Open Source Camera’s CMOSIS sensor getting dialed in
By James DeRuvo (doddleNEWS)
Sebastian of Apertus has released the first dialed in Raw 4K image from the open source, Super35mm Axiom 4K digital cinema camera. And it’s quite a festive one to boot. The 4K image, recorded in CinemaDNG, is part of their ongoing sensor calibration tests, although they admit that the image has no “fixed pattern noise correction” or “hot pixel compensation.” Still, it looks like they’re getting it dialed in pretty good.
This year you can open one present early … First 4K RAW DNG image from our Axiom Alpha prototype … As we’ve previously stated, please keep in mind that our sensor calibration and tuning- alongside our image conversion logic development- have just begun and this image represents a camera in a very early developmental state. – Apertus Website
For a bit of review, the Apertus Axiom is an open source 4K digital cinema camera that is based on a modular design, dubbed the Open Module Concept, which would enable shooters to swap out sensors and other parts as they become more advanced. The Axiom’s features include:
- 4K CMOSIS CMV12000 Super 35mm image sensor
- Global Shutter
- up to 15 stops dynamic range
- high speed at full resolution (up to 150fps)
- Uncompressed Raw
- Full HD at 4:4:4
- Cinema DNG Raw Recording (open source)
- Currently with Nikon F-Mount
The goal is to offer the Axiom at a cost of under $10,000. Which I think he has to do considering Blackmagic’s Production Camera 4K is under $4,000. We’ve seen some really good footage come out of that in a relatively short period of time. But even that footage has made BMD’s Grant Petty come to the realization that the camera should be a general production camera first and foremost. Still, by contrast Blackmagic Design is far down the development road, and is enjoying building upon the success of the original BMCC and the Blackmagic Pocket Cinema Camera. Apertus is starting from scratch, and only recently built their second prototype, which has freed it from it’s breadboard configuration and not into an acrylic camera case for more mobile testing.
Back to the image … Sebastian says that fixed pattern noise is a relatively simple affair to compensate for because it tends to be a static issue that is usually the same with all images. “This is the result of all pixels on the image sensors surface being 100% equal,” Sebastian writes, “and the minor difference in light sensitivity can be noticed in captured images.” He cites that the by reversing some pixel sensitivity, it can correct that noise pattern. “… since its static you only need to conduct this measurement once when calibrating the camera. These measurements are what we are currently doing…”
I dunno. Frankly, I think Sebastian is being too apologetic, because Raw is a huge step. If you click on the image itself, do you really see a lot of this fixed noise pattern? I certainly don’t see it all that much. But it may be that it was compensated for along with the color correction that was done by colorist Aaron Peak at his lab at Hollywood DI. The good news is that the FPN noise compensation is an easy issue to deal with at this stage. Because once you rid the image of the FPN, then it doesn’t matter if you have one still or a 2 hour piece of footage, the noise is dealt with. There doesn’t seem to be a lot of hot pixels either.
Anyway, if you want to take a good look at the Raw image itself, you can download it here.