Test camera AJA RovoCam 4K

This week we tested the new RovoCam from AJA to see if we could improve the recording of our hands in studio.

The problem: If we choose a better camera with a nice big sensor it will create moiré with the Wacom® Tablet 24 inches that we use. This is because the distance between the camera sensor and the tablet is just the perfect one to create interferences with each respective “pixels” grids (the sensor and the screen).

The solution: Use of a smaller sensor for the camera. Changing the distance of the camera and the tablet will not help because we would need to zoom the image to fill the screen with the tablet and it would result in the same ratio (pixels screen-sensor) and recreate the moiré.

Pros:

  • Nice image quality
  • No Moiré
  • HDBaseT camera! (accept 100m of cat6 cable distance)
  • 1080p50 and 1080p60

Cons:

  • No Zebra controls
  • Focus not constant when changing the zoom.
  • The minimal distance focus is changing drastically while zooming.
  • No way to easily set the focus manually. Normally you would zoom in, set the focus and then zoom out but because of the focus not constant and the focus distance restricted by the zoom, this is not feasible.
  • A manual focus helper in software would be great
  • Strange behaviour selecting the 1080i25 is accepted by the recorder (BlackMagic® DeckLink 2) as a 1080i50?
  • No 1080p25 or 1080p24
  • No 1080i50 selection (but see workaround)
  • RS232 to USB controls not working with ElCapitan, no way to use the RovoControl software with ElCapitan so no ability to setup the camera… unless you connect it to an older Mac OS (it was working on OS X 10.9)
  • RovoControl 1.0 seems to have trouble with changing parameters between Auto and Manual. I could not set the Shutter speed manually every times I selected a speed like 1/60 it jumped to 1/2000 by itself. Also, when I tried to set the focus to manual then switching through the tabs of the apps from Camera Control to Settings and come back to the Camera Control. The focus was reset to Auto. (*)

(*)Tips: by setting a preset, it seemed that the parameters was responding correctly.

 

Tests:

I checked an option allowing the camera to film in 4K and crop a point of interest of 1080p in the sensor called ePTZ. The option is nice but the image quality is impacted. I believe this is due to the fact that the sensor used in normal HD (1080p) will use the full surface of the 4K sensor (4K -> 1080p) and do an interpolation of the pixels that allow a clean image. When you use the ePTZ option you will have only the 1080p part in the 4K sensor and it will give a bigger signal/noise ratio deprecating the image quality.

The Settings for the hands recording:

the red cable is a 50m long network cable connected to the receiver here. I also needed to convert the HDMI to SDI because the BlackMagic card accept only SDI inputs.

IMG_4186

Images result of the hands:

The settings for the focus and color measurements:

I mounted the grids and measurement from our Spider box on a hotshoe slider then fixed it on a light stand. Like this I could film the colours pattern and the focus ruler in same time in front of the camera.

Cropped images for focus testing:

RovoCam_focus

Here we can see a 200% zoom that will reveal the compression destruction between ProRes LT and ProRes proxy. Also we have less difference when recording in 50p vs 50i.

RovoCam_focus_zoom

 

 

 

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