Sony NEX-FS700 in the Raw

On to res charts: This first set is from last year’s preso and you’ll find 1:1 extracts in that article. If you prefer, just click these pix for 1920×1080 originals. Though they’re a bit over-compressed for the web (sorry ’bout that) the important resolution info comes through; just don’t look at these images as being representative of the source material’s compression quality.

All the following were shot using on-board AVCHD recording:

At 24p (and at 1-60 fps Slow & Quick) the camera is a clean, 1080-line camera with minimal aliasing.

At 120 and 240 fps, there’s some sort of resampling going on: the camera still gets out to 1080 lines but with a higher degree of aliasing. For the most part it’s not objectionable in real-life image.

At 480 fps we drop down to about 432 lines vertically, with vertical aliasing increased (of course).

At 960, we’re severely undersampled in both H & V, and overaliased: it’s more a special effects more than a normal-picture mode, but it can be useful on occasion.

Next, the same speeds on a DSC Labs Mega-trumpet chart. Again, see last year’s writeup for 1:1 details, or click these pix for 1920×1080 versions:

I screened a sample clip of the various slo-mo speeds; it’s the same footage shown in this article, from 0:20 to 1:06 or thereabouts.

Now, onto raw recording. The 2K charts show exactly the same artifacts as the 240fps AVCHD charts above; I surmised (and Sony confirmed) that the same pixel-binning used for 240fps is used in all 2k raw capture: that’s how the Sony gets 2K out of a 4K sensor yet maintains the same sensor active area.

Now, if we look at 4K, 1:1 (that is, a 1920×1080 extract from the 2160-line-tall chart shot)…

…we see that the FS700 is clean right up to 2000 lines. So we can’t see anything this way. Instead, let’s zoom out 2:1…

…and now we can crop in 2:1 on the charts and see ’em showing, in effect, twice the resolution (click to enlarge):

The camera goes right up to 2160 TVl/ph, with some aliasing beyond. 2160 lines is the absolute theoretical limit for this sensor, so Sony has clearly optimized the optical low pass filter and the deBayering for sharpness—with, as an unavoidable side affect, a bit more high-frequency aliasing.

In practice, the camera is almost painfully sharp; much crisper than a RED at the same resolution (in RED’s defense, they’re very conservative in their OLPF and deBayering, to get as much detail as possible without generating noticeable aliasing). Whether you prefer the FS700 or a RED in this respect is a matter of personal taste; practically speaking, it meant I could push in nearly 2:1 when extracting HD from a 4K shot with no noticeable softening.

Even better: there’s no degradation in Super Slo-Mo: the chart looks just the same.

Here’s a 4K slo-mo clip (and yes, it’s uploaded to YouTube at 4K, so if you have a 4K display or anything beyond HD resolution, select “original” quality): FS700 4K Slo-Mo

 

Next: Super Slo-Mo; shooting and posting a simulated car commercial; observations and final thoughts…

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About The Author

Adam Wilt is a software developer, engineering consultant, and freelance film & video tech. He’s had small jobs on big productions (PA, “Star Trek: The Motion Picture”, Dir. Robert Wise), big jobs on small productions (DP, “Maelstrom”, Dir. Rob Nilsson), and has worked camera, sound, vfx, and editing gigs on shorts, PSAs, docs, music vids, and indie features. He started his website on the DV format, adamwilt.com/DV.html, about the same time Chris Hurd created the XL1 Watchdog, and participated in DVInfo.net‘s 2006 “Texas Shootout.” He has written for DV Magazine and ProVideoCoalition.com, taught courses at DV Expo, and given presentations at NAB, IBC, and Cine Gear Expo. When he’s not doing contract engineering or working on apps like Cine Meter II, he’s probably exploring new cameras, just because cameras are fun.

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