Author Topic: Rolling shutter measurements  (Read 28798 times)

dpjpandone

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Re: Rolling shutter measurements
« Reply #25 on: July 25, 2014, 04:51:00 PM »
Ok. BTW please do not remove this feature for code cleanup, I think it is incredibly useful to display rolling shutter info.

glubber

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Re: Rolling shutter measurements
« Reply #26 on: July 25, 2014, 07:48:21 PM »
EOS 550D

1080-25p


720-50p
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ItsMeLenny

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Re: Rolling shutter measurements
« Reply #27 on: July 26, 2014, 09:42:28 AM »
On a somewhat related note, I've always questioned which is better:
24 fps exact from 25 fps canon
or
24 fps exact from 23.976 fps canon

escho

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Re: Rolling shutter measurements
« Reply #28 on: July 26, 2014, 05:16:39 PM »
The test-results for my 600D:

Code: [Select]
1920/24 normal: 18,8µs/line --> 17,8ms at 1680x944  A: 542(-4)   B:2214(+14)
1928/24 3xzoom: 20,6µs/line --> 20,0ms at 1728x972  A:(592(+20)  B:2027(-73)

1920/25 normal: 19,8µs/line --> 18,7ms at 1680x944  A:570(-6)    B:2021(+71)
1920/25 3xzoom: 19,8µs/line --> 19,2ms at 1728x972  A:570(-6)    B:2021(+71)

1280/50 normal: 20,0µs/line --> 11,4ms at 1280x568  A:576(+0)    B:1000(+0)

640/25 normal:  19,8µs/line --> 9,5ms at  640x480   A:570(-6)    B:2021(+21)

All test h264 and exact fps (Canon default)

More needed? Please tell me.

Edgar
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600D, 6D, openSUSE Tumbleweed

dmilligan

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Re: Rolling shutter measurements
« Reply #29 on: July 26, 2014, 09:56:51 PM »
check this out, 60D 640x480 crop mode (the Canon crop mode):


1080p30 5x Zoom (Photo LV 5x is the same)


1080p30 (Photo LV is the same)


How does it read the sensor faster in 640x480 crop mode?

Greg

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Re: Rolling shutter measurements
« Reply #30 on: July 26, 2014, 11:17:14 PM »
How does it read the sensor faster in 640x480 crop mode?

Sensor probably read less number of lines.

a1ex

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Re: Rolling shutter measurements
« Reply #31 on: July 26, 2014, 11:20:42 PM »
Interesting.

I believe timer A is roughly proportional to horizontal resolution. On 60D, in 5x and 30p, raw resolutions are 2520 and 1888, and timer A values are 734 and 546 (ratio around 3.45). In 640 crop, if this theory is true, we should be able to push timer A down to around 270 (but it doesn't seem to be that simple). FYI, the raw resolution in this crop mode is 920x624.

I've checked the safe timer A values for 60D again, and they are: 536 for full-width modes, 732 for 5x, and 398 for 640 crop. So, the current timer A values from fps-engio.c are correct (with a tiny safety margin); only timer B probably can be pushed a little more in high FPS modes.

In crop mode, the captured area is not centered (it touches either the left or the right edge). Maybe that's an important restriction. If this is true, reading 920 raw pixels from center should be as expensive as reading 1888/2 + 920/2 = 1404 pixels from one edge (well, not very exact, because I didn't consider the black borders - you know, Pi is about 3). But 1404 / 3.45 is too close to 400 to be just a coincidence.

edit: myth debunked - the 60D has 3 horizontal positions for the 5x zoom window...

ayshih

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Re: Rolling shutter measurements
« Reply #32 on: July 27, 2014, 12:48:54 AM »
50D rolling shutter time is 24–26 ms, with only a small room for improvement by minimizing timer A.

Default timer A (zoom on right):


Minimized timer A (zoom on right):

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budafilms

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Re: Rolling shutter measurements
« Reply #33 on: July 27, 2014, 06:22:29 AM »
On a somewhat related note, I've always questioned which is better:
24 fps exact from 25 fps canon
or
24 fps exact from 23.976 fps canon

24/25 from Canon Menu.

escho

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Re: Rolling shutter measurements
« Reply #34 on: July 27, 2014, 07:02:59 AM »
added timers to my 600D-table
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jimmyD30

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Re: Rolling shutter measurements
« Reply #35 on: July 28, 2014, 01:49:46 AM »
Came across these articles, they mention Canon 5D Mark III and Panasonic GH4 as well as others.

Rolling Shutter Comparison: http://www.cinema5d.com/rolling-shutter-sony-a7s-vs-arri-amira-canon-c300-5d-mark-iii-1dc-panasonic-gh4/

And here: http://nofilmschool.com/2014/07/rolling-shutter-how-does-sony-a7s-compare/

2blackbar

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Re: Rolling shutter measurements
« Reply #36 on: July 28, 2014, 05:03:08 PM »
Yep, makes sense.

However, the EOS-M has a quirk: in standby, its LiveView is in 50/60 fps mode IIRC. Can you double-check the numbers while recording H.264?
I checked during recording in 23.976 override and it said 15.9 ms in 1728x972, lowest i could get by modifying A timer was 15.8 then i checked crop mode and its also the same values, just resolution is 971 instead of 972.
It would be nice to use  improved rolling shutter settings in 23.976 and most canon default framerates with and sound enabled during h.264 recording.