Measuring rolling shutter: put a number on this issue!

[john flores]

Good work, gentsM

[Samuel H]

I just added the results for the BlackMagic Pocket Cinema Camera: very impressive, at 17.8ms

Even so, there are lots of complaints around about the awful rolling shutter in that camera. My guess is that this is caused by the size and weight: it is so tiny that it will move around a lot more unless you add weight or treat it very gently.

[Samuel H]

Just added: Sony RX10.
It's the fastest rolling shutter I've measured so far, at 14.8 ms, right in expensive-camera territory. Thanks to Wesley Byram for sending me the clip to measure this.

[aldolega]

Someone please measure the GH4 in 1080, VFR, and 4K modes!

[Samuel H]

I'd definitely be interested in those numbers. The GH4 and the a7s are the hottest cameras right now, and only one of them is in the hands of users. Haven't had luck asking for this in the GH4 subforum, though.

[c3hammer]

Are you guys getting radically different numbers between 24p and 60p on a cam? My G6 is giving 15.15 in 24p but only 5-6 in 60p. I've been through the calculations a dozen times and 60p is always a much lower number. Surely sensor read out has nothing to do with frame rate?

[Samuel H]

The measurements I took are all at 24p. In some cameras (for example my NEX-5N), it does change with frame rate, because a lower portion of the sensor is read at higher fps, and this makes read-out times faster.

[storyteller]

Great work guys! Probably would help to have several independent tests of each camera. Also, any way to have one, consolidated, running list?

[Samuel H]

I'm not sure we would gain anything by having more than one person testing each camera: I designed the test to average out all inconsistencies and give out an objective, quantitative measure. But if you are not convinced and you have any of the cameras we have already tested, you can send me a new file and we can see if it actually changes or if it doesn't (my guess: it will fall within 2ms of the number we already have).

[blazer003]

Hey, so I made some clips for you this morning with the GH4. Did it in all pertinent modes and framerates (doh, I forgot to do variable frame rate 96fps, I'll try to upload that later).
http://www.ecf.org/wp-content/upload...s/103_PANA.zip
C4K 24p
UHD 24p, 23.97, 29.97
1080p 24p, 23.93, 29.97, 59.94

*Edit* So I should have read your directions more carfully. Is there a reason to do a 180 degree (1/50 sec) shutter? It seems that sensor readout speed shouldn't be affected by this, and less motion blur, the more accurate, right? I can reshoot again if need be.

Assuming shutter speed isn't an issue, I ran the numbers on a couple frames.
Cinema 4K 4096x2160 @ 24p I came out with .0203 seconds or 20.3 milliseconds.
1080p @ 24p I came out with .0133 seconds or about 13.3 milliseconds.

We'll see how Samuel's numbers come out.