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Old Feb 07, 2011, 06:58 AM
jhi
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Quote:
Originally Posted by 120ccpm View Post
Hi guys, thanks for the excellent thread, lots of info.

...
- AOV is a bit less than 52 degrees, so not quite at 58 as reported here on post 314, but closer to the 54 reported on post 1343
...
I think that there is some confusion here about AOV. Have a look at post 314 again - Tom Frank stated that "it would take a 58.2 deg. AOV to capture the corner-to-corner image of his video". If you take my horizontal measurements (bottom of message), width=810mm and distance=835mm, you arrive at 51.75.

/Jan
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Last edited by jhi; Feb 07, 2011 at 07:29 AM. Reason: Typos
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Old Feb 07, 2011, 07:25 AM
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Quote:
Originally Posted by jhi View Post
I think that there is some confusion here about AOV. Hava a look at post 314 again - Tom Frank stated that "it would take a 58.2 deg. AOV to capture the corner-to-corner image of his video". If you take my measurement (bottom of message) width 810mm and distance 835mm you arrive at 51.75 degrees.
Yes, I'm not sure where the 58.2 comes from, maybe Tom was talking about the diagonal AOV, as he says "corner-to-corner", while you and I are referring to the horizontal AOV (and we arrive at the same numbers: 51.75 for you, 51.74 for me).
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Old Feb 07, 2011, 07:42 AM
jhi
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Quote:
Originally Posted by 120ccpm View Post
Yes, I'm not sure where the 58.2 comes from, maybe Tom was talking about the diagonal AOV, as he says "corner-to-corner", while you and I are referring to the horizontal AOV (and we arrive at the same numbers: 51.75 for you, 51.74 for me).
I probably should let Tom Frank answer this himself to avoid more confusion , but I can see he combined both the width 810mm and height 455mm measurements with distance 835mm to arrive at the correct diagonal AOV 58.2.

/Jan
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Old Feb 07, 2011, 08:17 AM
Just thumbing through...
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United States, SC, Simpsonville
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Sounds like all are correct. There's a table here about 2/3 down which shows horizontal, vertical and diagonal, and the 35mm film lens equivalent. The exact formula for the 35mm conversion is on Chuck's page
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Old Feb 07, 2011, 08:23 AM
Just thumbing through...
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United States, SC, Simpsonville
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Quote:
Originally Posted by 120ccpm View Post
Is there a way to sort of "average" saturation, during post-processing?
Some software has "auto-level" video filter that might help. Probably best to convert to MJPEG first.
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Old Feb 07, 2011, 10:30 AM
Dance the skies...
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United States, MA, Walpole
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Quote:
Originally Posted by victapilot View Post
Sounds like all are correct. There's a table here about 2/3 down which shows horizontal, vertical and diagonal, and the 35mm film lens equivalent. The exact formula for the 35mm conversion is on Chuck's page
Looks like this has been sorted out. I was interested in corner-to-corner AOV to diminish the vignetting if a suitable replacement lens could be found.
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Old Feb 07, 2011, 10:41 AM
Dance the skies...
Tom Frank's Avatar
United States, MA, Walpole
Joined Dec 2003
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Quote:
Originally Posted by victapilot View Post
Some software has "auto-level" video filter that might help. Probably best to convert to MJPEG first.
One of the color filters in AviDemux has an auto-white level toggle. I tried it on one clip, and it looked like it might have helped a small amount, but I didn't combine before/after images side by side to compare. It certainly did not eliminate the "hunting" this camera does. But I also did not first output to MJPEG... don't know if that would make a difference... I thought each frame was fully reconstructed before any of the filter action was applied. WHen I get my replacement camera, I will experiment with this more. I also want to try that vignetting correction filter that VDub has.
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Old Feb 07, 2011, 10:59 AM
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Bangkok
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Quote:
Originally Posted by 120ccpm View Post
Hi guys, thanks for the excellent thread, lots of info.

I got the HD720 camera from eBay seller hxelepro360, took only 9 days to arrive to Switzerland. A couple notes:
- firmware update to remove timestamp worked without issues
- focus range was acceptable, I won't mess with it
- AOV is a bit less than 52 degrees, so not quite at 58 as reported here on post 314, but closer to the 54 reported on post 1343
- Bitrate is 10.8Mbps

On the negative side, the camera struggles with color saturation, not much because it's too high or too low on average, but because it fluctuates a lot, you can see the camera chasing the right balance every time there's a small change in the light conditions. Check the attached snapshots, taken few seconds apart with the heli in stable hover: all it takes is a slight change in the amount of light (heli pointing a bit more toward the sky) and saturation increases significantly.

Is there a way to sort of "average" saturation, during post-processing?





The non HD keychain camera suffers from the same, it's a losing battle to try to edit the colours to get an even look, even with professional video editing software (we have After Effects at work, also Premiere and Nuke, but I haven't got around trying them)
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Old Feb 07, 2011, 11:04 AM
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Tom, since you seem to have a direct connection to the manufacturer, I think it could be worth mentioning this "hunting effect"...
I'm not an expert, but by simple observation it appears that this camera is trying too hard to adjust saturation, going from one extreme to another: maybe I'm totally off, but reducing the available range might give better results.

I know we ask a lot for $40...
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Old Feb 07, 2011, 11:37 AM
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Hello, just got mines from Eletoponline. Both have a red lens. Didn't have time to check further yet. They seem to work.
One question tho: is there a special way to format the SD? One of the Micro SD 4Go class 4 (no name) I got simply doesn't work on both camera. Is it just not good enough?
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Old Feb 07, 2011, 11:39 AM
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Sofia, Bulgaria
Joined Jan 2011
41 Posts
I ordered another camera and I contacted my seller (eletoponline365) again:
Quote:
Hello friend.
I hope, that you have had great and happy holidays.
I ordered another camera from you. This time I insist to have test and send me real videos made especially with my future camera, I don't wаnt to get another bad camera with focus malfunction. I will send my payment for the camera as soon as you send me that videos.
Thanks for your understanding.
Svilen.
And now, I'm waiting...
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Old Feb 07, 2011, 01:23 PM
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France
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hey thanks to this thread i received mine today i am really happy with it , cant wait to put it on the plane , i hope some one will get AV/out of this thing
darkside of the dog . (0 min 6 sec)
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Old Feb 07, 2011, 02:05 PM
Just thumbing through...
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United States, SC, Simpsonville
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Quote:
Originally Posted by Tom Frank View Post
Looks like this has been sorted out. I was interested in corner-to-corner AOV to diminish the vignetting if a suitable replacement lens could be found.
I finally got around to measuring the lens assembly diameter for my venerable #3, it's only 5.4mm. The lens itself is big, but no joy for a HD808 swap
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Old Feb 07, 2011, 08:44 PM
Must not buy more planes!
mclarkson's Avatar
USA, KS, Wichita
Joined Jul 2010
2,347 Posts
Some footage from a quick flight with mine:
Radian Glider doing Loops (2 min 14 sec)


I am getting a big difference in color balance between the center of the image and the border, as well as some visible vignetting. I'm attaching a screen grab of what should be a fairly homogeneous landscape. It was a mostly cloudly/overcast day, so the lighting is pretty even.

When you look at samples from different areas in the frame, however, there's a big difference. I'm also seeing a difference is sharpness between the center and the rest of the frame.
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Old Feb 07, 2011, 08:53 PM
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Canton, Michigan USA
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I think back a few years and all you had was one of these with something like 320 by 280 resolution and it cost $75. We certainly want a lot out of a $40 HD camera the size of key fob:
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Last edited by Prof100; Feb 07, 2011 at 09:15 PM.
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