High Speed and Low Light with the NEX-FS700
Showing off what the FS700 can do, at Cine Gear Expo 2012 in LA.
By Adam Wilt | June 05, 2012
Sony asked Art Adams and me to talk about our experiences with and impressions of the NEX-FS700 camera at Cine Gear Expo in LA this past weekend. Here's my half of our combined presentation.
[First, the usual airline / broadcast disclaimer: "the movie you are about to see has been edited for content, and reformatted to fit your screen." Art's "Betabrand before and after" and FS700 Dynamic Range bits of the preso have been removed, since he wants to discuss them separately. 619-pixel-wide excerpts from resolution charts are shown instead of whole 1920x1080 charts. Embedded YouTube vids substitute for the full-res clips we showed; you can blow 'em up full-screen if you like, but unless your screen is 1920 pixels wide (and you select 1080p resolution), you won't see 'em 1:1, and the "night" clip in particular loses some quality in the YouTube translation, due to the busy-ness of some of the noisier images.]
We opened with clips, then went into discussion...
"Pacific", as shown at NAB 2012.
We said who we were, and what sort of talk folks had stumbled into.
"Fire and Ice" as shown at NAB 2012 (we actually screened an updated version with cleaner titles, though the content is the same).
"Betabrand food fight", as Art discussed last week.
Keep an eye on Art's channel for his discussion.
A quick rundown of what the FS700 is.
What the FS700 offers over the FS100.
The FS700's sensor described.
The sensor is said to have enough photosites for a full, DCI-compliant 4K image—4096x2160—though the camera currently records and outputs 16x9 1920x1080. A future firmware upgrade should, at some point, provide the ability to output "compressed 4K RAW" over the 3G SDI port to an unspecified Sony recorder (not the SR-R1, as it turns out, but some still-to-be-defined device).
However, future specifications may change at any time (shades of RED!), so it's best to treat this as a 1920x1080 HD camcorder until something is actually released.
E-Mount is so shallow it's possible to adapt just about any other interchangeable lens to the FS700 with the right adapter. Sony's LA-EA2 allows phase-detection autofocus (but not image stabilization) with Sony ? lenses. The Conurus / Metabones adapter lets the camera control the iris in Canon EF lenses and supports image stabilization, but not autofocus.
AVCHD recording, plus uncompressed 8-bit 4:2:2 live output.
All internal recording is AVCHD, long-GOP, h.264, 8-bit, 4:2:0 video. Note that Slow & Quick slo-mo and Super Slow Motion must use the internal recording; you could capture the 60i monitoring stream out HD-SDI, but you'd then have to deal with pulldown issues yourself—and 60i will drop frames when recording 120fps and above!
Slow & Quick recording: normal slo-mo.
Super Slow Motion: what sets the FS700 apart.
SSM captures data into a memory buffer at high frame rates, then writes it out to permanent storage.
SSM Speeds & Feeds.
SSM is "full res" at 120 and 240fps, though (as we'll see) with somewhat coarser demosaicing, probably necessitated by the requirement to get data off the sensor with all possible speed. At 480fps, line-skipping is used to keep up (and the reduced data set allows more such frames to be crammed into the memory buffer as a result). At 960fps, the sensor is windowed down about 2x; the reduced frame size (also line-skipped the same way, but at only half the height, it's half the resolution) allows even more storage: nearly 13 minutes' worth!
Though the varying speeds are captured at varying resolutions, they're all expanded back to 1920x1080 for recording, and no speed metadata is stored with the clip: regardless of capture rate, all SSM clips play back as normal, 24fps HD video.
Also, the FS700 is a "WorldCam" capable of working in "PAL" mode as well as "NTSC" mode. In "PAL" mode, S&Q speeds are 1-50fps, and SSM speeds are 100, 200, 400, and 800 fps.
Here are some resolution chards, do you can see what the differing capture rates do in terms of image quality. Any rate from 1-60fps will look just like the 24fps samples; 120 and 240 both have the same image quality as the 240fps sample shown.
Although the charts can look scary, real-world pix normally look better (as we'll see). What's important to note is that at higher speeds, aliasing is worse; while this isn't normally too much of a problem, it can be an issue when shooting the "hero product" in a spot. In the Betabrand footage, for example, you can see a slight moir© on the "disco pants" and "disco skirts" that wouldn't be as pronounced had the spot been shot at 24fps instead of 240fps.
DSC Labs Multiburst Square Wave at 24fps. Any speed from 1-60fps will look like this.
Multiburst Square Wave at 240fps. 120fps would look the same.
Multiburst Square Wave at 480fps.
Multiburst Square Wave at 960fps.
Turn the page: crikey, there's even more!
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