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FOV (Field of View) Issue
2588 20 2017-10-22
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Edd_88
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Hong Kong
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I recently bought a Spark and did a few test shots. I notice that the FOV is much wider in photo than video. Anyone know why or do I have option to choose the view angle?
2017-10-22
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Gunship9
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United States
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Photo is at 12mp.  Video is not that large an amount of detail if you figure for each frame in the movie.  

Video is only 1080p.  I speculate that it is due to the processor not being able to handle 4k video data.  The sensor can give you 4k (technically) but Spark can't handle it.  
2017-10-22
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tedder
lvl.2
Flight distance : 91499 ft
United States
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I assume there is some digital IS on the video side.
2017-10-22
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DJI Thor
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Flight distance : 13599 ft
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The FOV for Spark is 81.9°, it can not be changed. The image size will be adjusted automatically in different modes, see specs below, but the video resolution is permanent 1920×1080. So there is no option for changing the size or resolution manually.
Normal: 3968×2976
1440×1080 with ShallowFocus
2300×1280 with Pano (horizontal)
960×1280 with Pano (vertical)
2017-10-24
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Sparky_17
Captain
Flight distance : 62333 ft
Canada
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Thanks DJI Thor for sharing this info
2017-10-24
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Edd_88
lvl.4
Hong Kong
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I suppose FOV and resolution are 2 separate thing and may not have direct relationship. I use my photo camera (Nikon full frame) to take picture and video. As long as I use the same lens, I got almost the same fov for 7000 x 5000 photo and 1920 x 1080 video. I also did some browsing and believe that dji used some fov for digital IS to compensate the lacking of yaw axial gimbal.
2017-10-26
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JohnRaggio
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Flight distance : 30786 ft
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DJI Thor Posted at 2017-10-24 04:54
The FOV for Spark is 81.9°, it can not be changed. The image size will be adjusted automatically in different modes, see specs below, but the video resolution is permanent 1920×1080. So there is no option for changing the size or resolution manually.
Normal: 3968×2976
1440×1080 with ShallowFocus

When we say that the FOV is 81.9, is that horizontal or diagonal?  I'm actually curious to know the vertical FOV as I am trying to figure out how high I need to fly to capture the top of a building.  I assumed that I could half the vertical FOV and do some trig calculations based on my horizontal distance from the building and my proposed height.  Is this sound?
2018-2-15
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DJT_MVSP
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Flight distance : 2018125 ft
Singapore
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The actual sensor in the spark is 4:3
Photos shot in 4:3 utilize the full sensor
Videos however are 16:9 which means it is Cropped
And with the addition of digital stabilization, it get Cropped even more...
2018-2-16
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motopa
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https://forum.dji.com/thread-135132-1-1.html

it's a big issue
2018-2-16
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AdeP
First Officer
Flight distance : 46940 ft
Netherlands
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Not a big issue but a simple fact
2018-2-16
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Bing Err
Captain
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United States
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Does anyone know if the Mavic Air has the same view for video and photo. It's one of my biggest pet-peeves with the Spark. Did the Mavic Air fix this issue?
2018-2-16
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Aeromirage
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JohnRaggio Posted at 2018-2-15 19:06
When we say that the FOV is 81.9, is that horizontal or diagonal?  I'm actually curious to know the vertical FOV as I am trying to figure out how high I need to fly to capture the top of a building.  I assumed that I could half the vertical FOV and do some trig calculations based on my horizontal distance from the building and my proposed height.  Is this sound?

FOV is Horizontal.
To get a tall building use 3 shot Vertical pano mode.
Like this:



9.jpg
2018-2-16
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JohnRaggio
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Flight distance : 30786 ft
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Aeromirage Posted at 2018-2-16 20:28
FOV is Horizontal.
To get a tall building use 3 shot Vertical pano mode.
Like this:

Thanks. Great shot. My plan is to do 46 shot spherical pano, but want top of 50 story building in the shot. I got up to over 200ft altitude and chickened out once I saw copters in the area. Safety over getting the shot.
2018-2-20
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KREMi
First Officer
Poland
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sparkcutimage.jpg
edit - did update picture, but forum won't let me delete old one :/
hope this helps - but it's just a estimation (based on comparing spark photo/video) -  what area gets cut on spark.
You can do it Yourself - compare vid from one link and photos from other movie



2018-2-20
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RobertWSimpson
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This is very interesting.  I had originally assumed that they were trying to use the native resolution of the sensor to capture video and stills, which would mean a different crop of what the sensor is actually seeing.  
2018-2-20
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KREMi
First Officer
Poland
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just for curiosity, did same for air - and it's quite interesting - 4k/30 and FHD/30 see same, 2,7k60 is croped more, have to check what happen with FHD/120 on weekend
2018-2-20
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JohnRaggio
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Flight distance : 30786 ft
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DJI Thor Posted at 2017-10-24 04:54
The FOV for Spark is 81.9°, it can not be changed. The image size will be adjusted automatically in different modes, see specs below, but the video resolution is permanent 1920×1080. So there is no option for changing the size or resolution manually.
Normal: 3968×2976
1440×1080 with ShallowFocus

The FOV of the lens cannot be changed.  That is true as it's simple physics, but if video mode crops significantly, as it does according to observations and tests below in the thread, then the effective FOV is reduced, given the same subject to camera distance.  in other words, we would need to move back much further in video mode to capture the same frame.  Any idea what the effective FOV might be?  I have to exercise all of my memory of HS math to figure it out.  It's certainly less than 81.9 due to the cropping., no?
2018-2-21
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JohnRaggio
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Flight distance : 30786 ft
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DJT_MVSP Posted at 2018-2-16 03:18
The actual sensor in the spark is 4:3
Photos shot in 4:3 utilize the full sensor
Videos however are 16:9 which means it is Cropped [view_image]

Aspect ratio definitely comes into play as shown in post #14, but as you mentioned stabilization will not only crop the top and bottom, but the sides as well.  I'm trying to figure out how I might calculate the effective FOV given the cropping. (assuming subject distance does not change.
2018-2-21
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JohnRaggio
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Flight distance : 30786 ft
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KREMi Posted at 2018-2-20 13:17
[view_image][view_image]
edit - did update picture, but forum won't let me delete old one :/
hope this helps - but it's just a estimation (based on comparing spark photo/video) -  what area gets cut on spark.

Thanks for taking the time to post these.  Looks like we are "losing" like half of the FOV in video compared to stills.  This explains why I thought the Air's 17 degrees helped my friend get the top of the building in his shot at a far lower height.  He was shooting stills and I was shooting video!
2018-2-21
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JasonPhotog
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Its because of the resolution. The sensor has a 12mp resolution. Essentially 4000 by 3000 pixels. In order to make that into 1080p, they take the center 1920x1080 pixels and then blow them up to use up the most amount of space on the sensor (if they simply used 1920x1080 pixels, they would effectively gather about 1/4 of the light which would not be good) so they take the 1920x1080 and do some math to make groups of original pixels into "larger pixels" that make up the correct number for HD1080p (and they may even be using groups of pixels to change the aspect ratio. If the pixels are square shaped, for example, they would maybe use 3 pixels wide by 2 pixels tall to make one HD pixel, but that is way beyond my actual comprehension)

The end result here ends up being a bit of a crop from the full field of view for the photograph. Im not sure what the end FOV is but it kind of looks similar to 35mm on a full frame dslr. Technically, the original field of view from the photograph can be maintained but it would have to loose some top and bottom to fit into 16x9 and then it has to be processed from 12mp down to a little more than 2mp in real time at 30 frames per second. This is probably too much math for the machine to handle. It is, after all, a very inexpensive camera drone. You dont get all the bells and whistles at this price point.
2018-7-21
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N Theogen
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United Kingdom
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JohnRaggio Posted at 2018-2-21 13:30
The FOV of the lens cannot be changed.  That is true as it's simple physics, but if video mode crops significantly, as it does according to observations and tests below in the thread, then the effective FOV is reduced, given the same subject to camera distance.  in other words, we would need to move back much further in video mode to capture the same frame.  Any idea what the effective FOV might be?  I have to exercise all of my memory of HS math to figure it out.  It's certainly less than 81.9 due to the cropping., no?

I've been pondering this from the perspective of creating mosaic maps (flying a grid pattern, taking pics).
and calculating overlaps

My back of a fag packet calculations say  -
89.1 FOV is close to a right angle. Close enough to say that  at 100 meters alt your Spark camera will capture about 200m L-R and 150m T-B (4:3!) , pointing straight down, which, of course, it can't.


6-28 02:55
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