4K, a world with plenty of possibilities. Essential guide for choosing a 4K camera.
By Carlos Medina, Audiovisual Technology Expert and Advisor
The professional environment of the audiovisual sector has it very clear that the only way in which contents created stand the test of time depends on the theme, type of content, and the technology use. The topic covered by this article deals with everything concerning today’s technology in image capture devices, i.e. cameras.
At present time, talking about technology and cameras necessarily implies referring to 4K, a technical parameter that has conquered all markets and areas relating video cameras, be it for inexperienced users, video amateurs or audiovisual professionals. And doubtless it has become the biggest advertising claim when selling an image (fixed or moving) capture device: state-of-the-art mobile phones, proconsumer video cameras, professional (cinema/TV) cameras, drones, action cameras… It seems that these devices are regarded as being from the past century if they do not have this 4K feature on their list of technical specifications and commercial name.
4K is a somewhat complex issue to grasp, so it is very advisable to take a look at what is going on at present in the areas of contribution and distribution (operations/dissemination/marketing in all modes and screens) of the 4K audiovisual product. Everything that makes possible the existence of 4K: technical parameters, encoders, compressors, international standards, hardware, software, manufacturing of equipment…
Therefore, the first thing to do is go back to the origin. The existing situation is the result of the birth of digital cinema, whose main goal would be to little by little achieve the same quality parameters as the cinema made out of celluloid (a 4-hole 35mm film, mainly). George Lucas was in 2002, with the film Star Wars: Episode II Attack of the Clones, the first one to “shoot cinema” with electronic images.
From 2015 onwards, all cinema is electronic-digital. But one of the biggest changes that this progress has brought about –which not many have noticed- is the blurring of separation lines within the audiovisual sector. We can now use the term “global media”, a digital ecosystem where cinema, TV, advertising, live events, internet, video, smartphones, computers… are there to create, inform, communicate, participate and enjoy, in a financially affordable way, quality content. And that means talking about 4K. All players involved in the audiovisual sector both advocate for and promote 4K: a novel way of producing content with technical quality and a technology revolution at anyone’s reach. This would not have been possible if cinema production had been kept in 35mm, as this is a complex process involving high financial/environmental costs. The ambition of many companies that electronic-digital images would make it to large cinema screens has paved the way to allow any of us to be able to have 4K images in devices as small as our mobile phones.
But, what is actually 4K as we mention it? Well, it depends. In the first place, when asked, most of us -i.e. users/consumers- would simply define it as good-quality images that are huge and really look great on the screen. This means that it is directly related with what -from a more technical point of view- we call image resolution and definition.
Resolution is the number of lines or pixels that comprise an image horizontally and vertically (height and width). Therefore, it is the amount of lines/pixels covering a space. That is why it is also known as spatial resolution. The higher the number of lines/pixels, the higher the level of detail, the better the image’s definition, more visual information and, therefore, the higher the quality.
Table 1 shows the difference between images having various resolutions that are most popular and have been generated by digital optical-electronic processes for TV and cinema, sorted out from lowest (SD) to highest (8K).
But if this question is asked in a professional environment, the answer is deeper and more complex. 4K is willing to improve image and sound. It is innovating in order to reach a more complete sensory experience. Therefore, although the differences found in spatial resolution are known, the changes are taking place in other parameters that are somewhat lesser known to the public and even to some professionals in the sector. It is now time to keep expanding our knowledge in order to make a good camera choice. For this purpose, we need to start introducing other technical aspects and essential innovations, so we can achieve improved images, both at recording and when viewing, that add up to spatial resolution of the 4K ecosystem:
– High Dynamic Range (HDR). The aim is having the capability of capturing and displaying a higher amount of grey levels by expanding the range of black and white hues. Achieving a greater realism in contrast and exposure between the areas of an image.
– Wide Color Gamut (WCG). Basically, the aim here is getting the electronic media to come as close as possible to the color palette that the human eye is capable of “seeing”. In this case they are wider gamuts or color spaces, as defined by the standards used in cinema or TV. The ultimate goal: Using a wide color space (thence the WCG acronym). IT means going from the BT.709 gamut in the FHD environment (capable of displaying only about 35% of colors that the human eye is able to perceive) to DCI P3/YXZ, that covers approximately 54% and to the BT.2020 gamut, that covers nearly 76% of them. And with a view to the future, we will have to follow closely the implementation of the new color space as defined by the Hollywood Academy, also known as Academy Color Encoding System (ACES: AP0/ AP1/CC/Proxy).
– High frame rate. This is recording and playing a higher number of frames per second (fps) or images per second (ips). It is also associated to frequency, Hz. It is known as time resolution as well. This will offer us higher image stability, without any unnecessary flicker and greater smoothness in images in motion. We all know that analogue cinema used to be shot at 24 fps and also that SDTV PAL is at 25 ips (30 ips in NTSC). And so, 4K content goes for new HFRs, as for example the film The Hobbit: An Unexpected Journey (Peter Jackson, 2012) was a project conceived in 48 fps and spectacular differences were noticeable in the big screen. This progress is related to VFR, or Variable Frame Rate.
– Sampling and quantification. It takes place in the image digitalization process (and audio as well) in regard to the taking of samples from the signal, in its respective RGB in the case of video. It means increasing bit depth or color depth. This is, a higher quantification level means increasing the number of bits per sample. And higher levels in each sample entail more information, and this means being closer to analogue reality. This aspect is very well appreciated for color correction and post-production as well as for video/audio effects. These are parameters that are very important, that define the quality of the digitalized records in 4K productions, which are deemed advisable from 10-bit onwards.
– Surround or immersive audio. Entails developing sound systems that provide a third dimension and give deeper spatial depth in audio playback when it comes from different areas (because of the speaker placement and design of sound distribution in audio channel setup). The 4K ecosystem means going from 2.0 to 5.1 or higher. But this parameter is not decisive when it comes to choosing a camera model.
Therefore, bearing these issues in mind, we are now in a position to take a first approach to models that manufacturers are offering in order to choose a UHD/4K (and some with higher resolutions) in comparative terms on resolution, progressive images and the most panoramic aspect ratios that comprise various sectors and environments in the audiovisual industry.
As for mobile phones, worth noting are GOOGLE Pixel 4 XL and Pixel 3 (3 XL, 3a and 3aXL), ONE PLUS 7 Pro (Plus 7T, Plus 7T Pro), HUAWEI P30 (P30 Pro), IPHONE 11 (11Pro and 11Pro Max), XIAOMI Mi Note 10, SONY Xperia 5 and SAMSUNG Galaxy S10 (S10e and S10 Plus) as well as Galaxy Note 10+5G, being this manufacturer capable of recording 8K with model Note 20 (20 Ultra 5G 8K).
In non-professional video cameras, FHD are still on top, although we now find some manufacturers that offer the possibility of recording in UHD, such as SONY FDR (AX43, AX100 and AX700), CANON Legria (GX10, HF-G26 and HF-R806), XA 40, JVC GZ-RY980, PANASONIC HC-X1E and HC-V180EC.
In the scene of professional photographic cameras, which have made the move from fixed image capture (photography) to the possibility of recording 4K video, there is a really wide offering for users. The following models are worth mentioning: PANASONIC Lumix (G7, GX8, GH5 and GH4), OLYMPUS OM-D E -M10 Mark III, SIGMA FP45 UHD, CANON EOS 77D, EOS 1DC, EOS 5D -Mark IV and III-, NIKON D7500, FUJIFILM X-T2, SONY a6500 and Alpha A7S II.
Within the TV sector, spanning several types of camera for studio production modes, EFP and ENG, the following manufacturers are to be highlighted: CANON XC15 UHD, PANASONIC (AK-UC4000, AK-UC3300, AJ-CX4000GJ, AG-CX350, AG-CX10, AG-UX90, AG-AC30, DVX 200, HC-X1), JVC (GY-LS300 UHD, GY-HC550, GY-HM170), SONY (NEX-FS700 EK UHD, PXW-Z750, PXW-Z450, PXW-Z90, PXW-Z150, HDC-5500, HDC 3500, HDC-4800) and the LDX 86 series by GRASS VALLEY.
Digital cinema is the environment where cameras having resolutions higher than 4G can be found and where there is a really strong competition by all manufacturers in order to position their models. Therefore, we find here manufacturers such as ARRI (Alexa Mini and Amira Premium), RED (Ranger Monstro 8K; Weapon Monstro 8K, Epic-W 8K Helium, Epic Dragon 6K, Gemini 5K and Raven), and BLACKMAGIC (Pocket Cinema 6K; URSA Mini Pro 12K). And also proposals from PANASONIC (AU-EVA1 4K; AU-V35C1G Varicam 4K; AU-VREC1G Varicam), CANON EOS (C700, C500 Mark II 6K; C200 4K; C300 Mark II 4K), SONY (VENICE, PXW-FX9 6K; PXW-FS5M2K 4K; PXW-FS7M2K 4K; PMW-F5, PMW-F55) and PHANTOM FLEX 4K.
As for drone-mounted 4K cameras, the leading manufacturer in this area must be mentioned: DJI with models such as Mavic Air 2, Phantom 4 and Inspire 1; or other brands such as: YUNEEC Q500, ROBOTICS 3DR, HUBSAN Zino Pro, XIAOMI FIMI X8 SE and Mi Drone 4K, PARROT Anafi, or even AUTEl EVO II 8K, the latter even allowing 8K recording.
In the market of video cameras that are regarded as sports or action cameras, models allowing 4K recording can be found: GOPRO Hero7 and Hero 8; SK8, DJI Osmo Action and Osmo Pocket, Xiaomi Yi Plus and Mijia, SJCAM SJ8 y SJ7, SONY FDR-X3000 and RX0 II, or INSTA 360 One X.
To properly close this guide, when dealing with image capture devices, other kinds of features must be taken into account when considering cameras in order to adapt as best as possible to the needs and work modes when it comes to recording.
First of all, if the device will allow us to work with different optics and focal distances (fixed or interchangeable). It is crucial that both design and construction of elements and optical groups are ready for 4K images.
Second, the size of the capture sensor: the larger the sensitive surface, the better the response level achieved, this resulting in more satisfactory images. Therefore all kinds of sizes exist, the biggest being Full Frame, Super 35, APS-H, APS-C, Micro Four Hhirds 4/3″, 1″, 1/1.7″, 1/2.3″, 1/3.2″, 1/3.6″, 1/4″, amongst others.
In third place, the camera’s operation. In this sense, everything that the camera has internally must be taken into account: image stabilizers, focus assistance, automatisms, exposure assistance, changes in sensitivity and gain, controls for technical adjustment of images, black and white balancing… amongst other; and also what is shown outside in regard to design and placement of buttons and access menus to facilitate recording routines, microphone, type of display, grips… In this last aspect, the size of the camera’s body is important, because the smaller ones only have what is essential for operation.
Fourth, we must take into account what is termed as recording media, this is, the type of media used by the camera to store 4K videos. Thus, we have the manufacturer’s proprietary solid-state memory cards, as it is the case with ARRI or RED ONE, and even media as unique as P2 cards (PANASONIC) or SxS cards (SONY), or other more widespread media amongst users, such as SDHC/SDXC and Compact Flash cards.
In fifth place, the camera’s weight and size. Although the trend in the market is for cameras that are as ‘mini’ and as light as possible, we do have to bear in mind the camera’s stability, balance and robustness for a correct operation. Nowadays, technological innovations and newly developed construction materials have indeed helped to come up with cameras that are increasingly less heavy and featuring designs based on modular approaches.
Sixth, and of no lesser importance, is the price of the camera to use. Currently we find a truly wide range of prices and we can only recommend to carefully consider the options to make it within the required budget, the type of production and the number of recording sessions we are going to do.
As a conclusion, we must say that 4K cameras are firmly established in all kinds of markets concerning capture equipment: smartphones, handheld video cameras, TV cameras, cinema cameras; and also in more specific environments such as drones, action… Although the truth is that we have not yet reached a real ecosystem comprising production, distribution and marketing of 4K content, as other factors have set the pace in regard to implementation in society, from continued technological progress to the economic situation in which they take place.
The term 4K appears in spectacular advertising and marketing campaigns as a distinctive ‘new and good’ landmark for the purchase of equipment, both for recording (photo and video cameras) as for enjoying content on TV screens, as well as when it comes to signing up for TV or internet services. It is of vital importance to know the actual resolution of equipment in order not to buy a ‘pig in a poke’: a pseudo 4K, just UHD or if there is just no 4K.
This could cast a shadow over full implementation of 4K amongst the public. Therefore, 4K content will always be available provided two essential conditions are met. First of all, that the players in the audiovisual industry standardize the whole process by means of technical decisions enabling maintenance of 4K in a simple, economic, standard, synchronized manner in all areas, as this must come as a direct solution that will be as global as possible. And number two deals with the decision of users/consumers to be willing to purchase, enjoy and consume 4K (or at least UHDTV) content. In principle, we assume this is the case, in light of the considerable benefits.
This 4K panorama, which has been for several years now present in all the audiovisual industry’s trade shows and events, must gradually address some other unknowns that affect to contribution and distribution of contents, so viewers will easily assimilate the changes. A number of conundrums dealing with bandwidth, production and exploitation formats, displays, connectivity of equipment, media and storage systems, audio and even viewer tastes and demands.
Having in mind all these requirements and decisions, as mentioned above, which will better shape the 4K video camera scene, we can say that any user or professional of images can definitely find a whole world with plenty of possibilities when it comes to choosing a 4k camera.