Please select Into the mobile phone version | Continue to access the computer ver.
ND Filter - Am I Doing it Wrong?
2125 29 2016-3-25
Uploading and Loding Picture ...(0/1)
o(^-^)o
flyfishnevada
lvl.2
United States
Offline

I grabbed a set of Polar Pro filters for my P3 standard.  I've got a regular polarized filter, an ND4 and an ND8.  It's sunny today, so I slipped the ND8 filter on and I couldn't get the frame rate anywhere near 1/50.  Best I could do was 1/200.  I was shooting at 100 iso and 24 fps.  Am I missing something or do I need to go down to a ND16, ND32 or ND64?  I'm not sure they even make those that will fit the P3 Standard.  I definitely not getting that nice motion blur when I pan.  It's choppy but at least the colors look a little richer.

Thanks.

2016-3-25
Use props
FAS1
Second Officer

United States
Offline

ANy pics/video to show the problem?
2016-3-25
Use props
pi-inthesky
First Officer
Flight distance : 13058 ft
United Kingdom
Offline

The ND16 would have brought you closer to your desired shutter speed polarpro have the full range.
2016-3-25
Use props
flyfishnevada
lvl.2
United States
Offline

No video.  Well, I have video but I'd have to upload and all that.

So, I just need to get a ND16 or higher.  I mean the video looked better and I used the optical flow effect in PP.  It looked a little better.
2016-3-25
Use props
Anderjon
lvl.4
Flight distance : 666893 ft
United Kingdom
Offline

Best method I've found is to

1. select my preferred video resolution and frame rate
2. Select the shutter speed (double frame rate) and as low an ISO as I can (usually 100 / 200)
3. Then I check the histogram (under the camera settings). If it's showing a nice "mountain curved shape in the middle then I'm good to go. If it's off to the right, then I need to go up one on the ND filter. If the histogram is off to the left, then I need to go down an ND filter. I keep adjusting the filter strength until the histogram is in the middle and I'm all set.

For this to work, you need a good range of filter. 4 to 32 is a good start.
2016-3-25
Use props
aopisa
Second Officer
Flight distance : 430686 ft
Offline

Anderjon Posted at 2016-3-26 10:06
Best method I've found is to

1. select my preferred video resolution and frame rate

Do you really use a #4 filter?  Seems like it's practically useless.
2016-3-25
Use props
Anderjon
lvl.4
Flight distance : 666893 ft
United Kingdom
Offline

I live in Scotland :-). Adds a small amount of natural motion blur without darkening an already sub-par lit sky!
2016-3-25
Use props
Geebax
Captain
Australia
Offline

Anderjon Posted at 2016-3-26 13:06
Best method I've found is to

1. select my preferred video resolution and frame rate

Just a little note on that. Professional cameramen tend to follow a rule called ETTR, or Expose To The Right, meaning that when they view the histogram, they tend to push the display as far to the right as you can without crushing it. This tends to better expose the darker areas in the image and bring out detail in the blacks.
2016-3-25
Use props
Anderjon
lvl.4
Flight distance : 666893 ft
United Kingdom
Offline

Geebax Posted at 2016-3-26 03:04
Just a little note on that. Professional cameramen tend to follow a rule called ETTR, or Expose To ...

Really? As a professional photographer I tend to go for as flat an image as possible with a spread across the centre which allows for the maximum dynamic range in post. I guess there's a few ways to skin the proverbial cat :-)
2016-3-25
Use props
ROROFLIX
lvl.3

United States
Offline

If it's a bright sunny day, ND16 will not get you to a 1/50 shutter. You will need at least a ND32 or ND64. If ND64 gets you too underexposed you can always bump ISO. All 3 are very useful ND filters depending on brightness.
2016-3-25
Use props
Geebax
Captain
Australia
Offline

ROROFLIX Posted at 2016-3-26 14:29
If it's a bright sunny day, ND16 will not get you to a 1/50 shutter. You will need at least a ND32 o ...

I have been using the technique in digital cinematography for several years now, particularly when shooting RAW cinema material. I find it gets the best out of the sensor. This is a good article on the subject: https://en.wikipedia.org/wiki/Exposing_to_the_right

2016-3-25
Use props
AG0N-Gary
Captain
Flight distance : 700846 ft
United States
Offline

The idea of ETTR is to raise it slightly above optimum, allowing it to be brought down again in post.  That decreases the noise content of the image.
2016-3-25
Use props
Anderjon
lvl.4
Flight distance : 666893 ft
United Kingdom
Offline

AG0N-Gary Posted at 2016-3-26 03:31
The idea of ETTR is to raise it slightly above optimum, allowing it to be brought down again in post ...

You live and learn! I'll give it a try :-)
2016-3-26
Use props
Nightingale
lvl.3
Flight distance : 44301 ft
Netherlands
Offline

Or get yourself a pair of these http://www.phantomfilters.bigcartel.com and stack 'em behind the glass of your Polar pro filters and you'll get the same result quick and cheap!
2016-3-26
Use props
nigelw
First Officer
Flight distance : 518084 ft
United Kingdom
Offline

Here's how it works (without using a separate light meter)...

Get your exposure right without a filter.
Whatever the setting is (in your case, it would be 1/800sec), decide what you're after (1/50sec) & calculate it from there.

Divide the shutter speed you have by the shutter speed you want to find the filter factor, so 800/50 = 16.  You need an ND16 filter.

The number 16 in ND16 is the filter factor.  It means it will reduce light transmission 16 times or 4 stops.  Each stop equates to halving or doubling the shutter speed.

So: -

from 1/800 to 1/400 is 1 stop = twice as much light gets in - you'd need ND2
from 1/800 to 1/200 is 2 stop s= 4 times as much light gets in - you'd need ND4
from 1/800 to 1/100 is 3 stops = 8 times as much light gets in - you'd need ND8
from 1/800 to 1/50 is 4 stops = 16 times as much light gets in - you'd need ND16
2016-3-26
Use props
nigelw
First Officer
Flight distance : 518084 ft
United Kingdom
Offline

Nightingale Posted at 2016-3-26 11:31
Or get yourself a pair of these http://www.phantomfilters.bigcartel.com and stack 'em behind the gla ...

The problem with stacking filters is you increase the number of surfaces the light travels through.  That always reduces image quality, without exception.  Also, cheap filters will usually degrade the image quality a lot more than expensive ones.  There are good reasons for it too.
2016-3-26
Use props
bluesky skydive
lvl.2
Canada
Offline

nigelw Posted at 2016-3-26 09:11
Here's how it works (without using a separate light meter)...

Get your exposure right without a fil ...

thats a good explanation THX!!
2016-3-26
Use props
nigelw
First Officer
Flight distance : 518084 ft
United Kingdom
Offline

Anderjon Posted at 2016-3-26 11:19
You live and learn! I'll give it a try :-)

I use ETTR always in my photography.  One problem many people have is the image on-screen as you record or play back looks washed out, so it's difficult to judge what it'll look like after processing.  You have to rely on your histogram & zebras.  I often take a normally exposed image, or one which looks the way I hope to achieve as a reference.  People looking at your monitor just think you're a crap photographer
2016-3-26
Use props
kgarrison
First Officer
Flight distance : 10062215 ft
  • >>>
United States
Offline

The reasoning behind ETTR is that detail is lost in the shadows and is maintained better in the highlights. If you underexpose the shadows, there is less ability to recover detail. If you overexpose the highlights a little, there is still latitude to recover detail in post. We often talk about exposing for the shadows so that as long as the highlights are not totally blown out, we have room to correct it.
2016-3-26
Use props
flyfishnevada
lvl.2
United States
Offline

That all makes sense.  I'm an amateur so a little motion stuttering isn't the end of the world.  I'd probably be better off keeping my camera moves on the slow side to counteract the motion stuttering and speed it up in post if I want.  Seems a shame that you can't get darker ND filters for the P3S but that is the hobbiest/entry level drone.  As much as prices dropped during and after the Holidays, I should have stepped up a level.

In any case, I'll play with my histogram and see what I end up with.  The filters cut the glare and enhanced the color so that's a good thing.
2016-3-26
Use props
nigelw
First Officer
Flight distance : 518084 ft
United Kingdom
Offline

flyfishnevada Posted at 2016-3-26 16:04
That all makes sense.  I'm an amateur so a little motion stuttering isn't the end of the world.  I'd ...

http://store.dji.com/product/phantom-3-nd16-filter
2016-3-26
Use props
WetDog
lvl.3
Flight distance : 1131886 ft
United States
Offline

Anderjon Posted at 2016-3-25 19:24
Really? As a professional photographer I tend to go for as flat an image as possible with a spread ...

All ETTR does is suggest that you fill up the right hand 'bins' in the exposure bucket first because you get more information (more photons) and less noise.  You still want to capture the entire range of contrast (a flat picture) and then manipulate in post for desired effect.  So a high contrast scene will have tonalities from light to dark - you expose for everything - while a flatter scene might not use the entire dynamic range.

What ETTR suggests to do in the latter case is make sure that all of those photons are in the brightest values because you can use less of them to get a darker exposure without dragging out noise.

The problem in video is you have another problem - the blurring effect between frames.  When you want a digital video to look like a film shot because our brains have been taught that 'film is right' you need to have some blurring in each frame.  Which means you have to shoot at slower speed than you would to get an acceptable still image (since blur in an anathema to a still image unless you are going for some sort of artistic effect).

On a P3, you can't adjust the aperture so the only thing you can adjust is ISO and shutter speed.   And on the P3 you can't decrease the ISO below the base value of 100.  So you have to slow the shutter speed.  To keep the exposure somewhere where it belongs the only way you can do that is fiddle with an ND filter.  If you underexpose, ie, don't 'shoot to the right' you will get a noisy shot if you try to bring up the exposure.  But typically you are wanting to SLOW the shutter so you end up overexposing  without an ND - even in Scotland.

The base problem is that the P3 has a very limited camera.  Of course, the P3 cost less than a decent video camera monitor much less a lens or a camera body so DJI can only do so much.

The other way to do this is in post - blur the image in an editor.  That's non trivial and if not done correctly looks really bad.
2016-3-26
Use props
flyfishnevada
lvl.2
United States
Offline

nigelw Posted at 2016-3-26 09:13
http://store.dji.com/product/phantom-3-nd16-filter

Not for P3S unless I'm missing something.

I found some ND filters on ebay from Ditzco.  I'll have to stack them to get up to the higher ND values but whatever.  For $31, why not?
2016-3-26
Use props
nigelw
First Officer
Flight distance : 518084 ft
United Kingdom
Offline

flyfishnevada Posted at 2016-3-26 18:39
Not for P3S unless I'm missing something.

I found some ND filters on ebay from Ditzco.  I'll have ...

I don't think there's any difference between any P3 cameras besides the technical spec.
2016-3-26
Use props
flyfishnevada
lvl.2
United States
Offline

nigelw Posted at 2016-3-26 12:00
I don't think there's any difference between any P3 cameras besides the technical spec.

I looked because I wasn't sure.  I can't unscrew the lens on my P3S.  I think that's the difference.  My filters slip on instead of screw on.  The new ones I ordered slip on too.
2016-3-26
Use props
nigelw
First Officer
Flight distance : 518084 ft
United Kingdom
Offline

flyfishnevada Posted at 2016-3-26 22:20
I looked because I wasn't sure.  I can't unscrew the lens on my P3S.  I think that's the differenc ...

Well that sucks!  Maybe try Nightingale's suggestion then unless you can find something better.
2016-3-26
Use props
flormo2002
First Officer
Flight distance : 4397651 ft
  • >>>
Offline

Yeah, I couldn't get less than 200 shutter speed with the ND8 today. It was almost high noon and just flying around the house so nothing worth filming that I haven't filmed already.
2016-3-26
Use props
Nightingale
lvl.3
Flight distance : 44301 ft
Netherlands
Offline

@nigelw thats why I suggested that :-). The P3S needs slip-on lenses. What I did was buying the filters from phantomfilters.com and an more expensive UV slip-on filter and put an ND16 filter behind the glas of the UV filter. I get great results, nice motionblur and little to no hickups when panning.
2016-3-27
Use props
nigelw
First Officer
Flight distance : 518084 ft
United Kingdom
Offline

I find it really odd they don't make an ND16 filter for the Standard, since there's clearly going to be the same demand as for the Advanced & Professional.
2016-3-27
Use props
flyfishnevada
lvl.2
United States
Offline

Yeah, I got the Polar Pro filter kit for my P3S but it only offers an ND8.  I looked on their website and they don't sell them individually either.  It is odd.  Just because I opted for the P3S doesn't mean I want choppy motion.
2016-3-27
Use props
Advanced
You need to log in before you can reply Login | Register now

Credit Rules