by Graham Sheldon | 26th October 2016
The Chronos 1.4 camera is the result of the efforts of a single engineer, David Kronstein, who is working diligently to bring slow motion to a wider group of filmmakers. The device – now “production ready” and headed to Kickstarter in the “next few months” for funding – is capable of 1050fps at a resolution of 1280×1024. Read on for all the details, including footage samples: Shooting great-looking slow motion is really, really expensive and usually requires renting a Phantom high-speed camera for the best shots at 300 fps+, or an equally pricey RED Epic Dragon or Weapon for anything below 300 fps. Slow motion, however, is almost always worth it. Don’t take my word for it – just look at the trailer for Planet Earth II here, which includes some epic slow motion moments. The YouTubers over at the “TAOFLEDERMAUS” channel have gotten their hands on a prototype production model of the Chronos 1.4 and have in-camera footage to show as well: As you can see from the video, there are still a few kinks to work out: there is a 30 second boot up time from the moment the power button is pressed, and saving to SD card takes a considerable amount of time as well, but hopefully we’ll see improvements as the project progresses. This is very much a speciality tool, especially given the lack of full 1080p resolution, but it is cheap and shows promise at being a no-fuss slow motion solution in the future. Once fully funded through Kickstarter, the 8GB base model of the Chronos 1.4 is expected to cost a (comparatively speaking) very affordable $2,500. Chronos 1.4 Tech Highlights: 1280×1024 at 1050fps 21,650fps at its lowest resolution of 640×96 Aluminium Frame C-Mount Lens Compatible Weight: 3.3lbs Media Type: SD Cards, or save footage to USB or eSATA drive File Type: MPEG-4 Shoots RAW Touchscreen Pre-Record Mode Available with 8GB or 16GB of RAM Power: AC Adapter, Nikon EN-EL4A Battery, or internal chargeable battery. The below video was created by the engineer behind the design, who shows off some in-camera video while going into more detail on external ports, internal mechanics, as well as a ring near the sensor that adjusts back focus. Skip ahead to 9:27 for in-camera footage: The Chronos 1.4 project is ambitious, and though I’m hopeful this camera will one day be available for the mass market, we shouldn’t lose sight of the fact that crowd funding has a dubious history and caution is recommended with products like this. Still, we’ll keep an eye on the project and update as more information comes our way.Read more
by Nino Leitner | 10th August 2015
Convergent Design announced a firmware update for their Odyssey7Q and 7Q+ recorders which enable continuous high speed ProRes recording in 4K, UHD and HD, at 60p (in 4K/UHD) and 240p (for HD). The free firmware update can be downloaded from their site but requires the optional Odyssey RAW bundle to work. Right now, the Sony FS700 and FS7 (only with the XDCA Extension Unit) are supported, but additional cameras will be added in the future. The update also includes RAW support for the new Canon C300 Mark II, enabling 4K and QHD RAW recording from the camera, at up to 30p. In this video, Convergent Design shows how to set up high speed ProRes recording: Here’s the full feature list of Odyssey firmware v2015.8: NEW FEATURES (Odyssey7Q+) Canon XC10 Support UHD Apple ProRes 23.98p, 25p, 29.97p UHD->HD SuperSample to Apple ProRes 23.98p, 25p, 29.97p (Camera trigger & HDMI timecode in HD Only) NEW FEATURES (Odyssey7Q+, Odyssey7Q) FS7/FS700 High Speed RAW -> Apple ProRes Support* [MORE INFO] FS7/FS700: 4K RAW -> 4K Apple ProRes, 50p & 60p added 4K RAW -> UHD Apple ProRes, 50p & 60p added 2K RAW HS -> HD Apple ProRes, 100p, 120p, 200p, 240p (Only one SSD can be mounted for recording 2K HS Apple ProRes) (Only Odyssey int. TC supported (Seed, Time-of-Day DF & NDF) FS700 only: 4K RAW Burst -> 4K Apple ProRes, 100p & 120p 4K RAW Burst -> UHD Apple ProRes, 100p & 120p (*Requires Odyssey RAW Bundle or Sony FS RAW Option) Canon C300 MKII RAW Support 4K RAW recording up to 30p QHD RAW recording up to 30p 4K RAW -> 4K Apple ProRes up to 30p QHD RAW -> UHD Apple ProRes up to 30p (*Requires Odyssey RAW Bundle or Canon RAW Option) NEW FEATURES (Odyssey7Q+, Odyssey7Q, Odyssey7) Vectorscope Analog or Digital Trace Trace display in green or color (true CbCr) Variable Zoom 1.0x – 15.0x (Finger Drag left-right) Zoom Presets 1,2,5,10,15x (Finger Drag up-down) FIXES & IMPROVEMENTS FIXED Audio issues in 1080i59.94 playback FIXED 4K to 2K/HD Downscale Line at the bottom of image. IMPROVED Color Bars IMPROVED Odyssey Menu FontRead more
by Richard Lackey | 30th April 2015
Let’s face it, slow motion is bad ass. You don’t get more bad ass than this amazing shot of a .500 S&W Magnum by Herra Kuulapaa (www.kuulapaa.com). While this may be an extreme example, and it’s a still, not a grab from motion, nothing gets the imagination going quite like the ability to shoot high frame rates. Give yourself the edge by understanding the fundamentals of global vs rolling shutter, shutter angles and exposures at high frame rates. A few weeks back I wrote an article “8 Essential Steps to Perfect Exposure – The Knowledge Any Cameraman Should Have”. If you haven’t read it yet, now would be a good time to do that, and then come back to read this one. 1. Mechanical Shutter In a film camera, the shutter is a mechanical rotating mirror. As it rotates 360 degrees per exposure it alternates covering and uncovering the film gate for a particular amount of time. The RPM of the shutter is mechanically fixed and determined by the frame rate, and the exposure time is determined by the shutter angle. During exposure the film is held perfectly still, often with registration pins. While the mirror shutter covers the film gate, the pins mechanically disengage and the pull down claw physically advances the film to the next unexposed frame. 2. Rolling Shutter Many electronic shutters in digital cinema cameras feature a rolling shutter, where data is read out line by line from the top of the sensor to the bottom before being reset ready for the next frame exposure. A rolling shutter can exhibit a noticeable skew of would-be vertical lines in the image if either the camera or subject is moving quickly across the frame. This can create unwanted motion artifacts warping the whole image if the sensor read-out is particularly slow and there is fast motion in the frame. Most rolling shutters are incredibly fast, minimizing potential problems. Red and Arri among many others employ rolling shutters, and the results can lend a more “cinematic” feel than a global shutter. Even extremely high frame rate cameras such as the Phantom digital cinema cameras from Vision Research employ rolling shutter, but with a readout-time of only 1 millisecond. In this chart you can compare rolling shutter readout-times of different camera models we tested in our lab: 3. Global Shutter A global shutter differs from a rolling shutter in that at the end of a full exposure, light is blocked entirely across the sensor all at once while data is then read and it is reset for the next exposure. A global shutter preserves the perfect vertical alignment of vertical lines or objects moving horizontally through the frame. However, the feel of motion can be noticeably different. Depending on how a global shutter is implemented, there can be a small cost in light (fill factor) and possibly dynamic range when compared to a rolling shutter. 4. Shutter Angle Shutter angle is a term that refers to the actual physical angle of the opening in a rotating mechanical shutter in degrees. The angle of the opening determines the duration of the exposure as the shutter rotates. Mechanical shutters for the most part are gone in digital cinema cameras, but often the terminology has stuck. Shutter angle is your control of motion blur. The longer the exposure, the more motion blur, the shorter the exposure, the sharper any moving objects will appear. It can be calculated easily to a fraction of a second exposure time. Exposure time (1/x sec) = Frame Rate x (360 / Shutter Angle) For example, at a frame rate of 24fps at 180 degree shutter (180 degrees is considered normal): 180 degrees: 24 x (360 / 180) = 1/48th second Here is a whole table calculated for 24fps for shutter angles up to 220 degrees: 15 degrees = 1/576 sec 20 degrees = 1/432 sec 40 degrees = 1/216 sec 60 degrees = 1/144 sec 80 degrees = 1/108 sec 100 degrees = 1/86 sec 120 degrees = 1/72 sec 140 degrees = 1/62 sec 160 degrees = 1/54 sec 180 degrees = 1/48 sec 200 degrees = 1/43 sec 220 degrees = 1/39 sec Any change in shutter angle changes the exposure time, and will need to be compensated for with a change in aperture to maintain correct exposure. Of course a change in aperture will affect depth of field. So if depth of field needs to remain unaffected also, the only thing left is to add ND filters (if reducing light to compensate for a longer exposure time) or increase the actual light levels illuminating the scene (if compensating for a shorter exposure time). If we consider 180 degrees as the base (normal) angle as “Full Exposure”, the following compensation table applies. Shutter Angle F-Stop/T-Stop Compensation 197-200 Close 1/4 166-196 Full Exposure 148-165 Open 1/4 135-147 Open 1/3 121-134 Open 1/2 111-120 Open 2/3 99-110 Open 3/4 83-98 Open 1 74-82 Open 1 1/4 68-73 Open 1 1/3 61-67 Open 1 1/2 56-60 Open 1 2/3 50-55 Open 1 3/4 42-49 Open 2 37-41 Open 2 1/4 34-36 Open 2 1/3 31-33 Open 2 1/2 28-30 Open 2 2/3 25-27 Open 2 3/4 22.5-24 Open 3 5. High Frame Rates In the age of digital cinema, more than ever before there is a demand for high frame rates in our cameras. This used to be a specialty requirement but is now expected. Capturing the spray of ocean waves in crisp frozen detail, liquids pouring or simply the beauty of smooth slow motion is no longer out of our reach. Many cinema cameras can now shoot at least 60fps if not much higher. Vision Research has been on top of extreme high speed cinematography for some time. While 1000 – 2000fps is still out of reach for most of us, cameras like the Phantom Flex 4K are pushing the limits of what can be achieved. Be aware of how high frame rates impact your exposure (and light requirements). For any camera, regardless of sensor, regardless of manufacturer the same rules are true when it comes to high frame rates and exposure. It’s purely mathematics. Every time you double the frame rate, you are halving the exposure time for each frame… and halving the amount of light hitting the sensor. For an example, lets assume a “normal” shutter angle of 180 degrees. At 24 frames per second, with a 180 degree shutter gives us an exposure time of 1/48th sec. If we double the frame rate to 48fps, with the same shutter angle we halve the exposure time to 1/96th sec. We’ve just lost a full stop of light and are only at 48fps. Let’s extrapolate this out and I’ll rather use 25fps as a starting point instead of 24fps because it will multiply out with round numbers: 25fps @ 180deg = 1/50th sec 50fps @ 180deg = 1/100th sec (1 stop loss) 100fps @ 180deg = 1/200th sec (2 stop loss) 200fps @ 180deg = 1/400th sec (3 stop loss) 400fps @ 180deg = 1/800th sec (4 stop loss) Of course frame rates can be anywhere in between these numbers but I’ve simply doubled it every time for the example. So you can see we’re losing a stop of light every time we double the frame rate. Losing a full stop is not a small amount of light. Every stop lost is a halving of light. 1 stop loss = 1/2 the light 2 stop loss = 1/4 the light 3 stop loss = 1/8 the light 4 stop loss = 1/16 the light Just as a change in shutter angle at a normal frame rate affects exposure time and requires a compensation to be made in lens aperture or lighting, high frame rates require even more compensation beyond just opening up the lens. This means if you have enough light for a correct exposure at 25fps and you don’t want to affect your depth of field (by opening up your aperture), you’ll have to double the amount of light used to light your scene or subject to get the same correct exposure at 50fps. You’ll have to quadruple the amount of light on your subject to have a correct exposure at 100fps. This just doubles every time, so to have a correctly exposed image at 200fps you need 8x the amount of light on your scene as you would at a normal 25fps frame rate. The sun gives us plenty of light for this, so outside under daylight, compensating for the much shorter exposure times when shooting high frame rates is much less of an issue. However, inside under artificial lighting… you have to crank up the light seriously (double it) every time you double the frame rate. It’s normal that high speed table top shoots for instance require a ton of light. If you are on set when shooting a product shot involving a liquid pouring and they have a Phantom on set shooting at 1000fps, they will have serious light on that product. 6. Base Sensitivity When it comes to high frame rates, a higher “native” base ISO or exposure index (EI) is always beneficial. Keep this in mind when comparing cameras. Every sensor is different and every camera will perform differently capturing high frame rates. If a particular camera gives brighter images at high frame rates, it’s either because the sensor has a higher base ISO or it can be pushed above its base ISO with acceptable noise. Base sensitivity of a sensor is down to many things, simplest of which is the size of the photosites (but that is a huge simplification), and this is determined by how many of them are crammed onto the sensor. If you increase resolution (or number of photosites) and keep sensor size the same, the photosites get smaller and as a generalization, base sensitivity will decrease. The amount of space between photosites is also a factor, and the amount of space needed for circuitry at each photosite. 7. Shot Noise In the end regardless of all this there is “shot noise”, a minimum level of “noise” when counting or detecting small numbers of photons that is due to variations in quantum probability. If you throw one single photon at a surface with 50% reflectance, there is a 50% probability that it will be reflected or absorbed. So that surface could show up if the photon is reflected and detected at a photosite, or it could be black if the photon is absorbed rather than reflected. The more photons that are thrown at the surface, eventually probability dictates that 50% will be reflected and 50% will be absorbed. If you flip a single coin, it will land either heads, or tails but there can only be one possible outcome and the probability is equal it could land either way. If you flip 1000 coins, you should on average count 50% heads and 50% tails. I don’t want to over-play “shot noise”, it’s only a factor at extremely low light levels, but I just want to point out that even if an image sensor is otherwise perfect (which none are), it does define a impenetrable minimum noise floor that is simply down to quantum physics. Other types of noise also come into play such as Fixed Pattern Noise (FPN) which is caused by non-uniformities of the sensor in the manufacturing process. FPN is fixed and can be mapped out, however other types of temporal noise are more difficult to reduce. 8. Light A image sensor will always perform best when there is plenty of light, and when you have very short exposure times for each frame (as in pushing higher frame rates) the only solution is more light. As I have explained before in “8 Essential Steps to Perfect Exposure – The Knowledge Any Cameraman Should Have” exposing your sensor properly is the single most important key to achieving the image you envision seeing beautifully graded and finished after post production.Read more
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