters and they have an app as well to help you calculate the exposure values.

 

[AyeYo]

It all depends on the amount of light you are videoing in - at sunrise or sunset you may not need to use an ND filter to get the shutter speed down to twice the frame rate. But as explained above, see what the shutter speed is at ISO 100, work out how many stops you need to get the speed down to what you need, then mount the appropriate filter. No guesswork needed.
(There seems to be a common misconception that ND filters will help with the Mavic camera's relatively limited dynamic range, i.e. its ability to record a wide range of tonal values from dark to light without having either all black or all white recorded in the dark and light areas - typical of a sunset for example where the sun is ultra bright and shaded areas may be quite dark. My advice - avoid the cliche of the setting/rising sun, but use that time to photograph what the lovely light is illuminating. The only way to deal with a dynamic range that is too wide in stills photography is to shoot a range of exposures and blend them in post-processing)

Or just shoot exposure brackets. I AEB every still shot I take with this thing and you'd never know the dynamic range sucked.

 

[sportfisher23]

Thanks Peter B. I do try to get the red / orange susnset / sunrise illuminated objects when possible but I still like getting a nice red ball sunset too. I have been happy with exposure compensation and messing around with manual focus at night. But I see the more critical thing is shutter speed to frame rate for video.

Thanks!

vsk

 

[KiterTodd]

1. Set the camera to Manual.
2. Set ISO to 100.
3. Set the shutter speed you think is appropriate
NOW:
If the shutter speed on the app without the filter is lower than 1/50 (i.e. 1/200, 1/400, 1800), you should use the filter.
The more bright is the the scene, the darkest should be the filter (higher ND number)
Your goal is to get the shutter speed as close as 1/50 as you can

Neto, this is great, thank you.
It is the exact my-head-is-already-full-with-too-much-info dummies guide I personally needed.
I saved this text on my phone so the next time I'm in the field... I will remember to check it.

PolarPro let me custom order a single filter (ND16/PL) which I'm bringing on a snow trip next week. I figure if I don't mind mucking with filters and the results are significantly better, I'll buy a set.

Once you are filming, is the iPhone screen a good representation of how the shot is going? If things are looking dark on the screen are you generally able to bring up the shadows in post?
Or, if it looks dark on my screen should I land and take the thing off? (I know, I know... switch to auto and look at the ISI & frame rate. BUT, I'll likely be in cold weather and will want to make quicker decisions and limit my screwing around time...)