Experiments with cameras for fulldome

To kick things off I thought I would outline some photography and filming options I have been experimenting with. They generally involve a camera (still or video) along with a fisheye lens. This is certainly not intended to be an exhaustive survey, only the combinations I have recently employed.

The easiest is stills, there are a number of fisheye lens options for SLR cameras but many lenses are out of productions leaving one to troll through ebay. Sunex have a 185 degree fisheye for Nikon and Canon APS-C sensors, they are fairly “soft” and it seems the quality also varies on a per lens basis. My favourite lens at the moment is the (newish) Canon 8-15mm fisheye for a full frame sensor. It is unusual for a fisheye to be able to zoom, this lens goes from a full fisheye to about 170 degree diagonal (similar to the GoPro lens). Example from the Moodabidri temple near Manipal, fisheye diameter is about 3600 pixels.

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I use a Canon 5D MKII and in combination with this lens it is ideal for capturing 360 full spherical panoramas, some examples in a virtual environment related to rock art in the Pilbara can be found here: http://paulbourke.net/fun/RockArt/

The Canon 5D (and other) can record HD video but since they use only a portion of the sensor the image is truncated top and bottom, and of course the fisheye result is only around 1K diameter.

Another option is the LadyBug-3 video camera. This was used in the production of “Dark”, see example frame below. The result is about  2.4K fisheye but of course it (like most video cameras) uses a lossy video compression so the effective resolution is somewhat less. One of the nice things about the LadyBug-3 is that it captures 360 degrees horizontally by about 150 degrees vertically, this means the exact angle of the fisheye can be adjusted in post production.

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And finally there is the Red series of cameras, I am currently exploring the Red Scarlet and the Sigma 4.5mm fisheye. The Scarlet has an APS-C sensor as does the Sigma lens but the full sensor size is only available at 5K recording mode which is limited to 12fps. At 30fps the highest resolution is 4Kx2K pixels and since it uses a portion of the sensor there is a slight truncation top and bottom of the fisheye. There are of course ways around this, slightly rotating the fisheye in post or using the camera on the side, or cheating and just cropping to the largest inscribed fisheye. Camera and fisheye shown below.

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A sample frame from the video is given below to illustrate the degree of clipping, please note this is a single frame from a video, not a still shot. The fisheye circle is 2320 pixels in diameter.

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Hope some of this is of interest. Filming for fulldome is certainly still a challenge. In my case much of this is for the iDome so fisheye resolutions around the 2K range are adequate. The next test is with the Coastal Optics fisheye lens, but it priced such that purchasing for testing is a little tricky, doesn’t anyone have one they would consider loaning?

About Paul Bourke

paulbourke.net
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2 Responses to Experiments with cameras for fulldome

  1. Warikl says:

    Great stuff Paul. Fantastic to see that you now have a RED camera to experiment with. Can you tell us more about the production of ‘Dark’?

  2. paulbourke says:

    All in due course, currently concentrating on the final 4K render, finalising credits, final music track … syncing up a launch date at Horizon – The Planetarium.

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