Hugely underexposed in desert with ND8 on auto expose. How did this happen?

[Mr. Salty]

Have you read the info on mediacollege.com I posted at all?

I have, and you're misinterpreting what it says. I've been shooting and editing film for longer than Qoncussion has and he's 100 percent correct.

The "gap" referred to in the mediacollege link you posted is to a gap in time between when frames are captured, not a physical black gap recorded in the video as you wrote above. To quote: "Think of the "missing time" as a gap between when the shutter closes and when the next frame begins."

All you have to do is watch video frame by frame. You won't find any black gaps.

 

[Lee Snook]

My preference is to turn On Over Exposure warning in the camera settings.
This will overlay Zebra Stripes in over exposed areas of the image viewed on the monitor when flying.
Adjust the right thumbwheel so that the sky or brightest areas show some zebra stripes.
If you are flying in different directions relative to the sun, you may have to constantly readjust the exposure thumbwheel
when turning to a new direction.
In very high contrast situations, you may have to overexpose to bring out detail in the shadows.

 

[M3d4r]

Again, I don't want to debate about stuff that is open for any opinion. You keep talking about my opinion, but it just pure fact.
I edited celluloid film with hand wound viewers many years ago. Turning the wheel slow (slow frame rate), one could see a strobe effect, while turning it fast (fast frame rate) it would be fluid. Hence the gaps between the frames were to small to be noticed. Now if the frame time (slow frame rate, turning the wheel slowly) is longer than the shutter speed, there's a relatively big gap until the next frame begins. Hence even bigger strobe effect with lower speeds(frame rate). Simple. You say all you want, but that doesn't change it.

A higher frame rate allows for faster shutter speeds....again, simple once you get your head around the basics.

The way you say it defies the science of filming. You made it up yourself. Again, show me your proof. Show me one website with reputation that confirms your theory. Please. People could get confused reading this discussion.

Have you read the info on mediacollege.com I posted at all?

Frame rate and shutter speed on a digital camera are not the same as on celluloid tho. Celluloid has physical gaps between one frame and the other which show as black. The single frame is still fully exposed to light it’s a property of the celluloid film that has the black.

A digital camera such as the one on your mavic simply has no black spaces between frames it just renders them slower depending on frame rate. Which is technically just render speed of the entire image.

 

[Qoncussion]

Again, I don't want to debate about stuff that is open for any opinion. You keep talking about my opinion, but it just pure fact.
I edited celluloid film with hand wound viewers many years ago. Turning the wheel slow (slow frame rate), one could see a strobe effect, while turning it fast (fast frame rate) it would be fluid. Hence the gaps between the frames were to small to be noticed. Now if the frame time (slow frame rate, turning the wheel slowly) is longer than the shutter speed, there's a relatively big gap until the next frame begins. Hence even bigger strobe effect with lower speeds(frame rate). Simple. You say all you want, but that doesn't change it.

A higher frame rate allows for faster shutter speeds....again, simple once you get your head around the basics.

The way you say it defies the science of filming. You made it up yourself. Again, show me your proof. Show me one website with reputation that confirms your theory. Please. People could get confused reading this discussion.

Have you read the info on mediacollege.com I posted at all?

I'm afraid you have incomplete knowledge of how video is captured. Saying that I made anything up, or that I am stating my opinion are both plain wrong. And I beg your forgiveness ~ as I'm not going to prove it to you.

Your quote:
"Think of the "missing time" as a gap between when the shutter closes and when the next frame begins."

^^ Exactly correct. The first frame, in this example was exposed to an image, only for the amount of time required to get the proper exposure. The shutter will trigger again at the start of the next frame, but that doesn't mean that the frames are incomplete - just that the proper exposure was applied and the shutter closed, so as not to over expose the frame. A closed shutter does not equal a black frame ~ in this case it equals a completed frame at the proper exposure.

I totally agree that higher shutter speeds lend themselves to a choppy looking clip when shooting motion (either the camera in motion or the subject in motion - or both), as each video frame is only exposed for a fraction of the time that frame actual appears on screen - but *the entire frame is filled* with whatever image was captured in the brief split second that the shutter was open.

Even the rule of 180 has the shutter closed for half of each frame. I will absolutely stand by the statement that there are no sections of black recorded on digital video due to any type of mismatch between the frame rate and the shutter speed.

 

[Plawa]

Following LF's (faulty) logic anything with exposure time shorter than 1/fps would have gaps. And yet, I can show you a PowerPoint presentation with photos taken at 1/8000s, flip 1 slide every 5 seconds and there will still be no black gaps.. granted it won't be the smoothest video ever but you get my point (I'd hope).

Frame capture time <> display time.

 

[Qoncussion]

since you insist,
exactly

You have much to learn...

 

[Qoncussion]

The way you say it defies the science of filming.

I think you misspelled "defines"...

You made it up yourself.

That's a pretty hardcore comment, coming from someone whose imagination has them believing, and posting nonsense about black frames that don't exist.

People could get confused reading this discussion.

I agree! Once you have an understanding of what you are unabashedly talking about, feel free to correct yourself to avoid any [more] confusion.

It is clear that you are not understanding the differences between frame rate and shutter speed. Believing that video flicker is the result of partially black frames is something that you should reconsider spreading about - to avoid any future confusion.

Sorry man, but your attitude, knowledge of the subject and general method of communication just stink.

My apologies to the OP for this tangent!

 

[truckstop]

I have, and you're misinterpreting what it says. I've been shooting and editing film for longer than Qoncussion has and he's 100 percent correct.

The "gap" referred to in the mediacollege link you posted is to a gap in time between when frames are captured, not a physical black gap recorded in the video as you wrote above. To quote: "Think of the "missing time" as a gap between when the shutter closes and when the next frame begins."

All you have to do is watch video frame by frame. You won't find any black gaps.

While this is correct - there is no "black" between frames on high shutter speed video, it can lead to strobing. This would be especially evident with say, a static shot that has a bird flying through it. At a lower shutter speed - say 1/60th, the bird's motion across the frame would be fluid. But, at a higher shutter speed, the bird will jump across the frame, as it will move during the "missing time" described in the quote above. Ideally, if you really want things to look cinematic, you want to go for a shutter speed as close to 2x your frame rate as possible - i.e. 1/50th for 24fps.

 

[truckstop]

Frame rate and shutter speed on a digital camera are not the same as on celluloid tho. Celluloid has physical gaps between one frame and the other which show as black. The single frame is still fully exposed to light it’s a property of the celluloid film that has the black.

A digital camera such as the one on your mavic simply has no black spaces between frames it just renders them slower depending on frame rate. Which is technically just render speed of the entire image.

This is *almost* correct. Celluloid does not have physical gaps between frames (well, I suppose you could argue that a 2:35 aspect ratio image rendered onto a 35mm print might, but that's another story...). Rather, a shutter is closed on the projector while the film is advanced - this is what creates the moment of black between frames when projecting film. Each frame is held static within the projector gate for 1/24th of a second and projected onto the screen. Then the projector shutter closes (black) and the film is advanced to the next frame, the shutter opens, and that frame is projected for 1/24th of a second. And so on. If the film simply ran through the projector without pausing like this, momentarily static, in the gate, you'd just see a non-stop light blur. This process is largely the same when the film is exposed in the film camera.

 

[djiboi]

Exposure is far more important than motion blur. Always get the correct exposure using the EV value or the histogram. ND filters do nothing for quality, they just introduce motion blur for fast moving subjects. If you are filming landscapes, don't bother with them. I tend not to use them at all anymore. If something looks like it could do with some blur, I tend to just add it in post. Time is too short to be messing around with filters....

I know some people will disagree but hey ho, this is just my personal experience rather than what so called experts suggest while trying to sell you then via affiliate links.

Now if I had the time and was producing studio quality footage (which wouldn't be from a mavic anyway) I might have a different opinion.

 

[rickray]

So what I gathered from the very good video posted above about ND filters is that they really aren't very useful for anything apart from shutter speed motion blur on a moving object near the drone. For those of us who want to film landscapes or distant moving objects, the video shows the ND filter really isn't useful.

I started using ND filters to eliminate "jello" effects a long time ago. It now appears this problem has been eliminated on all DJI drones. So I'm not sure they are as useful as I thought.

Like the histogram idea and I'll start using it. Thanks for the insights.

 

[Mavic_Pete]

Just got back from Maui, Hawaii today. Purchased polar pro filters before I went on the trip. Nd 8,16, and 32 all polarized.. it made a huge difference on still pictures and videos. IMO if you think the filters are only good for video you are wrong.

 

[Plawa]

Polarizer yes.. but ND alone will only make your photos more blurry when shooting from a drone.

 

[Mavic_Pete]

Ahhh that makes sense... I was on the fence about only getting 1 polarized and 2 ND but I am very glad I got all 3 polarized. Especially because I live in the always sunny desert (Arizona).

 

[oldcelt]

My two-pennorth as a lifelong photographer (and I'm now an ancient old fellow) :-

The Media College illustration relating FPS and shutter speed is misleading. It gives the impression that the shutter opens immediately the edge of the frame enters the exposure zone. That is not the case.

What happens is that each frame moves into the exposure area and at exactly the moment when it is fully centred then the shutter operates so that the whole frame is exposed. The shutter speed simply affects the time light falls upon the frame and results in a full frame of equal exposure.

The analogy of using a hand wound viewer is not really relevant. That can be slow enough to see the gaps between frames but there are no regular black strips on each frame!

 

[Lake_Flyer]

I'm afraid you have incomplete knowledge of how video is captured. Saying that I made anything up, or that I am stating my opinion are both plain wrong. And I beg your forgiveness ~ as I'm not going to prove it to you.

Your quote:
"Think of the "missing time" as a gap between when the shutter closes and when the next frame begins."

^^ Exactly correct. The first frame, in this example was exposed to an image, only for the amount of time required to get the proper exposure. The shutter will trigger again at the start of the next frame, but that doesn't mean that the frames are incomplete - just that the proper exposure was applied and the shutter closed, so as not to over expose the frame. A closed shutter does not equal a black frame ~ in this case it equals a completed frame at the proper exposure.

I totally agree that higher shutter speeds lend themselves to a choppy looking clip when shooting motion (either the camera in motion or the subject in motion - or both), as each video frame is only exposed for a fraction of the time that frame actual appears on screen - but *the entire frame is filled* with whatever image was captured in the brief split second that the shutter was open.

Even the rule of 180 has the shutter closed for half of each frame. I will absolutely stand by the statement that there are no sections of black recorded on digital video due to any type of mismatch between the frame rate and the shutter speed.

All good.

 

[Lake_Flyer]

The analogy with celluloid film tape was just to make it more visible.
With digital video you don't have gaps. Instead the whole frame is filled with a still. And since the frames are advancing slower than the shutter, it becomes choppy. Because the virtual black gap isn't filled with next shots but just the one. The next frame the object has moved a bit, showing like a very short jump.
But i agree, the black gap analogy is not the right way to explain.

I honestly stand corrected if I understand that the following would be true:

suppose you would have a frame rate of 30 frames/second. With a shutter speed of 1/2000 second, the film doesn't become choppy or even stroboscopic. I would only miss motion blur. This would mean that if I hover static with a slow moving object I would not have any strobe effect.

I'm going to try that out today, it's quite sunny.

 

[Lake_Flyer]

The analogy with celluloid film tape was just to make it more visible.
With digital video you don't have gaps. Instead the whole frame is filled with a still. And since the frames are advancing slower than the shutter, it becomes choppy. Because the virtual black gap isn't filled with next shots but just the one. The next frame the object has moved a bit, showing like a very short jump.
But i agree, the black gap analogy is not the right way to explain.

I honestly stand corrected if I understand that the following would be true:

suppose you would have a frame rate of 30 frames/second. With a shutter speed of 1/2000 second, the film doesn't become choppy or even stroboscopic. I would only miss motion blur. This would mean that if I hover static with a slow moving object I would not have any strobe effect.

I'm going to try that out today, it's quite sunny.

Well I'm not entirely convinced yet. I first had it static on the balcony, without props spinning, I could hardly see any difference indeed even while having 1/3200 at 24fps.

The strobe effect comes when moving the lens or the nose of the aircraft so that every object in view moves, even if very slow. Then it becomes clearly visible, like a very fast stop motion. (which feels like spinning an old film viewer quite fast). Also, on bright days and in some lighting circumstances I often noticed to capture the (very) slight shadow the spinning props cast over the lens, only with too high shutter speeds, sometimes I had a too light ND filter on and was too lazy to change for a darker one. Using a lens hood (I always do) never solved this. Lowering the shutter speed with the proper ND however did. It blurs the prop shadows entirely and at same time, all objects move fluently.
With 1/200 and 100fps it still looks quite fluid even if every still is almost razor sharp, funny.

 

[Lake_Flyer]

Look at this video, at 1/4000 you clearly there's no motion blur at all. If you pause the video you see the object quite sharp. But you do see the flickering I'm talking about.

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[Lake_Flyer]

your attitude, knowledge of the subject and general method of communication just stink.

I'm not the one talking like that. Talking about attitude........