First Blackmagic Cinema Camera Footage Since NAB, Camera Won't Have Optical Low-Pass Filter
Earlier in the week John Brawley, a director of photography helping Blackmagic with the development of their Cinema Camera, posted some full resolution screenshots of footage he’d been shooting with that camera — the first such material since NAB. Now we’ve got the next best thing — he’s posted a minute of footage online. Video samples from this camera have been rather scarce, according to Brawley, since Blackmagic has been working on finalizing the sensor calibration and wanted to wait until they felt good that the calibration and firmware were fully mature. There has been quite an interesting revelation in the past day, however, and it has been revealed that the final camera will not have an optical low-pass filter (or anti-aliasing/blur filter as it is sometimes called). We all know that moire can be a problem on many of the cameras we shoot with (mostly DSLRs), so the big question many are wondering is, how will moire be on the camera now that it won’t feature the OLPF?
The footage has been made available only on the Vimeo page for John Brawley, so you can get there by clicking the video image below:
Here are some of the details about the shoot from Brawley’s blog:
Lenses were the lovely Zeiss Compact Primes…18mm for the wide, 35mm for the panning shot of Casey at the table and most of the closer shots were the 50mm or the 85mm. Exposures were mostly T2.8 or T8 for when I was looking back at the windows. Shooting at ISO800 to ProRes 422 (HQ) in film mode.
The clip was edited in FCPX and then it was exported using XML into Resolve 9, and graded using only single nodes and primaries. The lighting was very minimal, and with such little done to the footage in post, it’s remarkable how nice this camera is rendering colors. The skin tones in the clip have a nice balance without too much red, yet the shirt, her lips, and the red pool balls show excellent saturation and a full range of tones. This type of shot is difficult to replicate with DSLRs without introducing noise somewhere. Often, you can shoot for nicer looking skin tones, but you’ll lose the fullness in the reds, and if you try to bring those back to what they were, there’s a good chance you will be introducing some noise. This is not the case with this footage, thanks to the high bitrate and exceptional color space (ProRes HQ at a maximum of 220mbps and 4:2:2 color). Even the compressed Vimeo footage shows clear separation and excellent tonality.
We have now learned a major detail about the camera, that it won’t feature an optical low-pass filter. I don’t believe this will change, as this is what John Brawley has stated (I’ll be sure to update if this is wrong). It may not suffer from moire and aliasing nearly as badly as Canon’s cameras have in the past. They achieve their image in a very different way, and some of the problems come from the fact that those cameras have to figure out a way to get from 5K down to basically 2K. What this does mean, however, is that very fine detail patterns have a much greater potential of posing an issue. If you’re still reading and have no idea what’s going on, you can read more about the Nyquist and sampling theorem here (have fun with that one if you’re not an engineer, it’s a very in-depth read).
With the way this camera derives its image, I believe the positives will far outweigh the negatives. The huge positive of not having the optical low-pass filter should be improved sharpness. That’s because OLPFs are a trade-off. Make one that’s too strong, and you’ll lose fine detail that wouldn’t have been affected by moire, and make one too weak and you’ll let a lot of moire through. By not having one at all, similar to digital medium format cameras, you should be able to get slightly more overall image quality. This is not too dissimilar to the way the Nikon D800E works, but in that case, Nikon actually used two filters that cancelled each other out. All of these cameras have to have an infrared filter, to block out the infrared wavelength which pollutes much of the color in daylight images.
We’ll see what this will mean for the image soon enough (and how bad moire will actually be), but it may just be another trade-off for maximum image quality and lowest cost.
[via John Brawley]
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