ND Filters and Exposure Calculators…

[Flashheart]

To whom it may prove useful, you can accurately calculate the exact ND filter required using a long exposure calculator. I’ve used this technique many times now and it is accurate on all Freewell ND filters.

2 stop = ND4
3 stop = ND8
4 stop = ND16
5 stop = ND32
6 stop = ND64

Shooting at 30fps, F2.8 and a shutter speed of 1/500 required 3 stops (ND8) for the 180 rule.

 

[MAvic_South_Oz]

It's always going to vary a little with drones, turning towards / away from different light etc.
Really, for video especially (rather than long shutter photos), a good guess becomes easier as you trial ND filters.

For video, blue hour I just leave an MC-UV on.
Use an ND 4 or 8 on the verges, golden hour or slightly lighter.
Between that and mid morning and same mid afternoon to sun still a little above the horizon, I find the ND16 is good.
Middle of the day ND32, haven't used my ND64 much at all, but might be handy one day for white sand beaches or snow.

For slow shutters, unless you have a variable aperture camera drone, you will probably need much stronger ND filters to do anything like smooth water shots.
Tried my ND64 on a tidal movement once, very marginal effect (that was an M1P).
I'd estimate 8 to 20 stops would be required to make a decent difference, and then I have to keep the drone very still.

I have a NISI app that does the estimates like you posted above, and I did have one PolarPro does too, was interesting to play around with inputs and see what filters they recommended.
It was more for traditional camera though I feel.

Cheers.

 

[Dronut]

I use an app called ND Expert. It has a drone mode.

 

[MAvic_South_Oz]

I use an app called ND Expert. It has a drone mode.

Cheers, will take a look for that, and see how it might help in comparison to what I might normally choose.

 

[whistlen2602]

I use an app called ND Expert. It has a drone mode.

Is it an iOS app? I found ND Filters.

 

[MAvic_South_Oz]

Is it an iOS app? I found ND Filters.

Might be android only, I couldn't see it in the Apple offerings.

 

[Dronut]

Is it an iOS app? I found ND Filters.

It's for Android.

 

[frcaloy]

Whenever I manually set frame rates and shutter speeds to 30fps and 1/60, I have to use ND filters here in sunny Philippines. Instead of guessing how many stops are necessary for that particular exposure, I can bring along a camera where I can determine correct shutter speeds based on the histogram.

Now, I can convert shutter speed to ND stops to arrive at say 1/60. No more guessing. I don't have to bring back the drone just to change ND filters. I can get it right first time out. The App is the Exposure Calculator.