Monday, April 21, 2014

New Camera...thing.

After being completely surrounded by new cameras for a weekend at NAB 2014, I decided to do a little shopping around to possibly update my video camera. My Panasonic HDC-SD60 has served me well, especially with its 20x optical zoom and image stabilization. Pretty much every video on my site for the last few years has been from that camera. (This one is maybe my favorite, and shows its pretty decent low-light performance as well.) But there is so much new video camera technology now that I couldn't resist the urge to do some research into video cameras in the $1-2k price range.

Last year the Blackmagic Pocket Cinema Camera (BMPCC) was annouced at NAB and at the time I thought I might be interested in getting one. It's a really awesome camera because of its size and ability to shoot raw, wide dynamic range HD video, at a reasonable price. My only worry was that is was small enough that I might try to fly it on a smaller-than-adequate multirotor and crash. There's also the Panasonic GH3 (and new 4K GH4 coming soon), which is well-known for its extremely good video quality. It has the same interchangeable lens format (MFT) as the BMPCC.

But I also really like the camcorder format - specifically, a built-in zoom lens and optical stabilization. The BMPCC and GH3/GH4 (and other dSLRs that are out of my price range) have the advantage of large-format sensors that can collect lots of light, something that most camcorders with integrated zoom lenses suck at. But I did find an exception: the Sony HDR-CX900/B (2K) and FDR-AX100/B (4K), both with awesome 1" sensors. Sample footage from the FDR-AX100/B is especially impressive.

So with those as my top choices I considered the pros and cons decided on...

...none of the above.
And here's why: Everything I ever take video of is moving, and moving quickly. Not only that, but the camera usually is moving quickly to keep up. And every single one of those cameras has a rolling shutter, which is something that in my mind I can't understand how the world has come to accept (kind of like Hulu ads that are longer than TV commercial breaks). Looking at the end of this FDR-AX100 test video, it goes from "wow that is the sharpest-looking cat video I have ever seen on the internet" to "okay this is actually broken," in my view. So my solution to the problem was to run away from the consumer market entirely and get a machine vision camera with a global shutter. Specifically, a Point Grey Grasshopper 3 (GS3-U3-23S6C-C):

It's actually a tiny thing!
The body is smaller than a GoPro, but that's a pretty meaningless metric as I will explain shortly. As a machine vision camera, there are no shortage of inexpensive CCTV and scientific lenses for it. And this particular one has a color Sony IMX174 1/1.2" CMOS sensor, which is supposed to be quite good. Most machine vision cameras with global shutter use a CCD, but this new Sony global-shutter CMOS is interesting and hopefully will appear in a Sony camcorder soon, at which point maybe I rejoin the normal world. (Probably not; I am a terrible consumer because I usually think I could build things better from scratch...) But for now, the only way to get this sensor is in an industrial block camera like this.

No that's not a DB9 port...it's a USB3.0 mini-B.
Bill Kerman makes an excellent imaging test subject...
Anyway, the downside of a machine vision camera is that it's missing some (most?) parts a camera normally comprises. You've got a sensor, an FPGA for image processing, and a USB3.0 port. The rest is left as an exercise to the user. In effect, you are tied to a computer for recording the video. It's worth mentioning that the idea of an external recorder is not uncommon in high-end video cameras, so this isn't that unusual. But I did sort-of go in the opposite direction as the highly-integrated camcorder that I wanted. For now, anyway.

The benefits make up for it, I think. For starters, it can shoot up to 162 frames per second at 1920 x 1200 resolution. This is in 8-bit raw mode, so the data rate is 1920 x 1200 x 162 Bytes/s = 373MB/s. (For speed calculation, I'm treating 1MB as 1,000,000 Bytes, not 1,048,576 Bytes.) Color processing of the raw Bayer filter sensor data can be done on either side of the USB3.0 transfer, but for maximum frame rate it is left to the host computer. As for what happens to the data: if it can be written to hard drive space fast enough, it is. If not, as is the case on my laptop, it can be buffered in RAM.

Hrm, time to get an SSD I guess...
The RAM buffer is pretty common in high-speed cameras, but it means your record time is limited. The rate at which raw video chews through RAM is impressive. A fast SSD might just be able to keep up with the USB3.0 data rate, if there are no other bottlenecks in the system. For now, though, I just stuck to short bursts at the not-quite-maximum frame rate of 120fps:


I was playing with different video modes: mostly raw grayscale images and color-processed H.264 compression. (The H.264 encoding seems to be faster than the HDD write speed at the moment.) But yeah, it's certainly capable of high-quality HD video at 4-5x slow motion. At lower resolutions, it can go to even higher frame rates, mostly limited by the USB3.0 data rate.

Did you notice the global shutter? Freeze any of the frames with a propeller in it and the prop is visible in its normal shape...not something ranging from a banana to a boomerang depending on the shutter speed. The shutter can also be set as low as 5μs, meaning you can stop just about anything short of a bullet with enough light. (Ping-pong balls are relatively easy to stop even at ~2ms shutter speed and normal warehouse lighting, as was demonstrated.) 

The shutter can be synchronized with an external digital signal. So I can do this, but without a strobe gun. (Side note: You can see the rolling shutter wreaking havoc on the strobe in that video, and this one too, creating bands of light and dark as part of the image is shuttered with the strobe on and part of it with the strobe off.) The shutter sync works both ways too; it can also output a digital signal that is synchronized to the shutter. I have plans for this feature as well...

One other interesting characteristic of this sensor is that it has quite good low-light performance. This is useful for high-speed video since it can make the most out of the photons it gets with a very fast shutter. But it's also interesting to play with on its own. For example, I can image Bill Kerman in almost pitch black:


It's not nearly as impressive as the Sony A7s low-light demo, but it does produce quite nice video even at night, using the on-board color processor to do some gamma correction. Here's some video taken with just the slightest hint of light left in the sky:


I have no ideas what kind of ISO it can achieve, and it's not a published specification for this camera. (If I had to take a ballpark guess I would say ISO 2000+ with acceptable noise levels? I have almost no feel for that metric, though, so I'll have to try metering it against something.) But it's good compared to any video camera I've owned. Probably not quite as good as a full-frame dSLR. But combined with the global shutter, I think it can do some very interesting night shooting.

So far so good...I have many planned uses for this thing. The next step, though, will be un-tethering it...

Sunday, April 13, 2014

NAB Show 2014

This year was my second trip to the National Association of Broadcasters exhibition (NAB Show) in Vegas as part of the Freefly Systems setup and pit crew. NAB is a huge (~93,000 attendees) expo for media technology, kind of like CES but for the Producers rather than the Consumers. In fact it's in the same venue as CES, the Las Vegas Convention Center.


Last year, the MōVI gimbal debuted and I think I explained the concept of active stabilization (one I can't seem to escape no matter where I end up) to a thousand different people in four days. This year, I didn't even have time to count the number of other handheld active stabilizers there were at the show. Certainly the gimbal trend has taken hold and there is no going back now.

The Birdy Cam!
I think the MōVI brand still holds the top end of the active stabilizer market (highest performance and, yes, highest price). I haven't used and won't ever use this blog for advertising - I'm not good at it anyway - but one big advantage Freefly had was a one-year head start during which some really spectacular footage was created by ever-more-skillful operators, and it's fun to see the results.

One of the event highlights was this interview with Tabb (Freefly president) and Garret Brown, inventor of the Steadicam. I felt like there should be some lighting bolts for dramatic effect given the "Steadicam-killer" hype surrounding handheld gimbals. But in actuality, the point made is an important technical one: active stabilizers control {pitch, roll, yaw}. There are still three degrees of freedom {x, y, z} that are at the mercy of the operator's movement, and Steadicam and its operators have perfected the smoothing of translation over the last 40 years.

Part of the fun of NAB is that I finally get to show off what I've been working on. My big project for this NAB was the EE/software for the new MōVI Controller, possibly the most hardcore-looking RC transmitter in existence:

My pet project, the blue OLED display. (The one on the unit itself, not the SmallHD monitor...) Anti-aliased font support, bitmaps, bar graphs, scrolling, string and numeric formatting, etc., all in a lightweight display driver written from scratch.
The station I somehow ended up manning at NAB: the new controller paired with the largest MōVI, the M15, and the Sony F55, rigged with wireless video and remote focus.
People trying out the new controller. Controlling framing and focus at the same time would take some practice, I think, and there is still the option of having a third operator control focus.
This was a hands-on demo; anyone could walk up and try it out. On one hand this was great, because it means I don't have to hold it the entire time (it was about 18-19lbs, total). But on the other hand, as my Maker Faire experience has informed me, it also means constantly watching the equipment, making sure it stays operational, changing batteries, and reminding people to share...all while trying to answer questions. And of course while most people are very respectful of the hardware, there are the expo trolls who go from booth to booth trying to break things.

In general, booth ops went much more smoothly this year, I think, due to a combination of better preparation and more manpower. There were a few other new toys to keep people engaged as well:

A Zero FX electric motorcycle with a Steadicam arm and M15 gimbal attached to the back. It seems I can't escape electric motorcycles no matter where I end up, either.
The Tero, a 1/5th-scale camera car, made a return as well. It's carrying an inverted M10 gimbal and Blackmagic 4K Production Camera.
Because our hardware was working well, and because we had enough people in the pits to handle the traffic, I actually got to wander around the show floor this year. There was a lot of camera porn, for sure. The Sony a7S was one of the big announcements, a small camera with supposedly epic low-light performance thanks to a full-frame 35mm sensor with just enough huge, gapless pixels for 4K video. On the other end of the size spektrum, AJA and Blackmagic also announced new, relatively inexpensive, 4K professional cameras.

The Blackmagic URSA. I can't get over how nice the machining is. On the other side is a 10" 1080p monitor.
I also went in search of the large active stabilizers - the ones that are mounted to full-size helicopters and camera cars for just about every aerial or car chase scene in a movie ever. There were three that I found at the show this year:

Filmotechnic, camera car specialists, with the Russian Arm and Flight Head active stabilizer (not sure exactly which one).
Shotover K1 full-size helicopter gimbal. This was about twice as large as I thought it was.
Cineflex, about the size I thought it was, but attached to a 27'-wingspan RC plane! Ryan Archer gogogogogo.
Cineflex ATV with one mounted in front and another in back.
A few other random sights of the show:

Crab drive (Or is it Swerve Drive? I can never remember the distinction.) FIRST robot camera dolly.
The circular equivalent of energy chain.
EditShare Lightworks, a powerful and relatively inexpensive video editing tool that I discovered at last year's NAB and have been using since.
Cutaway of a Canon lens...not sure how this even exists.
So yeah, these were just some of the things I saw at the show this year. It's definitely a bit of a circus, with a lot of money spent on impressive booths (and yes, sadly, in this day and age, booth babes are still a thing).

Booth cars I can understand.
Ignoring the flashy bullshit is hard, but underneath there is some cool tech on display and that's mostly what I like to see. Active stabilizers, wireless HD video, less and less expensive high-quality video cameras, more accessible software, etc., all make for an exciting media era - one for which I will happily hide on the engineering side.