Digital cinematography is the process of capturing motion pictures as digital images, rather than on film. Digital capture may occur on tape, hard disks, flash memory, or other media which can record digital data. As digital technology has improved, this practice has become increasingly common. Many mainstream Hollywood movies now are shot partly or fully digitally.This is a technique of shooting on film, scanning the film into digital format for various reasons, and ‘recording’ back to film for printing.  So you begin and end on film with an intermediate stage that is digital.  Initially, this technology was reserved for when it was needed the most when the shot required extensive computer manipulation and other effects digitally.  Eventually as the costs dropped and the process became more streamlined, more common optical effects could be done digitally instead.Finally, some filmmakers started using digital intermediate technology for changing the colors in a shot, giving them access to the far more powerful color-correction tools than available with simple 3-color printing.  With standard printing, you could simply make a shot  redder or bluer, for example.  However, with digital color correction, you could change the contrast and black levels, you could do mid-shot corrections, you could manipulate the colors of some areas of the frame but not the others and so on.  At first, only select scenes received the DI treatment, but after a while entire films were being color corrected this way.  The basic steps in DI technology are as follows:Shoot on film to get the best image, which of course is processed in a lab.Scanning:  The original film is scanned into a digital format. Color correction and other effects:  All kinds of digital manipulations are done in this stage.  It also includes dust removal, checked for scratches and any other correction that may be necessary.Recording:  This is a reverse process of scanning where the digital information is back on celluloid, usually to a 35mm internegative (or dupe negative).Release prints:  Married prints are made from this dupe negative along with the sound negative for theatrical release. The first step of using celluloid film can be done away with, although with some compromise in quality, by using high-end digital cameras.  A minimum scanning resolution of 4000 pixels horizontally (the number of pixels vertically depends on the aspect ratio) is considered necessary to capture all the information on a 35mm motion picture frame.  This is referred to as ‘4k’ resolution.  However, a half-resolution scan of 2000 pixels across (‘2k’) is considered adequate for a number of practical purposes; 2K scans are faster and more affordable, although that will change as technology keeps improving.  At this time, the majority of DI work has been done on 2k resolution.  While this is somewhat a compromise for the 35mm frame, it is completely adequate for 16mm frame.    

Many vendors have brought products to market, including traditional film camera vendors like Arri and Panavision, as well as new vendors like RED and Silicon Imaging, and companies which have traditionally focused on consumer and broadcast video equipment, like Sony and Panasonic.The benefits and drawbacks of digital vs. film acquisition are still debated, but digital cinematography cameras sales have surpassed mechanical cameras in the classic 35 mm format.  Digital cinematography's acceptance was cemented when Slumdog Millionaire became the first movie shot mainly in digital to be awarded the Academy Award for Best Cinematography.[1]

Sensors

Digital cinematography cameras capture images using CMOS or CCD sensors, usually in one of two arrangements.High-end cameras designed specifically for the digital cinematography market often use a single sensor (much like digital photo cameras), with dimensions similar in size to a 35 mm film frame or even (as with the Vision 65) a 65 mm film frame. An image can be projected onto a single large sensor exactly the same way it can be projected onto a film frame, so cameras with this design can be made with PL, PV and similar mounts, in order to use the wide range of existing high-end cinematography lenses available. Their large sensors also let these cameras achieve the same shallow depth of field as 35 or 65 mm motion picture film cameras, which is important because many cinematographers consider selective focus an essential visual tool.Some professional digital cinema cameras which have been designed to satisfy professional  DoPs  include:

Sony CineAlta Thomson Viper Silicon Imaging SI-2K Panavision Genesis Arriflex D-20 Dalsa Origin Red One Panasonic VariCam

For more on this http://en.wikipedia.org/wiki/Digital_cinematography_cameras

Hollywood

On higher budget productions, the direct cost advantages of digital cinematography are not as significant in relation to the total budget, primarily because the costs imposed by working with film are not the only major expenses for such productions.

Other factors, such as improved speed, security and the ability to connect to the postproduction already while shooting are also important factors which often play a role when A-budgets are shot digitally and not mechanically. Skipping developing the negative, linking live via satellite or data networks, on set backups of the shots and immediate availability of high-quality dailies on blu-ray, hdcam or file-base have become commonplace for many directors and Directors of Photography.Recent films, such as Sin City and Superman Returns, both shot on digital tape, had budgets of $40 million and close to $200 million respectively. The cost savings, probably in the range of several hundred thousand to over a million dollars, are not negligible for today's producers.The mentioned security and speed advantages are an important reason to shoot digitally for many producers. The ability to check expensive shots at once on set, the possibility to backup and copy shots lossless directly at the set, the immediate transfer to postproduction as well as remote viewing by directors allow massive cost- and timesavings and reduce risks.Rick McCallum, a producer on Star Wars Episode II: Attack of the Clones, has commented that the production spent $16,000 for 220 hours of digital tape, where a comparable amount of film would have cost $1.8 million. With disk-basing systems as the Red one or the SI 2K, the cost would be even lower, and exact backups can be stored at different locations on different media as well. However, this does not necessarily indicate the actual cost savings percentage, as the very low incremental cost of shooting additional footage may encourage filmmakers to use far higher shooting ratios with digital. Lower shooting ratios, no matter if with mechanical or digital cameras, may save time in editing, or may make the team miss interesting shots.Digital versus filmQuality:  The quality of film is still considered as the ultimate though the advancements in digital medium are rapidly progressing.Cost:  The cost of film and processing is a disadvantage with film.  Digital technology scores over film on this aspect.  Besides films are not reusable and also you pay for processing all the NG shots also.  In digital medium, it is possible to delete the shots on the spot if it is felt that they are not usable at all.   High quality film cameras are less complicated and therefore less expensive. The major expenses are ongoing film and processing costs.  Digital cameras are comparatively expensive.  Performance:  The flexibility that film offers to a DoP is not available on digital cameras.  For example, the contrast handling capabilities (highlights versus shadows) are wider in film than digital.  Film is more ‘forgiving.’    Digital scores over film as it is instant.  One has to wait for film to be processed and printed and then use a projector to view the visuals.  Archiving:  Feature films which are almost a century old are still in good condition even now.  Some decline in quality can be corrected by using the

latest digital technology.  However, digital images are just a few decades old and their stability is yet to be proved.  Some films shot on digital medium have been printed on to celluloid as backup for archival purposes.  Digital is always stuck in whatever quality you shot it. Digital or video has nothing to rescan. What you got it is all you're going to get. This is why Hollywood shoots movies, and even the better TV series, on film. 10 or 50 years from now they can still get better and better images by rescanning them. Go watch the latest DVD of The Wizard of Oz shot on film in 1939. They simply went to the vault and rescanned the film with modern technology.PERMANENCE: Film does not erase itself. Film does not become unreadable for no reason. It doesn't have file compatibility problems. Traditional black and white film and prints will outlast any of us.COST: Digital cameras are very, very expensive for what they do. They become obsolete in a year, unlike film cameras in which even 50 year old cameras and lenses are in use daily.Film:

Film is still higher in resolutionCameras are generally heavierFilm can take up a lot of spaceFilm is a continuing costFilm must be developed before viewing

DigitalHigher initial costCan easily lose detail in whites and blacksCameras are generally lighterOne memory card can store more images than a dozen rolls of filmImages can be viewed immediatelyYou can edit your imagesOnly print the images you like

   Digital cinema refers to the use of digital technology to distribute and project motion pictures. A movie can be distributed via hard drives, optical disks or satellite and projected using a digital projector instead of a conventional film projector. Digital cinema is distinct from high-definition television and in particular, is not dependent on using television or HDTV standards, aspect ratios, or frame rates. Digital projectors capable of 2K resolution began deploying in 2005, and since 2006, the pace has accelerated. (2K refers to images with 2048 horizontal pixel resolution.)Savings in distributionDigital distribution of movies has the potential to save money for film distributors. A single film print can cost around US$1200 (or $30,000 for a 1-

time print of an 80-minute feature[8]), so making 4,000 prints for a wide-release movie might cost $5 million. In contrast, at the maximum 250 megabit-per-second data rate (as defined by DCI for digital cinema), a typical feature-length movie could fit comfortably on an off the shelf 300 GB hard drive—which sell for as little as $40 (retail price, volume prices are even lower) and can even be returned to the distributor for reuse after a movie's run. With several hundred movies distributed every year, industry savings could potentially reach $1 billion or more.

Greater protection for content

A last incentive for copyright holders for digital distribution is the possibility of greater protection against piracy. With traditional film prints, distributors typically stagger the film's release in various markets, shipping the film prints around the globe. In the subsequent markets, pirated copies of a film (i.e. a cam) may be available before the movie is released in that market. A simultaneous worldwide release would mitigate this problem to some degree. Simultaneous worldwide releases on film have been used on The Da Vinci Code, Lord of the Rings: Return of the King, Star Wars: Revenge of the Sith, Charlie's Angels: Full Throttle and Mission: Impossible III amongst others. With digital distribution, a simultaneous worldwide release would not cost significantly more than a staggered release.For more info visit http://en.wikipedia.org/wiki/Digital_cinema1.     What is video assist and how has it revolutionized film making?

Video assist is a system used in filmmaking which allows filmmakers to view a video version of a take while it is being filmed.Originally a small device, called the video tap, was installed inside a movie camera that allows (with the addition of a monitor) the director to see approximately the same view as the camera operator, and thus ensure that the film is being shot and framed as desired. This is done by using a small chip (similar to ones in consumer camcorders) inside the viewfinder.  The chip, together with its electronics, lens system and mounting hardware is the video tap, and was commonly called video assist until the video assist industry grown large.  Camera gear like the jib was possible only with the invention of VAs.While a very simple video assist equipment is only capable of showing a live image, the modern VA equipment does much more than that. The image feed from cameras are recorded onto an inexpensive medium (usually MiniDV or Hi8) and nowadays on hard disks. The VA operator keeps a precise log about which take was recorded where, noting the time code or file name. He or she is then able to play back any shot in a short time, even right after the shot. This is essential for a director to show actors where to change their moves, or to recheck dialogue lines,

and also helps the Script Supervisor. It is very easy to check shooting angles, correct overlaps, and time camera or stunt actions. The VA recorder can usually simulate the under-cranking or over-cranking of the camera, and speed up or slow down the action. Ramps (speed changes in the shot) can be shown also. The Video Assist gear often includes a portable editing system (usually a laptop with a digitizing box and an editing software), so rough cuts can be made by the VA operator right on set. A portable video mixer is useful to check out key, blends or pre-visualize visual effects. A video printer is often used to print out pictures or hard copies of sets, camera angles or faces for art designers, make-up artists, and storyboard artists.  Sound engineers and make-up usually requests a separate, live-only feed to know what's happening in front of the cameras and so don't need to continuously pop in and out of set. 2nd units or splinter units shooting extra shots or b-roll can take away small VA recorders to record their own footage, which is then loaded into the main unit archive so it can be watched and checked against main unit footage.

Television:  A television image is formed by scanning the optical image with an electronic beam using a cathode ray tube (CRT).  The number of horizontal lines in NTSC is 525 and is projected at 30 frames/sec.  PAL system has 25 frames and 625 lines per frame.   The image is reproduced in a reverse fashion where the electronic signals scan the phosphor-coated television screen and the screen glows proportional to the strength of the signal thus reproducing the original image.   CRTs have now been replaced with CCDs (charge-coupled device).  Television sets are available in both CRT and LCD forms now.Interlaced scanning:  The lines scanned for video (625 or 525) is not done one by one but done alternately.  In other words the odd lines are scanned first and then the even lines.  This was done in the earlier days of television to overcome the problem of flicker.  It continues even now as CRT monitors can display flicker-free images only with interlaced scanning.  The system which uses interlaced scanning is usually referred to as 525i or 625i.Progressive scanning.  This is a method in which the lines are scanned one after the other i.e., 1,2,3,4,5, and so on.  LCD monitors are capable of playing back progressive images without any flicker.  In progressive mode, it is usually referred to as 525p or 625p.High-definition TV:  By increasing the number of lines, it is possible to get sharper images and thus was born the high-def TV.  High definition can be 720 lines (referred to as 720i  or 720p) or it can be 1080 i or p (sometimes referred to as full high definition) and is gradually replacing the older system of NTSC and PAL.   Major events are now covered on high-def format and the recent

Commonwealth Games held in Delhi as well as the cricket world cup were covered on HD.  The world has now moved on to the HD platform.  Distribution of TV signals:

1)     The terrestrial method:  This is the oldest and the first method of TV transmission. In this method, a transmitting antenna from the TV studio radiates the signals.  The reach of the signals depends on the height of the transmitter and the strength of the signal.  A typical 10 KW transmitter has a radius of about 120 kms.  The receiver uses an antenna on the rooftop which is connected to the TV to receive the transmission.  Only Doordarshan uses terrestrial transmission.  The TV signals are not consistent and the picture quality varies.  Further, the quality drops as the distance from the transmitter to the receiver increases.  A major drawback in this method is that only one channel can be aired.  This method can only be free-to-air.  Only a limited area can be covered and a very expensive method of transmission. 2)    Cable TV:  In this method, the TV signals are beamed to a satellite and cable operators download the encoded signals.  In turn, they distribute the signals to a limited area in their locality using coaxial cables.  Advantages:  a) Several channels can be beamed simultaneously.b) The cable operator collects subscription and thus it is possible to have pay channels.c) The quality is better than terrestrial transmission.Disadvantages:

a)     The quality of the signals are good only in the prime band and gradually the quality gets from bad to worse. b)    Cables have to be run from the operator to each subscriber.  Cables have to be maintained.c)     A power outage at the operator results in total shutdown of all channels.  Also, amplifiers have to be set up in order to boost the signal strength to subscribers who are far off.

A new method of cable TV dissemination in the form of digital encoder/decoder has now solved the problem of the quality and now signals across all the channels are equally good.DTH:  Direct to home:  This is the latest technology through which signals are beamed to the satellite and each subscriber is provided with a small dish which is mounted on the rooftop.  The quality of the signal is extremely good across all channels.  It is also possible to air HD TV using DTH technology.Advantages:

a)      Very good picture quality.b)    There is no interference as the signal is directly received from the satellite. c)     Revenue is generated from each subscriber as he has to pay every month.d)    The subscriber has a choice to choose and pay for only those channels that he wants.e)     Possible to have some interactive channels too.

Disadvantages:a)     Under vey cloudy conditions, there is no signal and hence all channels are blocked.b)     All channels are not available on any of the DTH platforms as some packages are found in one operator but not in another.