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ND Filter - the choice of one....

Polarizing fliters (PL) are problematic on drones for two reasons.
First, cameras on drones are mostly wide angle, with diagonal angle of view between approx. 75 - 84 degrees. As the polarizing effect is strongest with the sun in a certain angle to the lens, photos with blue skies tend to look ugly with a PL-filter, with half of the sky dark blue and the other half much lighter. If you try stitching such photos for a panorama it will be terrible.
Second, as everybody with experience from photography with PL-filters will tell you, you need to rotate the filter depending on the angle of the sun and lens to get full effect. That is a bit difficult when the drone is mid-air.
Taken with a ND1000 on auto.
 

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Polarizing fliters (PL) are problematic on drones for two reasons.
First, cameras on drones are mostly wide angle, with diagonal angle of view between approx. 75 - 84 degrees. As the polarizing effect is strongest with the sun in a certain angle to the lens, photos with blue skies tend to look ugly with a PL-filter, with half of the sky dark blue and the other half much lighter. If you try stitching such photos for a panorama it will be terrible.
Second, as everybody with experience from photography with PL-filters will tell you, you need to rotate the filter depending on the angle of the sun and lens to get full effect. That is a bit difficult when the drone is mid-air.
All very true so I don’t use them for panoramas or even single shots of the sky but CPL are very useful over water….
 
I have found that for most situations a 16nd is a nice middle ground.. and 99.9% of the time I'm shooting video.

I usually either go with DJI's kits or Polar Pros, but the only kit I've found from DJI is a 16, 64, and 256 which is odd. I normally use a 4 for sunsets or sunrises, and 8 for over cast days and a 16/32 for bright days. So why is the DJI kits range so wide? I wondered if it's something to do with the tiny sensor'd camera? I'm not planning on shooting solar eclipses.
 
I have found that for most situations a 16nd is a nice middle ground.. and 99.9% of the time I'm shooting video.

I usually either go with DJI's kits or Polar Pros, but the only kit I've found from DJI is a 16, 64, and 256 which is odd. I normally use a 4 for sunsets or sunrises, and 8 for over cast days and a 16/32 for bright days. So why is the DJI kits range so wide? I wondered if it's something to do with the tiny sensor'd camera? I'm not planning on shooting solar eclipses.
I agree it's a bit aggressive.
 
I have found that for most situations a 16nd is a nice middle ground.. and 99.9% of the time I'm shooting video.

I usually either go with DJI's kits or Polar Pros, but the only kit I've found from DJI is a 16, 64, and 256 which is odd. I normally use a 4 for sunsets or sunrises, and 8 for over cast days and a 16/32 for bright days. So why is the DJI kits range so wide? I wondered if it's something to do with the tiny sensor'd camera? I'm not planning on shooting solar eclipses.
I'm pretty sure it's because of the f1.7 aperture. This runs about 1½ stops more sensitive than most camera drones with fixed aperture.

So, double the ND filter from what you usually use. 16 (or nothing) during sun rise/set or overcast daylight. 64 for clear sunny day. 256 for snow, beach, ocean surface.

The 64 works well most of the time, and does a decent job of making the shutter double framerate rule work most of the time during the day.
 
It’s good the OP has picked up a VND, should make things easy, and get the best outcome.
As per most replies here, for shooting video and adhering to the 180 fps / shutter rule, you can’t just pick one for all light situations, and if you can’t get the 180 rule or close then you might as well not use one at all.
The ND for 180 rule is really only needed if flying close to your subject, and / or moving fairly fast, for most cinematic speed or far off subject shooting like landscapes it’s not so important.
 
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@MAvic_South_Oz could you explain the 180 above? Ive always understood the shutter rule to be 2x the frame rate, or usually 1/120s for a framerate of 60 (like shooting 4K/60). 180 would be a framerate of 90fps? I'm stumped.
 
@MAvic_South_Oz could you explain the 180 above? Ive always understood the shutter rule to be 2x the frame rate, or usually 1/120s for a framerate of 60 (like shooting 4K/60). 180 would be a framerate of 90fps? I'm stumped.
180 is not a shutter speed, it refers to the 180-degree shutter rule. The origin of the term is of historical interest only, in modern vocabulary it refers to… a shutter speed of twice the framerate.

Here comes the history:
Shutters on film motion picture cameras were moving circular plates with adjustable leaves, to make for various sized openings. The plate would run in sync with the film transport. 180-deg rule refers to the plate opening being 180 degrees of the full 360, or, a exposure duration of one half of the time the frame was in the gate…
 
Thanks @SethB! I wondering what sort of strange filming oddities were going on down under.

I mean, they invented Vegemite, after all 😁😁😁
 
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Hmm, I think we just took the Englishman’s marmite and made it better 😬

I don't even want to know what that is 🤣

Full disclosure: Just learned this weekend what chitlins really are (a US cultural dish).

I'll take a marmite sandwich blindly, thank you 🫣
 
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Hmm, I think we just took the Englishman’s marmite and made it better 😬
I don't even want to know what that is 🤣

Full disclosure: Just learned this weekend what chitlins really are (a US cultural dish).

I'll take a marmite sandwich blindly, thank you 🫣

An Englishman is a man who comes from England . . . ohhhhh . . . ;) :p hang on . . .


Vegemite seems a little sharper and nicer, ha ha.

Chitlins, might give it a miss for now, Scottish folk might like that !!
 
180 is not a shutter speed, it refers to the 180-degree shutter rule. The origin of the term is of historical interest only, in modern vocabulary it refers to… a shutter speed of twice the framerate.
When I'm feeling curmudgeonly (like now), I like to point out that, mathematically, the 180 rule means a shutter speed of half the frame rate, not twice. To compare two quantities, they need to be in the same units of measurement. A frame rate of 30 frames per second means, equivalently, 1/30th second per frame, and a shutter speed of 1/60th second per frame is half that. I'm usually (er, always?) accused of being pointlessly pedantic when I say that, but there is a very specific reason I believe that saying it that way makes this much clearer:
... a exposure duration of one half of the time the frame was in the gate…
... which is the simple purpose of the rule in the first place: to produce motion blurs that are half the distance objects are displaced frame-to-frame. If you shot a scene with a baseball flying past the camera and composited several frames into one photo, you would see streaks separated gaps of equal length. It's an arbitrary rule, which supposedly make video more "cinematic" because that's what film cameras do, but it's not magic.

The response I usually get is that there's no point in being so pedantic because everyone "understands" the rule as soon as you give an example like 1/60th sec for 30fps. That's true however you express the rule, and I think it's also true that most people won't understand either statement until you give an example. However, I still firmly believe that more people would really understand what the rule is actually doing if it was expressed correctly.

If the smoothness of the video is more important to you than the image sharpness when you're flying fast and close to subjects, then an ND filter can definitely help, but exactly how much blurring you want really depends on the conditions and to some extent, personal preference, not any rule. I don't think there's any way to get it "right" except trial and error in each case, which takes more time than most people want to invest. Honestly, I've seen some drone video on YouTube that followed the 180-rule (often for no good reason because they were flying so high), and to my eye, the blurring just makes them look like they were shot with a crappy lens. Personally, I never use them (I try to avoid flying close to things) because I want my video to be as sharp as possible, mainly because I frequently make panoramas and stereoscopic pairs from video.
 
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When I'm feeling curmudgeonly (like now), I like to point out that, mathematically, the 180 rule means a shutter speed of half the frame rate, not twice…
…It's an arbitrary rule, which supposedly make video more "cinematic" because that's what film cameras do, but it's not magic.

…exactly how much blurring you want really depends on the conditions and to some extent, personal preference, not any rule.

…(no NDs) mainly because I frequently make panoramas and stereoscopic pairs from video.
I very much agree. After my first dozen years in the classroom fighting this terminology battle I gave up - everyone who has ever spoken up (hundreds of students) has said “double”, referring to the denominator of the shutter speed fraction. Decimal units might make it easier?

The reason I make this comment is because it also illustrates something about the “180-rule”. It’s not a rule. It’s a convention. If you want conventional motion blur this is how you get it.

It reminds me of 24p madness. 24p is regarded as more filmic, more cinematic - more accurately, it conforms more closely to the conventions of film. There are plenty of reasons to shoot 30p, or 60, or 120.

If it looks good it is good is a rule I try to support and follow!

On the other hand, in the learning communities I’m involved in (pre-professional) it’s important for learners to know all this stuff cold and to be able to defend why they may have departed from such a convention, (the “motivation” for the treatment in film-speak).

@RogerDH I’d love to hear more about video-based panos and stereo pairs! Maybe that’s another thread, or perhaps you’ve posted before and I’ve missed it.
 
@RogerDH I’d love to hear more about video-based panos and stereo pairs! Maybe that’s another thread, or perhaps you’ve posted before and I’ve missed it.
Microsoft ICE (Image Composite Editor) is freeware (although a little hard to find now that MS doesn't support it) that can make panoramas directly from a selected section of a video. If you have a section of video that pans sideways or up-and-down or S-curves, ICE typical can usually figure out the motion and automatically take frame grabs to make a panorama, and it does a pretty good job. It can also composite individual images from photos or frame grabs, so I also use it for panoramas from DSLR photos, and it's (usually) as good as any panorama software I've seen. (Sometimes I resort to Hugin, but not unless I have to -- too complicated, but that's the price of more power.)

For stereo pairs, I just get frame grabs a little horizontal distance apart and process them through StereoPhoto Maker, which is also freeware. It does a fantastic job of aligning stereo pairs, including size adjustment, X/Y placement, rotation, perspective, and even color-balance differences.
 
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Thanks for the hints about panos & stereo pairs from video @RogerDH! I'm somewhat familiar with panos, ICE and with stereography, but never thought about pulling images out of video - this is great!

***motion blur in drone footage - what does it look like?***
I was reviewing some content this morning and came across this, one of the best internet-sourced examples of what motion blur or the lack thereof can look like. It's just a few seconds in a longer video:
The first example is without an ND filter in daylight, so, one assumes a very short shutter speed (1/1000th?).
The second example is with an ND filter.

So, neither is really right or wrong, it's more about the visual aesthetic of motion one wishes in a shot or project.
 
...

So, neither is really right or wrong, it's more about the visual aesthetic of motion one wishes in a shot or project.
It seems that some people are more susceptible to the "strobing" effect of sharply focused frames: I only see it occasionally (like in your example), but some people see it (or claim to) in just about any video with motion. The best examples I've seen of ND filters noticeable improving video are ones where you have some action, such as people walking or cars going by, that's motion-blurred against a static background that stays in focus. That's why videographers who shoot movies or commercials are justifiably keen on ND filters. IMO, it's the same with drone videos: The smoothing is most noticeable when a very close object is getting a lot of blur, but there's a background that's still in reasonable focus. ND filters are great for that, but I don't typically fly like that, and if I do, I just tolerate the lack of smoothness as a trade-off for sharpness.
 

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