What is 4K and why is 4K Red four times the resolution of 2K HD (Sony/Panasonic HD formats)?

4K refers to the camera's resolution. The 'K' refers to one thousand pixels.

2K HD (1920x1080) has nearly 2000 pixels across the image sensor (in 1080 horizontal lines giving a total of 2.07 million pixels).

4K RED (4096x2304) has just over 4000 pixels across the image sensor (in 2304 horizontal lines giving a total of 9.43 million pixels).

Therefore, Red 4K is four times the resolution of 2K HD because there are four times the number of pixels, despite the headline resolution sounding like only twice the number of lines!

On the Red One, the full size of the sensor is actually 4700 x 2450 pixels = 11.94 million pixels, but the camera uses the excess as a 'look around' to help with composition.

What slow-motion capabilities does the Red One have?

The Red One shoots at 2K resolution at up to 120fps (compared with Panasonic's Varicam that shoots up to 60fps), 3K at up to 60fps or 4K at up to 30fps, all with progressive scan.

What are the advantages of Red 4K?

When shooting slow-motion, instantaneous playback is possible in camera, so effects shots can be replayed and reviewed straight away.

Even if your final product is to be delivered on standard definition video, there are still good reasons for shooting Red 4K. Unlike Sony and Panasonic's HD cameras, the 4K image doesn't get sharpened electronically, meaning the pictures are more natural looking and less video-like. The more detail you capture, the more superior the finished image is and you will get a crisper, richer picture when the image is resized downwards. 35mm film looks better than 16mm film, even when they are both displayed on a standard definition screen. Both were traditionally used in high-end drama and films with this advantage borne in mind.

Even if you're delivering 2K HD, the format has the advantage that you can re-frame, electronically stabilize the images or zoom and track in post- production with no loss of quality at all.

Traditionally, when shooting video, the camera setup requires predetermined adjustment of colour temperature, exposure, gain, sharpening, electronic knee, toe and pedestal levels before recording the signal. The Red One records the data as a R3D RAW file, which is basically the video equivalent of RAW files in stills photography. This allows for significant changes to be made in the "look" and grading of the pictures in post-production.

Previously only possible shooting on 35mm film, large screen features can now also be shot digitally and transferred to film for viewing on the big screen, or ideally shown digitally with 4K digital projectors onto cinema screens.

What is significant about 'the look' of the images that the Red One produces?

The Red One's large sensor means that using standard PL mount S35mm film lenses, the images differ from that produced by any smaller 2/3" HD format. They will look richer, with a reduced depth of field giving what is frequently referred to as the 'filmic look' so often requested by directors.

The Red One has a progressive scan sensor, and doesn't shoot interlaced images (traditionally associated with video cameras - SD and some HD). This method of scanning each frame emulates the motion of a film magazine running through a film camera and this artifact adds to the 'filmic' qualities of the images.

What lenses can I use?

There are a number of different mounts available for the Red One, but the most commonly used is the PL mount, allowing the use of any 35mm lens. The top end manufacturers include Arri, Angenieux and Cooke. There are other lenses available from Nikkon, Canon and from Red Digital Cinema too, but these mostly find their way into the owner/operator market where investment in lenses and lens sets costing tens of thousands of pounds is unusual. As the format can be considered a direct replacement to 35mm film, it would seem unwise to skimp on the most important factor in getting the best images possible to the sensor to be recorded.

The different brands will all have their own associated 'look' based on colour rendition and crispness with some DOPs having a specific preference or requirement. Commonly, the professional lens sets and the Angenieux zooms will all have matching T-stops, making lighting simpler and quicker, without the need for exposure compensation or lighting adjustments.

How do the different Red One resolution settings affect the field of view of the lenses?

When altering the resolution, the camera uses a smaller portion of the sensor (called windowing or cropping). The field of view of the lenses is therefore altered when compared to shooting at 4K. So if the Red One's resolution is switched from 4K down to 2K, then the focal length of the 35mm lenses will be doubled. Therefore, a 35mm lens will become a 70mm, and a 50mm lens will become a 100mm lens etc. This can be helpful if you need telephoto shots that may be tighter than you would normally be able to achieve with the focal length of the lenses that you have. It might also be useful to take this into account when trying to match shot sizes between resolutions by sticking to shooting on focal lengths that you know you can match doubled in your lens set!

What ISO is the Red One camera rated at?

The ASA/ISO of the camera can be considered as being in the 320 - 500 ASA (measurements of film sensitivity) range. As the Red One records a RAW signal directly from the Bayer-filtered sensor, giving it different ISO/ASA ratings in the menu really means processing the signal in order to boost the gain, like a video camera does. The 320 ASA rating will give the images a low noise floor, but you could rate the camera at 500 or 1000 ASA if you choose to, record the signal and then in post, brighten it to look normal, but at the cost of increased noise. ASA ratings for digital cameras are somewhat flexible -- it all depends on the noise level you can live with or find acceptable. Once you test the camera to learn its effective exposure range, you could certainly just use a light meter like with film and just keep an eye on the extreme ends of the exposure range. A waveform is more useful in telling you if large amounts of information are close to being crushed or clipped so you can decide whether to expose a little more up or down to hold more information. Generally, you will tend to base your exposure on the subject itself, often a human face, and how you want it to look in terms of luminence. Relative to other digital cameras the Red One has a very low signal to noise ratio (66 decibels). In practice this means the camera can be easily 'pushed'¬ù to rate at around 1000 ASA with very little noise visible in the shadows. You should have no problems shooting in significant candlelight, for example.

What is the role of the DIT?

With large amounts of data to be handled on a shoot, a new role of DIT (Digital Imaging Technician) or Data Wrangler has been created.

Initially, the DIT will organize and implement all camera settings to correspond with DP's specified instructions. This includes project settings, sensor settings, metadata, colour and 'look' files, audio menus, time-code sync, frame guides etc... He will then develop the appropriate monitoring configurations and conditions for all necessary crew members (i.e. DP, Director, Client, Focus Puller, Sound Recordist etc...) to have access to the necessary information.

The DIT is on hand to assist the camera crew with all camera settings and relevant changes to the Red One configuration as and when they become necessary.

The DIT will then organize and operate a DIT station to manage and back up all data (rushes) from shoot. This station is equivalent to a 'loading station' for a film shoot. The station will require power supply to Laptops, RAID arrays, battery chargers, monitors etc. However it is possible to run a low key, battery powered station for 'in the field' shooting for short periods of time.

Data management is the core of the DITs role. Each new digital magazine to be used on the Red One must be correctly formatted and prepared for use on the camera, with complete metadata information for use in postproduction. The time taken to change a digital magazine is equivalent to that of changing a film magazine and similar strict etiquette and systems must be adhered to as the data will be permanently erased from the Red Drive before re-use. The captured footage that is removed from the camera is backed up immediately onto separate hard drives, into a pre-organized file structure that details shoot, date, roll and mag ID info for easy later access, both on set and in post-production.

The DIT will have Red-Cine loaded onto his computer. This software allows the DIT to display the recorded RAW images to the DOP or Director. The software allows for sophisticated display and control over the Images, so it is possible to simulate a 'look' or 'first light grade' adjusting exposure, colour balance and gamma curves to display the potential for grading and manipulation in post-production. This process is separate and non- destructive to the recorded data.

If required, the DIT can load offline proxy versions of the footage into Final Cut Pro to demonstrate how shots might look together as part of a cut or sequence.

How is the Red One footage recorded?

The images are stored as R3D files. Uncompressed, with current storage limits of digital media, the 4K images would be too big to be practically useful as video, so Red developed Redcode to compress the data to manageable file sizes. To date, there are two formats: Redcode 28 and Redcode 36, with the latter being less compressed. Red are calling it 'visually lossless'. They claim tests have shown it is impossible to distinguish between compressed and uncompressed footage.Less compression means more storage space, but better images, more suitable for special effects and high-end work.

The Red One records to either Compact Flash or Red Hard Drives.

Compact Flash is robust and able to deal with harsh, high-vibration shooting conditions like helicopters and car-mounts because there are no moving parts. 16Gb CF cards will allow for about 8 minutes of recording at 4K.

320Gb raided hard drives will store around 180 minutes of Red footage, although in practice these drives are rarely filled. It is unwise to load a hard drive to its capacity and the reality of shooting means that often the quickest and most secure workflow on set is to regularly download the R3D files from the Red Drives. This keeps your DIT (Digital Imaging Technician - or Data Wrangler in the U.S) working efficiently and means they are not left at the end of the day with masses of data to duplicate.

The Red Drives use two hard drives in a RAID 0 array, but they are still susceptible to violent movements or repetitive vibration such as a moving vehicle. This may result in 'dropped' or missing frames. The cameras will display a warning when this occurs. Red RAM drives are solid state RAM and overcome this problem, but at a financial cost. As with any tapeless format, the Red One data needs to be backed up (in three locations) on to hard drives, Blu-ray discs or data tape.

Can I record sound and time-code on the Red One?

The Red One can record up to 4 channels of un-compressed audio synced to picture. The camera has four mini XLR plugs as standard and we supply full size XLR adapters with the kits. The Red One can be fed jam-synced time-code from another camera or any other time-code device. When shooting multi-camera Red, we would recommend the use of an external Tri-level generator as the internal Red One clock has proved to be unreliable and prone to drifting. The cameras can be gen-locked in the usual manner.

How is the Red One powered? It can be powered on mains electricity or by the IDX battery kits supplied with the camera. The Red One takes a significant amount of time to boot up and therefore to save time on set, avoiding waiting several minutes to go through the boot-up sequence whenever a battery change is required, we supply a Switronix auto-switching battery holder that will mount two batteries simultaneously on the camera avoiding power-downs during a battery change. The battery plates are fitted with D-Tap connectors for powering any other 12v powered accessories such as monitors or radio focus kits.

How can I view the Red footage on set?

The Red One outputs down-converted video at 1080P allowing viewing on any HD monitor (we provide Panasonic 17" HD monitors as standard). We also supply a Redbyte down-convertor so that the 1080 HD video can be converted to standard definition for use on a Steadicam, crane, jib or for recording to a clamshell recorder or other logging device. The footage (including slomo) can be played back directly from the camera or your DIT, with a MAC computer on set and the Red Quicktime Codec installed, can also play back rushes directly from the RAW files.

Does the Red One require any optical filtration?

Unlike Sony or Panasonic cameras, which are designed to work in tungsten lighting conditions and require orange filters over the sensor when shooting outside, the Red One has a natively daylight balanced sensor. This will be more familiar to DOPs used to working on most common film stocks.

The camera has the ability to record without rebalancing the light source to daylight, but this results in increased noise levels when switched to 3200 Kelvin mode.

Shoot HD supplies our Red One kits with a Tiffen '80b' CTB filter for use when shooting under tungsten conditions, which corrects the colour temperature up to 5200 Kelvin - daylight. Having said that, for effect, we have seen some very pleasing rich and warm images which have been shot with uncorrected tungsten sources.

Is infra-red a problem on the Red One?

Unlike some other HD cameras on the market, the Red One 4k HD digital camera has no infra-red filter built in. Under normal circumstances, this isn't a problem. Daylight and even tungsten lighting gives off infra red light, as well as visible light. Ordinarily, the infra red is in a proportionately low quantity compared to the visible light, so such a small amount has no effect on the visible picture.

However, if you use Neutral Density filters (NDs above approx 0.6) then you are stopping down the amount of visible light reaching the camera's sensor, but you aren't reducing the amount of infra red. Therefore, proportionately there is more IR affecting the picture. The more NDs that you add the worse the problem gets. It will mostly affect the blacks, giving colour shifts, which will take time and money to correct in post-production grading.

Some hire companies will supply you with a dichroic infra-red filter (or some no IR filtration at all) which will cut out all of the spectrum above the visible light. This will work fine most of the time, but if you shoot with a wide lens (wider than 24mm), then the light at the edges of the filter is travelling through the dichroic coating at the wrong angle, rendering it ineffective and you will see the same colour shifts in the blacks, so this filter has limited application, and is not suitable for use with wider lenses.

Shoot HD believes that the proper solution isn't to use such a dichroic filter, so instead we supply two sets of IR filtration, which means that you're not restricted from shooting on wide lenses. Our solution is to provide a Tiffen Hotmirror which will cut out the top end of the IR spectrum only, plus a set of IR NDs which cut out the lower IR frequencies. This is a more expensive, but more flexible and comprehensive solution, leading to perfect colour reproduction when using ND filters.

What can I do with my rushes once they're stored, after the shoot?

Take a look on our Evolutions Post page of our website. We have a close working relationship with Evolutions, who have developed secure and quick processing and workflow solutions for the Red One. Click here or use the navigation at the top of the page.