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    Measuring rolling shutter: put a number on this issue!
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    Senior Member Samuel H's Avatar
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    So, in the D5200 thread here, we're kind of worried that this exceptional little toy may have more rolling shutter issues than other cameras.

    This should be a measurable thing: if we knew how many ms it takes each camera to read the sensor, we wouldn't have to be looking at all those piles of not-really-comparable youtube tests.
    Also, when a new camera comes out, we would just have to measure it: no need to compare the D5200 first against a GH2, then against a D800, then a 5D3, then...

    In order to get a half-decent measure of this, I would need to get a very short clip from each camera, shot following these instructions:
    * camera on a tripod, well levelled, set at 24p and 1/50s shutter
    * a vertical line somewhere in the frame, crossing it completely from top to bottom (it can be a pole, or a corner, or a door, etc; if it is clearly tilted it will distort my measure)
    * start recording, do a quick pan left at constant speed, then a quick pan right at constant speed, repeat, reapeat, then stop recording
    (that's a total of 3 pans left and 3 pans right, which will help average off the measurement errors)
    (to get a constant speed, do a long pan that goes on for a while, even if it has to be slower, instead of just a quick whip-and-stop; if you can't find two consecutive frames where the skew looks the same, then the pan is not good)

    If you want to know how your camera fares in relation to others, record that, then send me a link to the unedited file to similaar.feedback@gmail.com (or through a PM on dvxuser) and I'll use two consecutive frames to measure top-to-bottom delay in relation to frame-to-frame delay.

    EDIT, because lots of people write to ask how I measure this:

    First I calculate the horizontal frame-to-frame displacement, e.g. at the top of the frame. Say that's 90 pixels. That means the same portion of the image is moving 90 pixels every 42 ms (actually, 1000/24).
    Then I go to the first of those two frames and measure the horizontal displacement within the frame, from top to bottom of that vertical line. Say that's 60 pixels, which, at 90 pixels every 42ms, means a first rolling-shutter measure of 28 ms.
    Same with the second of those two frames. Say that's 70 pixels; our second RS measurement is 32ms. This means that the camera is accelerating a bit, that's why it's important to measure both frames: there's an error, but it will be averaged out (this is a first-order approximation: if the acceleration itself is accelerating, then that second-order error won't be averaged out, but in most cases that's going to be a very small factor).
    Then look for another pair of frames where the image is moving in the opposite direction, and repeat those three measurements.
    Say our measurements are: 105 for the inter-frame displacement, and 65 and 75 for the intra-frame ones, which gives us measures of 26 and 30 ms. So, the camera was faster this time but we don't really care because we're translating everything into time units; it was accelerating again this time, but as before that's not a (big) problem; and we also know that the vertical line was not perfectly vertical, but that's why we take measures in both directions, again this errors will be averaged out.
    So, the average of those four numbers is 29ms.
    I repeat everything again two or thee times more, because manually measuring blurry images is not an exact science, and that's how I get the final number that I post here.





    RX100 V 250 fps ---- 3.8 ms (3.8-3.8)
    a7R III 1080 S35 --- 6.1 ms (6.6-5.7)
    BM 4.6K (2K crop)--- 6.3 ms (official)
    1DX II 1080p 60&120- 6.7 ms (6.6-6.7)
    XT3 1080p 120fps --- 7.4 ms (7.4-7.5)
    a7R III 1080 FF ---- 7.7 ms (8.7-6.8)
    p4k HD crop -------- 7.8 ms (official)
    NX1 1080p ---------- 7.9 ms (7.7-8.0-8.1-7.8)
    NX500 2.5k --------- 8.6 ms (8.2-8.8-8.9)
    a7 III 1080 FF 25p - 8.7 ms (8.9-8.5)
    a99 II 1080p ------- 8.7 ms (8.8-8.7)
    BM MicroStudio 4K--- 9.9 ms (official)
    a7r II 1080p S35--- 10.5 ms (11.0-10.0)
    a7r II 1080p FF --- 10.8 ms (11.0-10.5)
    1DX II 1080p 24 --- 11.1 ms (11.1-11.2)
    GH5s C4k 24/30 ---- 11.3 ms (Syntheyes)
    GH5s 1080 30 ------ 11.5 ms (Syntheyes)
    GH5s 4k 24/30/60 -- 11.9 ms (Syntheyes)
    a6000 1080p24&30--- 12.2 ms (13.9-11.1-11.5)
    XT3 1080p24 ------- 12.6 ms (12.6-12.7)
    BM 4.6K (4K crop)-- 12.6 ms (official)
    BMMCC ------------- 13.3 ms (official) my measurement was 13.4 ms (13.7-13.5-12.9)
    GH4 1080p --------- 13.7 ms (13.7-13.5-13.1-14.0-13.9-13.5-13.5-13.9)
    RX100 V 1080p ----- 13.9 ms (14.4-14.0---14.2-13.1) (first 2 with stabilization, last 2 without)
    D750 -------------- 14.5 ms (14.6-14.1-14.6-14.8)
    1DX II 4k 24&60 --- 14.7 ms (14.6-14.9-14.9-14.6)
    RX10 -------------- 14.8 ms (14.5-14.8-15.0)
    GH5 --------------- 15.0 ms (official, preproduction)
    BM 4.6K ----------- 15.2 ms (official) my measurement was 16.3 ms (16.3-15.9-16.8)
    a6300 1080p24 ----- 15.2 ms (15.8-14.6)
    Pentax k1 1080p24 - 15.2 ms (15.9-15.7-13.9)
    GX85 1080p -------- 15.4 ms (13.8-16.7-15.7)
    GH3 --------------- 15.5 ms (15.4-15.7-15.4)
    a7R III 4k S35 ---- 16.0 ms (15.6-16.4)
    XT3 4k 60fps ------ 16.0 ms (15.6-16.0-16.3)
    C200 (4k=1080p) --- 16.1 ms (4k: 15.5-16.2-16.9, 1080p: 15.5-16.0-16.6)
    BM p4k 4k --------- 16.2 ms (official)
    a7III 4k 1.2x 30p - 16.7 ms (dpreview)
    G7 1080p ---------- 16.9 ms (17.5-16.3)
    XT2 1080p --------- 16.9 ms (16.9-16.0-17.4-17.3)
    RX100 IV 1080p ---- 16.9 ms (16.5-17.3) (without stabilization it's slightly faster: 16.1)
    RX100 V 4k -------- 17.5 ms (18.1-16.3-17.7---17.7-16.9-18.5) (first 3 with stabilization, last 3 without)
    BMPCC ------------- 17.7 ms (official) my measurement was 17.8 ms (17.7-17.7-20.0-20.0)
    a7s APS-C 1080p --- 19.5 ms (20.3-18.4-19.5-19.5)
    a7R II 4K FF ------ 19.9 ms (19.3-19.6-19.4-21.2)
    5D3 --------------- 20.5 ms (20.7-20.5-20.4)
    XT3 4k 24fps ------ 20.6 ms (20.9-20.4-20.4)
    D5200 ------------- 22.4 ms (22.5-22.1-22.6)
    GH4 4K/UHD -------- 22.0 ms (official) my measurement was 22.5 ms(23.2-22.3-22.7-22.7-22.4-21.8-22.4-22.8-22.6)
    a7R III 4k FF ----- 22.8 ms (22.6-22.9)
    a99 II 4k --------- 23.4 ms (23.3-23.5)
    BMC --------------- 23.6 ms (official) my measurement was 25.0 ms (26.7-24.8-23.5)
    a7 III 4k FF 25p -- 24.3 ms (24.7-24.5.23.7)
    a7 III 4k FF 24p -- 25.0 ms (dpreview)
    5D2 --------------- 25.9 ms (25.5-26.4-25.8)
    5Dsr -------------- 27.7 ms (27.5-27.9-27.6)
    G7 4k ------------- 28.1 ms (27.8-28.5)
    GX85 4k ----------- 28.9 ms (30.2-29.0-28.8-27.5)
    NEX-5N ------------ 29.4 ms (28.8-29.6-28.9-29.8-29.8-29.1-29.7)
    a7s II FF 1080p --- 30.3 ms (29.5-31.2)
    a7s II FF 4K ------ 30.4 ms (30.2-30.6)
    a7s FF 1080p ------ 30.5 ms (30.1-32.0-30.5-30.3-29.2-30.9)
    XT2 4k ------------ 30.7 ms (30.5-30.7-31.2-31.2-30.8-29.9)
    NX1 4K ------------ 30.9 ms (30.6-31.6-31.4-30.7-30.2)
    NX1 UHD ----------- 32.6 ms (32.9-32.0-32.9-32.5)
    a7R II 4K S35 ----- 33.3 ms (35.6-32.2-32.8-35.3-32.6-31.1)
    RX100 IV 4K ------- 36.6 ms (36.4-36.7) (without stabilization it's slightly faster: 35.7)
    a6300 4K 24fps ---- 39.0 ms (39.2-38.9)

    OTHER NUMBERS, MOST OF THEM FOUND BY SQUIG SOMEWHERE ON THE WEB:

    Film --------------- 5 ms? (here)
    Scarlet ----------- 14 ms
    F65 --------------- 14 ms
    AF100 ------------- 14.85 ms
    FS100 ------------- 15 ms
    FS7 --------------- 15 ms (here)
    C300 -------------- 16 ms
    Red One MX -------- 16.6 ms
    7D ---------------- 21 ms
    5D MKII ----------- 25 ms
    GH1 --------------- 25 ms
    D90 --------------- 33 ms

    Last edited by Samuel H; 10-12-2018 at 09:50 AM.


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