Why is detail lacking in this video?

Consultant · Mar 5, 2017

This video was shot in 4K 30fps with a Phantom 4. Granted the lighting that day was not good (the original footage looked way darker than this - this is corrected footage using Davinci Resolve with most settings turned up considerably - but the detail is the same as the original footage.) However in both this and the original footage, the details in the beach ground and trees near the house are almost non-existent, it looks very blurry. My partner shot this video so I'm not sure the exact settings used.

This was a fly by with pan but it was done pretty slowly. An ND filter may have been used so maybe that's a contributor Here's the file info from the original footage.

Here's the actual original, uncorrected footage:
Here's the file info:

General
Complete name : D:\Temp\Downloads\DJI_0016flybywithPOI.MOV
Format : MPEG-4
Format profile : QuickTime
Codec ID : qt 2014.02 (qt )
File size : 190 MiB
Duration : 26 s 860 ms
Overall bit rate mode : Variable
Overall bit rate : 59.2 Mb/s
Encoded date : UTC 2017-02-25 07:40:18
Tagged date : UTC 2017-02-25 07:40:18
Comment : 0.91.142M
©xyz : +47.406590-122.936082+13.800
©xsp : -2.10
©ysp : -3.20
©zsp : +0.00
©fpt : +12.30
©fyw : -119.70
©frl : -1.40
©gpt : -18.00
©gyw : -119.00
©grl : +0.00

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : [email protected]
Format settings, CABAC : Yes
Format settings, ReFrames : 1 frame
Format settings, GOP : M=1, N=8
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 26 s 860 ms
Bit rate mode : Variable
Bit rate : 59.2 Mb/s
Maximum bit rate : 60.0 Mb/s
Width : 3 840 pixels
Height : 2 160 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 29.970 (30000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.238
Stream size : 189 MiB (100%)
Title : DJI.AVC
Language : English
Encoded date : UTC 2017-02-25 07:40:18
Tagged date : UTC 2017-02-25 07:40:18
Color range : Limited
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709

ChiefStealth · Mar 5, 2017

The Phantom cameras have a rather high FOV. Very wide angle. You have to get pretty close to the subject to get good detail. You should not expect high detail if you do your filming from distance.

Nickster · Mar 5, 2017

@Consultant, what sd card were you using? That may be one problem. You need a fast writing card for 4k. Also, the panning is quick on the video. Just work with it and slow it down some. That will help. For the focus, set your focus by tapping what you want to make sure is the main focus of the shot.

Mr. Salty · Mar 5, 2017

I think the serious underexposure contributed a lot to your problem.

Consultant · Mar 5, 2017

Nickster said:
@Consultant, what sd card were you using? That may be one problem. You need a fast writing card for 4k. Also, the panning is quick on the video. Just work with it and slow it down some. That will help. For the focus, set your focus by tapping what you want to make sure is the main focus of the shot.

The panning isn't quick when you get more right in front of the house which is where the still frame I posted is from which you can see in the still frame is very blurry on the beach ground and trees near the house.

Are you serious regarding the SD card? Digital video is just a bunch of numbers. Either the camera can write the numbers to the file on the card or it can't. If the SD card effected the video quality, that would have to mean that the bitrate and framerate information in the video is BOGUS! This shot has 60,000 kpbs bitrate and 30fps framerate. During the slow pan right in front of the house, the details on a 4K shot should be excellent in my opinion.

I can't remember all the settings on the camera as I didn't shoot this, a business partner of mine did. If I recall, you can't set a shutter speed on video shooting on a P4, right? But in the photography world the blur would be a result of too low of a shutter speed (not a slow SD card). The exposure, aperture, and ISO settings are going to effect the shutter speed. Can you control ISO setting for video on a P4? If so, I'm guessing the ISO was too low, combined with the low lighting (and possibly and ND filter), resulted in too slow of a shutter speed - hence the blur even with slow movement.

If you can provide a more technical in-depth explanation of how an SD card speed can effect image quality in a video, I'd love to hear it because I can't for the life of me (being a Software Engineer) think of any reason why, especially considering the camera uses a memory cache. If the card is too slow, and you ran out of cache, the camera would fail all together trying to write to the card. What exactly are you saying is happening due to the card being too slow that would effect the resolution/detail. Here's the actual playback info:

Consultant · Mar 5, 2017

Mr. Salty said:
I think the serious underexposure contributed a lot to your problem.

This sounds like more of a plausible explanation. Generally, the advice though is to underexpose rather than overexpose (not that this was underexposed on purpose) since you can fix underexposure easier than overexposure. If it's blown out, you aren't getting any detail back. But I guess what you are saying here is that this is so underexposed, much of the detail got lost in pure black which like pure white, you can't get the detail back. Correct?

Nickster · Mar 5, 2017

Consultant said:
The panning isn't quick when you get more right in front of the house which is where the still frame I posted is from which you can see in the still frame is very blurry on the beach ground and trees near the house.

Are you serious regarding the SD card? Digital video is just a bunch of numbers. Either the camera can write the numbers to the file on the card or it can't. If the SD card effected the video quality, that would have to mean that the bitrate and framerate information in the video is BOGUS! This shot has 60,000 kpbs bitrate and 30fps framerate. During the slow pan right in front of the house, the details on a 4K shot should be excellent in my opinion.

I can't remember all the settings on the camera as I didn't shoot this, a business partner of mine did. If I recall, you can't set a shutter speed on video shooting on a P4, right? But in the photography world the blur would be a result of too low of a shutter speed (not a slow SD card). The exposure, aperture, and ISO settings are going to effect the shutter speed. Can you control ISO setting for video on a P4? If so, I'm guessing the ISO was too low, combined with the low lighting (and possibly and ND filter), resulted in too slow of a shutter speed - hence the blur even with slow movement.

If you can provide a more technical in-depth explanation of how an SD card speed can effect image quality in a video, I'd love to hear it because I can't for the life of me (being a Software Engineer) think of any reason why, especially considering the camera uses a memory cache. If the card is too slow, and you ran out of cache, the camera would fail all together trying to write to the card. What exactly are you saying is happening due to the card being too slow that would effect the resolution/detail. Here's the actual playback info:

You are right with the shutter speed. I did not think of that. You can adjust it in the setting for video. 2x frame rate is recommended to reduce blur. As for SD card, I have seen a difference if it is slower than 80Mb/sec and not Class 3. I hope that helps.

Consultant · Mar 5, 2017

How would I go about finding what the ISO and Shutter Speed settings were for the shot? Doesn't look like it is in the file info? (Phantom 4)

ryantrax · Mar 5, 2017

I would have to agree with underexposure causing this. What was your exposure compensation set to? A common mistake is rolling the right thumb wheel up or down increases or decreases your exposure compensation, I'm guessing it was set at a negative number (-.3, -.5 or greater)

Nickster · Mar 5, 2017

Consultant said:
How would I go about finding what the ISO and Shutter Speed settings were for the shot? Doesn't look like it is in the file info? (Phantom 4)

It is in the camera settings under the button on the right of the screen. You can adjust them on the 1st menu in that. It will be on auto to start. You can switch to manual and force it to the correct settings.

Consultant · Mar 5, 2017

Nickster said:
It is in the camera settings under the button on the right of the screen. You can adjust them on the 1st menu in that. It will be on auto to start. You can switch to manual and force it to the correct settings.

I mean how do you find out what the settings WERE (past tense) for any particular video clip shot with the P4?

Mr. Salty · Mar 5, 2017

Consultant said:
This sounds like more of a plausible explanation. Generally, the advice though is to underexpose rather than overexpose (not that this was underexposed on purpose) since you can fix underexposure easier than overexposure. If it's blown out, you aren't getting any detail back. But I guess what you are saying here is that this is so underexposed, much of the detail got lost in pure black which like pure white, you can't get the detail back. Correct?

You're right, it's better to underexpose a bit than overexpose. But there are limits. The original video above is underexposed by several stops. It's just so dark it's going to be lacking detail to restore. I'm amazed it looks as good as it does.

I'm currently working on some photos I shot with my P3S of the Iowa Statehouse. The best ones are slightly underexposed because they preserve detail in the gold dome, which reflects a lot of light. But even underexposed a stop or two they're way, way lighter than that video.

Mr. Salty · Mar 6, 2017

Consultant said:
I mean how do you find out what the settings WERE (past tense) for any particular video clip shot with the P4?

I don't know whether video files contain that kind of data or not. I'll have to look at some of my original files later when I get home.

But I can almost guarantee you that, generally speaking, the video was shot with the exposure set to manual and then it wasn't adjusted. If it looks like that with the camera set to auto you've got a problem with the camera.

I can't believe the person who flew the mission didn't realize there was a problem, because what he would have been seeing on the screen would have been so dark.

I disagree that the microSD card had anything to do with it. The quality (write speed) of the card is important, but if that were the issue the camera simply wouldn't have been able to keep up with recording and you'd have footage that stuttered and froze. It wouldn't be perfectly smooth but underexposed.