Our Phantom Flex 4K cameras have an internal memory of 128GB. When shooting at 4K resolution of 1 : 1.178 (4096 x 2304) the maximum frame rate is 938fps. This equates to 9,709 frames, giving us 10.5 seconds to catch the action in real time. When played back at 25fps this will play out at 6 minuites 47 seconds. Some other companies only offer the 64GB version of the Flex 4K which only lets you capture 5 seconds of real time action. This can obviously be restrictive so always try and book the 128GB version. If shooting with an aspect ratio of 1 : 1.89 (4096 x 2160), 10.356 frames are available, with a maximum frame rate is 1000fps. Shooting at an aspect ratio of 1 : 2.39 (4097 x 1712) 13,066 frames are available giving a maximum frame rate or 1,250fps. The Flex 4K can operate in LOOP mode which means aver 10 seconds of reakl time after starting recording the 128GB RAM goes back to the beginning and starts recording over itself again. The camera is usually set in this mode with a trigger position set to cut the camera once the shot has finished. The camera can run for hours in this mode. For example if waiting for an animal to do something in the wild such as the Great White Shark jumping out of the water in Blue Planet, then once this happens the camera is cut and the 128GB shot is saved to the RAM. This take can then be trimmed to a smaller file size if needed and then saved to a 2TB CineMag within the camera. The camera is then ready to shot again within a minute or two depending on the file size.

Here is a simple guide. When doubling the frame rate, you open the aperture one stop. So for example: 50fps would be + 1 stop compensation; 100fps would be + 2 stops; 200fps would be + 3 stops; 500fps would be + 4.25 stops; 1000fps would be + 5.25 stops and 2000fps would be + 6.25 stops.

So we generally need bigger lights when shooting high speed in order to achieve the 5.25 additional stops for shoot at 1000fps. If using tungsten lights it is safer to use fixtures 5,000W or larger. This is because our AC (alternating current) power supply in the UK runs at 50 Hz. This means the power is delivered in a wave of 50 cycles per second, ie. the current changes 50 times per second. This is fine when shooting up to 100fps, however any faster than that and the camera starts to see the cycle of the tungsten filament cooling and reheating which registers as flicker. Once a fixture of 5000W or more is used, the filament is sufficiently large as to not have time to cool down, hence eliminating the chance of getting flicker. If using fixtures below 5000w or even practical lights on a set, a good trick is to use DC (direct current) power. This can be achieved by using battery power. The current supply is direct and constant and is not in a cycle. The filaments will therefore not be cooling and reheating.

HMI lights are generally flicker free when shooting below 100fps. HMI (discharge lamps) have an arch of light that can be perceived as movement or flicker at higher frame fates. This is the fast movement you can see around the edges of the beam. You see it better if you look away from the light as the receptors around the edges of your eye are more sensitive to movement. It is the same frequency as the output of the ballast, which can be 50 – 100hz depending on the ballast and its settings. Often people call this “flicker” but it is not the same effect as the “flicker” seen on film or a digital sensor, which a “flicker-free” ballast is designed to prevent. Flicker-free blastast run at a frequency of 1000 Hz which eliminates this. Because the supply to the lamp is AC the current flows through the lamp in one direction, stops momentarily as the supply voltage goes through zero and then flows again in the opposite direction. In effect, the arc is collapsing and reforming very quickly each time the current stops. When the arc reforms, it does not always reform in exactly the same place – the “feet” of the arc move on the surface of the electrodes. In fact, this happens at twice the supply frequency, which is beyond the ability of the eye to perceive. However, the eye is sensitive to the changes that occur between one pulse and the next and it is these changes which are at the supply frequency. Once the ballast is tuned to 1000 Hz the cycle goes up to 1000 per second which becomes too fast to register at high frame rates.

LED lights run on circuit boards which use a wide range of frequencies. These practical LED lights that we find in offices, homes and street lighting can suffer from flicker above 100fps. However modern LED lights designed for the film industry are generally flicker free as long as the unit is not dimmed down. As always always test the LED fixture before shooting.

We usually send our PhantomFlex 4K cameras out with with a PL mount to use with 35mm lenses. However on request we can provide LPL, Panavision PV and Canon EF mounts. There is also an option in the camera to de-squeeze the image, therefore allowing the use of anamorphic lenses, both 2 times and 1.3 times de-squeezed.

The Phantom Flex 4K camera can shoot in either RAW or ProRes mode. We always recommend shooting in RAW as this will give you more dynamic range with less chance of blowing out your highlights or crushing you blacks. A RAW file is simply a digital image file that is uncompressed and has has not been processed. It therefore has more information than a processed ProRes file. It is like a digital negative that can be referred back to at any time. All camera manufacturers use their own RAW format. Vision Research use the Cine RAW format. At the end of the shoot, our Phantom technician will dowmload The Cine RAW files from the 10GB CineStation onto your hard drive. You can either get your onset DIT to transcode the Cine RAW files to a file type of your choice or you can hand them over to post production to do this. Alternatively we can provide a DIT for your production.

The camera body weighs in at 14 lbs (6.3kg) and the size is 11.5 x 5. x 7.9 in (LxWxH); 29.2 x 14 x 20cm

The Phantom Flex 4Kcamera has one 24-volt power input, and three standard battery backs are available that support Hawk-Woods, V-Lock and AB-Gold mount batteries. When using 14.4 volts only high-capacity batteries are recommended. The camera is dual powered at all times do guarantee you get the shot. If the camera for any reason loses power than the shot in the RAM will be lost. So if the 24V block battery in accidentally removed or runs out of power then the camera will still be powered by the on-board battery.