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05-10-2013, 04:26 AM   #1
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Dynamic Range?

Has anyone done any tests on the K-01's Dynamic Range, or know of any tests that are online?

I'm looking for test cards that I can display on an LCD, so I can record footage of the screen and then open that footage in Edius and display on the waveform monitor.
The one decent image I have so far has 10 steps between black and white, and my K-01 handled that with ease, the stair-step in the waveform monitor had all ten steps plus black, with no clipping of the white.

I know that's not a proper test,.. I'm Googling for test charts and how to light them at the moment.

05-10-2013, 04:28 AM   #2
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DxOMark - Compare cameras side by side

12.9
05-10-2013, 04:57 AM   #3
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12.9 stops?

Waiting for that site to load,.. 'net is slow at home

Shall be interesting to see the results,
05-10-2013, 05:53 AM   #4
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Yep EV stops

05-10-2013, 10:58 AM   #5
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Not entirely sure if the number of Stops when taking a photo translates directly to Video.
My rough estimation from the cards I've been able find and display, the recorded vision is showing what I think is 10 or 11 stops.
That puts the K-01's dynamic range ahead of the 5D's, and just behind the BlackMagic Design cameras.
05-10-2013, 11:18 AM   #6
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What prompted this, is the challenge of what I was involved in shooting on Thursday night, see the image for the difficulty rating - I set the exposure/ISO so the hands and white keys would be correctly exposed in the close-up, which is what this angle will be mostly used for.

The deep glossy finish of the Piano made judging overall exposure difficult - this was 1/50th (because 25p), t3.5, ISO 400 - and the numbers flashing red at the bottom of the screen. Tilt up and pan left, getting the wood work at the back of the stage in more then 70% of the frame, and the red flashing turned solid white, even though the Piano was where the stage lights were pointed.

That much black toned material in the frame must have been playing havoc with the CoDec, ditto with the reflections in the surfaces.

Watching the footage back on a HDMI connected monitor makes me rather happy.

(Images captured to Jpegs in VLC, compressed and resized to 1000 pixels wide for upload.)
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05-11-2013, 03:29 PM   #7
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QuoteOriginally posted by PiDicus Rex Quote
Not entirely sure if the number of Stops when taking a photo translates directly to Video.
My rough estimation from the cards I've been able find and display, the recorded vision is showing what I think is 10 or 11 stops.
That puts the K-01's dynamic range ahead of the 5D's, and just behind the BlackMagic Design cameras.
Video has a lower dynamic range, not sure how much though but the h.264 is quite limiting.
I wonder if the K5 fair better.
05-12-2013, 12:58 PM   #8
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That second shot is impressive! What custom image setting are you using? What do you find best (for color grading in post)?

05-15-2013, 12:02 AM   #9
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Thanks John, it was pretty difficult to get right. A quick and rough grading of the footage, with most of the work centered on the Y curve, brought out quite a fair bit more detail, especially in the reflections, and along the side of the piano body.

Anvh: Yep, video is limited in dynamic range, the REC 709 specifications limit the number of steps between black and white. Using a picture preset like "Muted" instead of "Natural" or any of the heavily saturated presets, helps to bring more of that picture information to within the 709 bandwidth.

Without the ability to record "raw" video, the top and bottom ends of the exposure data is effectively thrown away by the camera before the video gets compressed. The amount of compression should not limit the dynamic range any further, but it will limit the rate of change the CoDec can express between adjacent pixels.

In the raw ( or in uncompressed vision from the HDMI port,... ) vision, a black pixel and a white pixel sitting next to each other will be expressed with no alteration. But as the data rate drops ( as the amount of compression applied is increased ) the bandwidth available to display data drops, the rate of change between pixels becomes limited, and so grey pixels may be drawn between the black and white pixels.
Compress the data far enough, everything becomes greyed out.
To the eye, this is when the video begins to look 'soft'.
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