The best part of digital filmmaking is that it can be highly innovative, and of course, such innovation lies in the imagination of the beholder! Leapfrogging technologies and the ever expanding internet with its plethora of options has been instrumental in bringing about a seachange in the way films are made.

Today, I am talking about a do-it-yourself collaborative filmmaking website called RootClip.com, where the creative team make a short video clip or "Rootclip" to start the story. Amateur filmmakers watch their video, then shoot their own rendition of what should happen next in less than 2 minutes. The result is an entire short film made by amateur filmmakers.



I think it's pretty exciting. Their last film actually debuted at the Travese City Film Festival. ust say this has got a lot of potential.

One of the greatest pieces of advice I have ever heard is from Robert Rodriguez. He said you should learn to trust your instincts. When you imagine a film in your head and you see the shots, you may not be able to write a thesis to back up why you have gone with, say a POV, rather than a tracking mid shot from behind the actor. Hopefully you would have watched enough good movies to have filmmaking running through your blood. If this is the case, trust those instincts. Even if it means you'll make mistakes, it can only better you and your inate ability to get the right shot. That said, here ar a few basic things that you can pickup in any text on filmmaking:

• Low shots shooting up at a character give that character a sense of being important and powerful.
• Higher shots, shooting down onto an actor give that character a sense of being unimportant and weak.
• If you shoot from a 90 degree angle dead onto a character's face (i.e. facing the side of the actor) the audience will not make much of an emotional connection with them. It will feel sterile and cold.
• Bringing the camera around now, the more you move towards shooting the actor's face on, the more of an emotional connection the audience will make.
• Likewise the closer the camera/audience is to a character, the greater the connection.
• Scenes where emotions rise through a scene often work best starting out further away and cutting up until close ups and even extreme close ups. You can also handle the emotional charge on one character by slowly moving the camera towards them.
• POV shots help put the audience into a character and the strongest ways of creating audience-character connections
• Use a wide establishing shot at the beginning of each scene, so the audience has an idea of the spatial relationships between the actors and their envirnment. The only time you do not do this is when you want to portray to the audience that the characters themselves do not know where they are (e.g. beginning of 28 days later).
• Shots from directly behind a character are another way of doing this, but allow the audience to see more.
• Remember, films have rhythm. Imagine a frenzied dog attack scene, or a fight scene. The editing in these films will be incredibly fast paced. Now think of a scene where two people are sitting in a restaurant, getting to know each other. The cuts will tend to match the conversation. If the script dictates that an argument should occur, the speed of the editing will increase also.
• Remember the importance of good sound and how it can add so much to a scene. Check out the hammer drop at the end of my short film Origins to see an example.
• If you intend to cut directly from a wide to a medium, or a medium to a CU, etc, without cutting away, a good trick is to shoot them all from slightly different angles. This will help you hide any action continuity discrepancies.
• Familiarise yourself with the "Line of action." This is an imaginary line that can be seen as a 'stage' in theatre. When you go to watch a play, think how the audience is positioned. It is always to one side of the actors. This means that if actor A stands on the left hand side of the stage, and actor B stands on the right hand side of the stage, actor A will always be looking to his right, and actor B will always be looking to his left. If this were a film, this would be valid, as any cuts to either actor would always result in them looking at each other. If you cut to actor A, jumped the line of action, then cut to actor B from the other side of the stage, you would see actor A looking right, then actor B looking right. This is an extreme example, but you would surprised how many directors have jumped the line by accident - and it causes a jolt to a lot of viewers. A more subtle example is one of my first short films - Opportunity Knocks. In this film Actor A and Actor B are talking in a hallway. Actor A and Actor B both look to their left. This is because the camera jumped the line of action. A lot of people didn't notice it, but then this is as about as subtle as breaking the rule gets. Always imagine your shots as being taken from the audience area at a play, and that will help you to avoid breaking this rule. The one exception to the rule is car scenes, as audiences have become used to the way they work (background moving to the right in one shot, and moving to the left in the next as camera jumps from one actor to another)

Okay - so we get to the big day. If this is your first time with a crew, you will struggle. It can be a little overwhelming. It's like when you first start filming in public - you'll feel awkward and not want to be there. But after you gain some experience, members of the public won't even phase you - and in just the same way, experience on set will ease you into working with the team.

Here are some pointers for production:

• Remember that first shot - keep it simple
• Keep lots of refreshments on hand - it might be a good idea to buy lots of sandwiches, chocolate bars, cans of drink, etc and put them in a big cardboard box for people to access.
• Remember to find out what people like - some people are vegetarians, for example.
• Have regular breaks, but do not break up the impetus of the shoot. Consult the crew - they might be willing to get a few more shots done before a break. I had a break after each camera set-up. The lights are so intense, that when you turn them off to change set-up, everyone will need to have a breather.
• Stick to the shot list. Don't get distracted.
• Do not use 'auto' settings for exposure, focus, etc. Your Cameraman and.or DoP will set these. There is nothing more embaressing than having the autofocus jump all over the place in a scene.

Here is an equipment list that you should consult before going on set:

• Camera(s)
• Camera Batteries (Fully Charged) + charger
• Leads to plug camera(s) into power sockets
• Boom Pole
• Boom Mic, with accessories
• Relevant sound recording device + leads + accessories
• Sound Capture Device (E.G. DAT Machine) Batteries (Fully Charged) + charger
• Gaffer Tape
• Scissors
• White Balance Card/Paper
• Extension Cables
• Lighting Gels, Diffusion Materials and Black Card
• Crocodile Clips (for clipping gels, diffusion material to lights)
• Industrial Gloves (so you don't burn yourself moving lights)
• Box of food and refreshments
• Chalk and a Clapperboard
• Box of DV Tapes
• Box of minidisc/DAT tapes (assuming you use either)
• Mobile Phones with numbers of local taxi firms - just remember to keep them switched off during takes

Previous to a day's shoot, you should have discussed with your DoP and cameraman the various set-ups you want to shoot. When you arrive on an interior location, you normaly follow the following process:

1. The Crew move all unnecessary furniture, etc out of the location, or to a safe place inside the location that will not obstruct the cast and crew.
2. The DoP and Gaffer begin setting up lights. Any extra work the DoP wants done is then carried out by the gaffer, such as gaffer-taping black card over windows. This is done so that changes in natural light cannot obstruct the continuity of the shots in your film. If your shots are supposed to have daylight in them, the DoP will probably use a powerful light and some blue gels to simulate it. They will give you a list of things they need in advance after discussing your storyboard with you. I was asked to provide blue gels, diffusion material, some reflectors (a cheap relector can be cardboard with tin-foil glued to it), and a flag (used for blocking out light - a cheap way to make one is a large chunk of hardboard painted black).
3. When the set is lit, the director will walk the actors through the action. You will normally do a few dry runs and mould the performances as you go. The Sound Recordist will also record approximately 60 seconds of general background ambience which can then be used to make the editing between dialogue seemless and fill in gaps between dialogue. This is called a Buzz Track.
4. When you are ready to do a take, firstly ensure all the cast and crew are aware you are going for a take and are 100% sure of their job during the take.
5. Before any action, you instruct the cameras and sound to roll. Your DoP/Cameraman and Sound Recordist will both then acknowledge that cameras and sound are rolling. At this point, the Production Assistant (PA) will move into shot with the clapperboard clearly readable, and read out the scene number, shot number and take number, and then clap the clapperboard. It is then down to you to shout action. Wait at least 5 seconds after the clap before you do so. There are a number of different types of actions that could occur. For example, camera action, background action and main action (involving actors). If the shot begins with a slow pan inside a packed basketball stadium, and ends on two people in the foreground commenting on the performance, then you firstly shout 'background action' to ensure that the crowd and players are doing what they are supposed to do (cheer, wave arms, play ball, etc). Then you would shout 'camera action' to begin the pan. When the two foreground actors are in frame, simply shout 'action' and they will begin as directed.
6. If any of your actors make mistakes during their action, try and get them to pick-up their lines, as it saves having to do another take. Also, if an actor makes a mistake at the beginning or middle of a take, you will lose all the rest of a potentially good take if you shout 'cut'. Simply inform them of the mistake, then get them to continue. This will happen when there is bad sound too. The sound recordist will tell everyone to halt if there is an unwanted noise being picked up on his earphones.
7. When the take is complete, simply shout 'cut'. If you did not get a clap at the beginning, then tell the actors to halt action, and then get the PA to come into shot and clap, then shout cut. Some people hold the clapper board upside down for the clap when doing claps at the end of a take. Let the DV tape run at least 5 seconds after the actions has halted before you shout 'cut'.
8. Your sound recordist will have a sound log, which they will fill out to say which takes had clean sound, and which ones had problems. All a log really needs to tell you is the shot number, take number, and description. It is desirable that the same should be done for the picture. When I filmed Mnemosyne, sometimes a bird would come into shot at the end of a take, so the camerman would make a note of this. It's good to know things like this, as the rest of the take was clean and could be used in editing.
9. It's up to you how many takes you go for. I like to have at least two good takes before I move to the next shot.

Before I launch into my production section, here's a little about the crew you might require for a low-budget film:

EXECUTIVE PRODUCER, PRODUCER, WRITER, DIRECTOR AND EDITOR

For a low budget film, all of these are normally you! You financed the film and are the top dog (Executive Producer), you will plan and oversee the production (Producer). You wrote the film (Writer) and will direct it (Director) and most likely edit it too (Editor), although you can post on shootingpeople.org for producers, editors, writers, etc.

For my film I had two additional producers come in. These were my good friends Hakan Besim and Stuart Folley. They helped not only with the planning and location scouting, but also with the production itself.

DIRECTOR OF PHOTOGRAPHY

This person works with the director to make sure that, visually, the film meets the director's vision. The DoP will light the sets and help with camera-setup and even camera-work. Everything they do comes down to making the film feel a certain way. They will make numerous suggestions on how the set can be lit but will first want you to 'walk them' through the action so they can decide how to best set up the lights to do things like cast appropriate shadows or produce effects appropriate to the atmosphere the director wishes to convey. On my film my DoP used 3 redheads, 2 lilliputs and natural light in order to produce the mood I wanted.

SOUND RECORDIST

This chap, who normally brings his own earphones, will monitor the recording of the sound, whether it is directly into the camcorder, or into a minidisc or DAT. They will make recommendations on what kinds of microphones they require, but ultimately your budget and flexibility will decide that. My Sound Recordist used a Seinheisser ME66/67 microphone and a DAT machine. In most circumstances, you, the producer, will have to rent a DAT machine as the sound recordist may not own one. DAT machines have an in-built pre-amp which means you can crank up the sound if it is too weak.

BOOM SWINGER

The boom swinger is not always required unless there is a lot of shots where different people are speaking. Normally a sound recordist can swing with slow paced dialogue himself. If this happens, have someone use an agreed signal so he knows where to swing the boom next.

CAMERA OPERATOR

I am the kind of director that loves to do this myself, and when I am absolutely unable to do this I have my DoP step in. For exteriors I had a special cameraman do this work. For interiors, the role was shared between myself and the DoP. I guess it all depends on how much interaction you are going to be doing with your actors, and, of course, how many cameras you have on set. For some shots, there is no replacing a good cameraman.

GAFFERS

The DoP may require someone to help them set the lights up, and move things around for them. The Gaffer will normally do things like gaffer-tape blackout card to windows and clip gels to lights. On my set this role was always filled by someone else. Either I would do it, or the sound recordist or another producer would step in. I enjoy working in small teams where everyone is busy and energised.

DRIVERS

If you are going to be transporting a lot of crew and equipment about, always make sure you have a car or two! On my film, this role was filled by either actors, producers or friends.

MAKE-UP

Remember that it is a good idea for all actors to wear a base, even if they are not going to have any fake blood, etc. Otherwise they will appear hideos under the powerful lighting. If there is going to be no special make-up, learn how to apply base yourself.

STILLS PHOTOGRAPHER

Some directors do this themselves. These guys get good behind the scenes photographs as well as production photographs. The production photographs are to be used in the press pack for your film, so normally the actors pose after the action for these and pretend they are still in action.

PRODUCTION ASSISTANT

Person who claps the clapperboard and does general work that needs doing - a real workhorse. Gaffer can do this too!

THE ULTIMATE SKELETON CREW

Ultimately, I have found the smallest crew that you can shoot with is:

• Director
• DoP experienced in camera operation
• Sound Recordist
• Gaffer
• PA

When the film is at a rough-cut stage, you will need to recruit the services of the following crew. I recommend recruiting them as early as possible - i.e. in the pre-production phase:

• Sound Design and Foley
• Composer

Some sound recordists do the whole lot! Most composers on shootingpeople.org will work in exchange for a credit.

You could shoot without a crew like Robert Rodriguez did when he made El Mariachi, but digital is less forgiving than film. It's possible: move the lights around yourself until it looks good. Record the sound and dialogue afterwards using the camcorder sound as a guide-track. Shane Carruth (Winner of Grand Jury Prize at Sundance 2004 for PRIMER) taught himself how to DoP out of books and trial and error. yep, it's definitely possible, but a big, big risk.

Apparently you are supposed to have someone on set who has a recognised qualification in Health and Safety up to a certain level (which may vary from country to country). It's up to you what you do here. I know I wouldn't want to abandon, or postpone my film just because I couldn't get someone of that description to be on set every day. Would you? I find common sense prevails in certain situations where following some 'rule' is the status quo.

Before you worry about crewing your film, however, there is the small matter of the pre-production. You have a great script and now you must work on turning it into a film. Here the most important thing is: PLAN PLAN PLAN!!! One mistake I made was selecting my locations without consulting a sound recordist. It doesn't help when you are trying to shoot a dialogue scene in an alleged deserted town but you happen to be beside a busy motorway! You can probably select locations without a sound recordist, but if you do it is not simply a question of going to the location at the time you plan to shoot and seeing if it sounds OKAY. This is another one of those moments where you must be completely honest with yourself for the sake of your film. Spend some serious time there and listen for things like trains and planes. Planes were the biggest problem for me when I shot Mnemosyne in the summer of 2003.

When you have your locations sussed, it might be a good idea to contact the council to see if they plan to do any roadworks/construction during your shooting schedule. For Mnemosyne, we used the very centre of Letchworth town for a scene. I got some of it shot. I then planned to shoot the next bit the weekend after. Big mistake! The council ripped up the road where we shot - there was rubble and machinery everywhere. Even if they don't rip up roads, etc, they might still cause noise pollution close to your film, so it's worth checking.

The shooting schedule is more tricky, because sometimes the people working on your film might have 9-5 jobs and only be available on weekends. In my experience, it is better to just shoot the thing in a block of days, because if you dot the production about over weekends it will lose impetus. If your script is that good, people will take some days holiday off their jobs to work on the film. You could always shoot on the weekend and then part of the week. It all depends on how much there is to shoot, and how much coverage you want to get. Then, of course, there is the darned weather!!!

When you have a shooting schedule together, it is inevitable that it will not stay on course if you have never worked with a crew before. I learned the hard way (angry actors due to trial-and-error scheduling), but by the end of the shoot, we were pretty much minute-for-minute in sync with the schedule. Some tips I would give for the pre-production phase are:

• Make the first shot that you film a simple one. The first shot always seems to take the longest so don't make it complicated. This is because you and your crew will be working together for the first time, and it takes time for a team to gel and become used to each other.
• Start as early as possible. You may think you are being Mr Nice Guy by letting everyone have a lay-in, but this can only lead to overruns, and an angry crew. They are professionals so if you ask them to turn up at 8am, they will!
• Block off each day's shoot into a series of camera-setups, and associated shot numbers.
• Give yourself triple the time you think you will need for each camera set-up.
• Schedule in sizeable breaks.
• Storyboard the film by photographing each shot, then drawing the characters in using a paint-package. I did this (have a look) and it was extremely helpful to the cameraman and DoP (Director of Photography). Not only that, but it allows everyone to virtually see the film before you even begin shooting it.

Once you have a storyboard, a complete shot list, a shooting schedule, and good, reliable locations, you are ready to cast and crew your film. When you post your advert, state the name of your production company (You don't actually have to own a company - but it is more professional to have a 'name' which you operate under), a contact name and number, a location, an overview of the schedule, whether it is paid work or not (in most cases not), what the actors can expect (profit share, copy of film, reimbursement for travel+food, etc), and a desription of the characters (gender, height, age, traits, personality, etc). You will then receive a few mails back from actors who think they fit one of the listed characters. They may enclose a CV, or a link to a web-enabled CV, normally with a photo. If you think they sound right, send them the script. If they like it, they'll write back and put themselves forward for casting.

I arranged two casting days using a friend's flat in London, and my own flat in Letchworth. Always try and make it somewhere where the actors can get to quite easily and without too much expense, as producers never fund travel to auditions (otherwise we'd all be broke). I never actually interviewed my crew in person. I spoke to them all on the phone (one person I hired just from e-mail conversations). For casting I provided a web page with details of how to get to the casting. Here is the actual casting web page I made.

I have provided a few 'best practices' when it comes to casting. They are:

• Send the script ahead of time
• Give thorough and helpful directions to the auditions
• Provide as many contact details as you can
• Consider allowing the actors to choose a reading segment from the film that they feel will help them perform best
• Have refreshments on hand (tea, coffee, etc)
• Give actors an opportunity to bring showreels, etc
• Ensure actors are relaxed and comfortable
• Ask their permission to film them during the audition
• If you have permission, do an IDENT (They introduce themselves plus their character)
• Be honest about the limitations of the project
• Ask them about their thoughts on the character they will play
• Explain why the project might benefit them
• Check actors availability for when you plan to shoot
• Give them an opportunity to ask questions
• Remember actors don't like directors who are arrogant/condescending
• Let the actors know when they can expect to hear from you

Once you have made a decision, inform your first choices that they have been cast. Do not send out any rejection letters until you have had acceptance letters/e-mails from them. At this point, try and be as helpful as you can to the actors who did not get the parts. Actors appreciate honest responses about why they did not get the part. Some people do not even send rejection letters. That must be pretty awful, so if you can make the effort to tell them why, it will help them a lot. Also, if someone came in at second place for a role, make sure you tell them that and possibly enquire if they woul be interested in understudying the role (Sometimes people will drop out at the last minute for paid work). One other thing - I don't deal with agencies - I've never had a bad experience with one simply because I ignore their mails. It's up to you if you accept cast members from agencies, but remember it is another layer that could cause complications down the line.

The final thing I should mention on this pre-production section is insurance. It's up to you if you operate without insurance, and for a short film, sometimes not having insurance could be a risk worth taking. But for a feature film, ensure that you have got proper production insurance. This will cover you for accidents, equipments, etc.

Many people think that having an idea is all it takes to filmmaking. While most editing process can be done digitally, the basic filmmaking process applies across the globe. You don’t usually step into scene and start filming aimlessly. Scripts need to be written, storyboards sketched and visual directions confirmed. A big idea is just the starting point of creating a film.

Here are the five basic steps to creating a film.

1. The Script
Whether the film is a silent one with no dialogue or one filled with conversations, producing it need to start with a script. Although most directors leave room for actors to improvise, a script acts as a guideline for actors to understand characters and plots. Some directors, like Wong Kar-wai (In the Mood for Love) is prone to changing his script and prefers his cast to create dialogues as they go along, but a script is necessary, nonetheless, and it can take years to develop.

2. Crew & Cast
Usually, a screenwriter’s job is done after the script is written. Once it is submitted to the producer, the script is officially out of the writer’s hands. The producer then makes changes according to his or her preference, and chooses the director and crews to work on the project before holding an audition to select the cast. However, not all actors need to be auditioned and not all directors will cast their actors through an audition.

3. Cameras & Storyboards
Besides the story script, another set of script is needed before filming could take place. It’s known as Shooting Script which includes scene breakdowns and technical notes such as camera angles, lighting, prop placement, audio notes and location lists. The film director will then develop storyboards – equivalent to a comic book for the film – which shows how the film will look like visually.

4. Production
With the script and storyboards in hand and a good cast, you’re ready to create and start shooting the film. This process can take months though ironically, it’s only two hours onscreen. The cast and crew can spend more than twelve hours on the set just to film a four-page script. Bear in mind that filming costs a lot. It’s important to identify your budget and work with it.

5. Post-production
This is the most important stage as it creates the rhythm of the final film. There are three things involved in the post-production process: film editing and correction, re-shoots and marketing. As sound is recorded separately during filming, it needs to be synched up at this stage at the post-production office. Sometimes, certain scenes require re-shooting sessions if the story doesn’t seem to blend properly after editing. While the film editor and director edits the unnecessary footages and puts the story together, the marketing team goes out to negotiate distribution deals and work out strategies to promote the film.

So there you go – five simple steps to producing your first short film. Filmmaking is essentially an art that demands lots of talent and hard work. Award-winning films are made with lots of money and a large, knowledgeable crew. But ultimately, regardless of how well-made a film is, it will be useless if one is not savvy about marketing and gaining an audience. It is after all, a business.

If you are inspired to be a filmmaker or be part of the filmmaking process, you should stop talking about it and get involved. The best way is to work in a real production as a crew or production assistant because that will provide you with the right training and exposure. Or if you are looking at making short films for fun, you could always pick up the digital video camera. In today’s digital era, it is relatively easy to produce one. Get creative!

Mini Bites of the day: If you have dreams, you have to go the mile to make them come true because no one else could turn it into reality but you.

The number one rule of filmmaking (and life) is to be nice. I had to mention this a few times today with my girls. We were in a rather toasty room and the heat and the close quarters were wearing them a little thin. One said something that hurt the other's feelings and it spiraled downhill from there. These girls are rock stars and it's so hard to make them believe it. They doubt themselves way more than I expected. And I know it's just the age, but it really bums me out. I just wish they could see themselves in ten years. See themselves a little more comfortable in their skins, a little more confident with their talents and a little more aware that not everyone's opinions really matter but their own.

But I digress. Back to the number one rule. Filmmaking is a collaborative effort. Many, many names appear at the end of a movie and all of those names, from craft services to executive producer, have made their mark on that screen. The best filmmaking experiences are those you share with people who feel like family, or rather become your family ... on set, in the editing room, when you book theaters in far away places. It's a shared experience and definitely for me, one of the coolest.

So people, take it to heart. The world would be so much more awesome if everyone was nice. Sigh.

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. Several mainstream Hollywood movies have now been shot digitally, and many vendors have brought products to market, including traditional film camera vendors like Arri and Panavision, 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 hotly debated, but digital cinematography cameras sales have surpassed mechanical cameras in the classic 35mm format.
Technology
Digital cinematography captures motion pictures digitally, in a process analogous to digital photography. While there is no clear technical distinction that separates the images captured in digital cinematography from video, the term "digital cinematography" is usually applied only in cases where digital acquisition is substituted for film acquisition, such as when shooting a feature film. The term is not generally applied when digital acquisition is substituted for analog video acquisition, as with live broadcast television programs.
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 35mm film frame or even (as with the Vision 65) a 65mm 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 65mm motion picture film cameras, which is important because many cinematographers consider selective focus an essential visual tool.
Prosumer and broadcast television cameras typically use three 1/3" or 2/3" sensors in conjunction with a prism, with each sensor capturing a different color. Camera vendors like Sony and Panasonic, which have their roots in the broadcast and consumer camera markets, have leveraged their experience with these designs into three-chip products targeted specifically at the digital cinematography market. The Thomson Viper also uses a three-chip design. These designs offer benefits in terms of color reproduction, but are incompatible with traditional cinematography lenses (though new lines of high-end lenses have been developed with these cameras in mind), and incapable of achieving 35mm depth of field unless used with depth-of-field adaptors, which can lower image sharpness and result in a loss of light.
CMOS Sensor
Complementary metal–oxide–semiconductor (CMOS), is a major class of integrated circuits. CMOS technology is used in microprocessors, microcontrollers, static RAM, and other digital logic circuits. CMOS technology is also used for a wide variety of analog circuits such as image sensors, data converters, and highly integrated transceivers for many types of communication. Frank Wanlass got a patent on CMOS in 1967 (US Patent 3,356,858).
CMOS is also sometimes referred to as complementary-symmetry metal–oxide–semiconductor. The words "complementary-symmetry" refer to the fact that the typical digital design style with CMOS uses complementary and symmetrical pairs of p-type and n-type metal oxide semiconductor field effect transistors (MOSFETs) for logic functions.
Two important characteristics of CMOS devices are high noise immunity and low static power consumption. Significant power is only drawn when the transistors in the CMOS device are switching between on and off states. Consequently, CMOS devices do not produce as much waste heat as other forms of logic, for example transistor-transistor logic (TTL) or NMOS logic, which uses all n-channel devices without p-channel devices. CMOS also allows a high density of logic functions on a chip.
The phrase "metal–oxide–semiconductor" is a reference to the physical structure of certain field-effect transistors, having a metal gate electrode placed on top of an oxide insulator, which in turn is on top of a semiconductor material. Instead of metal (usually aluminum in the very old days), current gate electrodes (including those up to the 65 nanometer technology node) are almost always made from a different material, polysilicon, but the terms MOS and CMOS nevertheless continue to be used for the modern descendants of the original process. Metal gates have made a comeback with the advent of high-k dielectric materials in the CMOS process, as announced by IBM and Intel for the 45 nanometer node and beyond.
CCD Sensor or Charge-coupled device
A charge-coupled device (CCD) is an analog shift register, enabling analog signals (electric charges) to be transported through successive stages (capacitors) controlled by a clock signal. Charge coupled devices can be used as a form of memory or for delaying analog, sampled signals. Today, they are most widely used for serializing parallel analog signals, namely in arrays of photoelectric light sensors. This use is so predominant that in common parlance, "CCD" is (erroneously) used as a synonym for a type of image sensor even though, strictly speaking, "CCD" refers solely to the way that the image signal is read out from the chip.
The capacitor perspective is reflective of the history of the development of the CCD and also is indicative of its general mode of operation, with respect to readout, but attempts aimed at optimization of present CCD designs and structures tend towards consideration of the photodiode as the fundamental collecting unit of the CCD. Under the control of an external circuit, each capacitor can transfer its electric charge to one or other of its neighbors. CCDs are used in digital photography and astronomy (particularly in photometry), sensors, electron microscopy, medical fluoroscopy, optical and UV spectroscopy and high speed techniques such as lucky imaging.
Acquisition Formats
While many people make movies with MiniDV camcorders and other consumer and prosumer products that have lower resolutions or shoot interlaced video, cameras marketed as digital cinematography cameras typically shoot in progressive HDTV formats such as 720p and 1080p, or in higher-end formats created specifically for the digital cinematography market, such as 2K and 4K.
To date, 1080p has been the most common format for digitally acquired major motion pictures. In the summer of 2007, director Steven Soderbergh began shooting "The Argentine" and "Guerrilla", due for release in 2008, with prototype Red One 4K camera, making these the first two major motion pictures shot in the 4K format.
Data Storage
Tape vs. Data-Centric
Broadly, there are two paradigms used for data storage in the digital cinematography world.
Many people, particularly those coming from a background in broadcast television, are most comfortable with video tape based workflows. Data is captured to video tape on set. This data is then ingested into a computer running non-linear editing software, using a deck. Once on the computer, the footage is edited, and then output in its final format, possibly to a film recorder for theatrical exhibition, or back to video tape for broadcast use. Original video tapes are kept as an archival medium. The files generated by the non-linear editing application contain the information necessary to retrieve footage from the proper tapes, should the footage stored on the computer's hard disk be lost.
Increasingly, however, digital cinematography is shifting toward "tapeless" workflow, where instead of thinking about digital images as something that exists on a physical medium like video tape, digital video is conceived of as data in files. In tapeless workflow, digital images are usually recorded directly to files on hard disk or flash memory based "digital magazines". At the end of a shooting day (or sometimes even during the day), the digital files contained on these digital magazines are downloaded, typically to a large RAID connected to an editing system. Once data is copied from the digital magazines, they are erased and returned to the set for more shooting. Archiving is accomplished by backing up the digital files from the RAID, using standard practices and equipment for data backup from the Information Technology industry, often to data tape.
Compression
Digital cinema cameras are capable of generating extremely large amounts of data; often hundreds of megabytes per second.To help manage this huge data flow, many cameras or recording devices designed to be used in conjunction with them offer compression. Prosumer cameras typically use high compression ratios in conjunction with chroma subsampling. While this allows footage to be comfortably handled even on fairly modest personal computers, the convenience comes at the expense of image quality.
High-end digital cinematography cameras or recording devices typically support recording at much lower compression ratios, or in uncompressed formats. Additionally, digital cinematography camera vendors are not constrained by the standards of the consumer or broadcast video industries, and often develop proprietary compression technologies that are optimized for use with their specific sensor designs or recording technologies.
Lossless vs. lossy compression
A lossless compression system is capable of reducing the size of digital data in a fully reversible way -- that is, in a way that allows the original data to be completely restored, byte for byte. This is done by removing redundant information from a signal. Digital cinema cameras rarely use only lossless compression methods, because much higher compression ratios (lower data rates) can be achieved with lossy compression. With a lossy compression scheme, information is discarded to create a simpler signal. Due to limitations in human visual perception, it is possible to design algorithms which do this with little visual impact.
Chroma subsampling
Chroma subsampling is the practice of encoding images by implementing more resolution for luma information than for chroma information. It is used in many video encoding schemes—both analog and digital—and also in JPEG encoding.
Rationale
Because of storage and transmission limitations, there is always a desire to reduce (or compress) the signal. Since the human visual system is much more sensitive to variations in brightness than color, a video system can be optimized by devoting more bandwidth to the luma component (usually denoted Y'), than to the color difference components Cb and Cr. The 4:2:2 Y'CbCr scheme for example requires two-thirds the bandwidth of (4:4:4) R'G'B'. This reduction results in almost no visual difference as perceived by the viewer.
How subsampling works
Because the human visual system is less sensitive to the position and motion of color than luminance, bandwidth can be optimized by storing more luminance detail than color detail. At normal viewing distances, there is no perceptible loss incurred by sampling the color detail at a lower rate. In video systems, this is achieved through the use of color difference components. The signal is divided into a luma (Y') component and two color difference components (chroma).
Chroma subsampling deviates from color science in that the luma and chroma components are formed as a weighted sum of gamma-corrected (tristimulus) R'G'B' components instead of linear (tristimulus) RGB components. As a result, luminance and color detail are not completely independent of one another. There is some "bleeding" of luminance and color information between the luma and chroma components. The error is greatest for highly-saturated colors and can be somewhat noticeable in between the magenta and green bars of a color bars test pattern (that has chroma subsampling applied). This engineering approximation (by reversing the order of operations between gamma correction and forming the weighted sum) allows color subsampling to be more easily implemented.
Bitrate
Video and audio compression systems are often characterized by their bitrates. Bitrate describes how much data is required to represent one second of media. One cannot directly use bitrate as a measure of quality, because different compression algorithms perform differently. A more advanced compression algorithm at a lower bitrate may deliver the same quality as a less advanced algorithm at a higher bitrate.
Intra- vs. Inter-frame compression
Most compression systems used for acquisition in the digital cinematography world compress footage one frame at a time, as if a video stream is a series of still images. Inter-frame compression systems can further compress data by examining and eliminating redundancy between frames. This leads to higher compression ratios, but displaying a single frame will usually require the playback system to decompress a number of frames that precede it. In normal playback this is not a problem, as each successive frame is played in order, so the preceding frames have already been decompressed. In editing, however, it is common to jump around to specific frames and to play footage backwards or at different speeds. Because of the need to decompress extra frames in these situations, inter-frame compression can cause performance problems for editing systems. Inter-frame compression is also disadvantageous because the loss of a single frame (say, due to a flaw writing data to a tape) will typically ruin all the frames until the next keyframe occurs. In the case of the HDV format, for instance, this may result in as many as 6 frames being lost with 720p recording, or 15 with 1080i recording
Digital vs. film cinematography
Technical Considerations
Predictability
When shooting on film, response to light is determined by what film stock is chosen. A cinematographer can choose a film stock he or she is familiar with, and expose film on set with a high degree of confidence about how it will turn out. Because the film stock is the main determining factor, results will be substantially similar regardless of what camera model is being used. However, the final result cannot be controlled when shooting with mechanical cameras until the film negative has been processed at a laboratory. Therefore, damage to the film negative, scratches which are generated by faulty camera mechanics etc can not be controlled.
In contrast, when shooting digitally, response to light is determined by the CMOS or CCD sensor(s) in the camera and recorded and "developed" directly. This means a cinematographer can measure and predict exactly how the final image will look by eye if familiar with the specific model of camera being used or able to read a vector/waveform.
On-set monitoring allows the cinematographer to see the actual images that are captured, immediately on the set, which is impossible with film. With a properly calibrated high-definition display, on-set monitoring, in conjunction with data displays such as histograms, waveforms, RGB parades, and various types of focus assist, can give the cinematographer a far more accurate picture of what is being captured than is possible with film. However, all of this equipment may impose costs in terms of time and money, and may not be possible to utilize in difficult shooting situations.
Film cameras do often have a video assist that captures video though the camera to allow for on-set playback, but its usefulness is largely restricted to judging action and framing. Because this video is not derived from the image that is actually captured to film, it is not very useful for judging lighting, and because it is typically only NTSC-resolution, it is often useless for judging focus.
Portability
Ultra-lightweight and extremely compact digital cinematography cameras, as the SI:2K mini, are much smaller and lighter than mechanical film cameras. Other High-end digital cinema cameras can be quite large, and some models require bulky external recording mechanisms (though in some cases only a small strand of optical fiber is necessary to connect the camera and the recording mechanism).
Compact 35mm film cameras that produce the full 35mm film resolution and accept standard 35mm lenses cannot be sized down below a certain size and weight, as they require at least space for the film negative and basic mechanics.
Smaller form-factor digital cinema cameras such as the Red One and SI-2K have made digital more competitive in this respect. The SI-2K, in particular, with its detachable camera head, allows for high-quality images to be captured by a camera/lens package that is far smaller than is practically achievable with a 35mm film camera and is used in many scenarios to replace film - especially for stereoscopic productions.
Dynamic Range
The sensors in most high-end digital video cameras have less exposure latitude (dynamic range) than modern motion picture film stocks. In particular, they tend to 'blow out' highlights, losing detail in very bright parts of the image. If highlight detail is lost, it is impossible to recapture in post-production. Cinematographers can learn how to adjust for this type of response using techniques similar to those used when shooting on reversal film, which has a similar lack of latitude in the highlights. They can also use on-set monitoring and image analysis to ensure proper exposure. In some cases it may be necessary to 'flatten' a shot, or reduce the total contrast that appears in the shot, which may require more lighting to be used.
Many people also believe that highlights are less visually pleasing with digital acquisition, because digital sensors tend to 'clip' them very sharply, whereas film produces a 'softer' roll-off effect with over-bright regions of the image. Some more recent digital cinema cameras attempt to more closely emulate the way film handles highlights, though how well they achieve this is a matter of some dispute. A few cinematographers have started deliberately using the 'harsh' look of digital highlights for aesthetic purposes. One notable example of such use is Battlestar Galactica.
Digital acquisition typically offers better performance than film in low-light conditions, allowing less lighting and in some cases completely natural or practical lighting to be used for shooting, even indoors. This low-light sensitivity also tends to bring out shadow detail. Some directors have tried a "best for the job" approach, using digital acquisition for indoor or night shoots, and traditional film for daylight exteriors.
Resolution
Substantive debate over the subject of film resolution vs. digital image resolution is clouded by the fact that it is difficult to meaningfully and objectively determine the resolution of either.
Unlike a digital sensor, a film frame does not have a regular grid of discrete pixels. Rather, it has an irregular pattern of differently sized grains. As a film frame is scanned at higher and higher resolutions, image detail is increasingly masked by grain, but it is difficult to determine at what point there is no more useful detail to extract. Moreover, different film stocks have widely varying ability to resolve detail.
Determining resolution in digital acquisition seems straightforward, but is significantly complicated by the way digital camera sensors work in the real world. This is particularly true in the case of high-end digital cinematography cameras that use a single large bayer pattern CMOS sensor. A bayer pattern sensor does not sample full RGB data at every point; each pixel is biased toward red, green or blue, and a full color image is assembled from this checkerboard of color by processing the image through a demosaicing algorithm. Generally with a bayer pattern sensor, actual resolution will fall somewhere between the "native" value and half this figure, with different demosaicing algorithms producing different results. Additionally, most digital cameras (both bayer and three-chip designs) employ optical low-pass filters to avoid aliasing. Such filters reduce resolution.
In general, it is widely accepted that film exceeds the resolution of HDTV formats and the 2K digital cinema format, but there is still significant debate about whether 4K digital acquisition can match the results achieved by scanning 35mm film at 4K, as well as whether 4K scanning actually extracts all the useful detail from 35mm film in the first place. However, as of 2007 the majority of films that use a digital intermediate are done at 2K because of the costs associated with working at higher resolutions. Additionally, 2K projection is chosen for almost all permanent digital cinema installations, often even when 4K projection is available.
One important thing to note is that the process of optical duplication, used to produce theatrical release prints for movies that originate both on film and digitally, causes significant loss of resolution. If a 35mm negative does capture more detail than 4K digital acquisition, ironically this may only be visible when a 35mm movie is scanned and projected on a 4K digital projector.
Grain & Noise
Film has a characteristic grain structure, which many people view positively, either for aesthetic reasons or because it has become associated with the look of 'real' movies. Different film stocks have different grain, and cinematographers may use this for artistic effect.
Digitally acquired footage lacks this grain structure. Electronic noise is sometimes visible in digitally acquired footage, particularly in dark areas of an image or when footage was shot in low lighting conditions and gain was used. Some people believe such noise is a workable aesthetic substitute for film grain, while others believe it has a harsher look that detracts from the image.
Well shot, well lit images from high-end digital cinematography cameras can look almost eerily clean. Some people believe this makes them look "plasticky" or computer generated, while others find it to be an interesting new look, and argue that film grain can be emulated in post-production if desired.
Since most theatrical exhibition still occurs via film prints, the super-clean look of digital acquisition is often lost before moviegoers get to see it, because of the grain in the film stock of the release print.
Digital Intermediate Workflow
The process of using digital intermediate workflow, where movies are color graded digitally instead of via traditional photochemical finishing techniques, has become common, largely because of the greater artistic control it provides to filmmakers. In 2007, all of the 10 most successful movies released used the digital intermediate process.
In order to utilize digital intermediate workflow with film, the camera negative must be processed and then scanned. High quality film scanning is time consuming and expensive. With digital acquisition, this step can be skipped, and footage can go directly into a digital intermediate pipeline as digital data.
Some filmmakers have years of experience achieving their artistic vision using the techniques available in a traditional photochemical workflow, and prefer that finishing process. While it would be theoretically possible to use such a process with digital acquisition by creating a film negative on a film recorder, in general digital acquisition is not a suitable choice if a traditional finishing process is desired.
Sound
Films are traditionally shot with dual-system recording, where picture is recorded on camera, and sync sound is recorded to a separate sound recording device. In post-production, picture and sound are synced up.
Many cameras used for digital cinematography can record sound internally, already in sync with picture. This eliminates the need for syncing in post, which can lead to faster workflows. However, most sound recording is done by specialist operators, and the sound will likely be separated and further processed in post-production anyway. Also, recording sound to the camera may require running additional cables to the camera, which may be problematic in some shooting situations, particularly in shots where the camera is moving. Wireless transmission systems can eliminate this problem, but are not suitable for use in all circumstances.
Archiving
Many people feel there is significant value in having a film negative master for archival purposes. As long as the negative does not physically degrade, it will be possible to recover the image from it in the future, regardless of changes in technology. In contrast, even if digital data is stored on a medium that will preserve its integrity, changes in technology may render the format unreadable or expensive to recover over time. For this reason, film studios distributing digitally-originated films often make film-based separation masters of them for archival purposes.
Economics
Low-budget / Independent Filmmaking
For the last 25 years, many respected filmmakers like George Lucas have predicted that electronic or digital cinematography would bring about a revolution in filmmaking, by dramatically lowering costs.
For low-budget and so-called "no-budget" productions, digital cinematography on prosumer cameras clearly has cost benefits over shooting on 35mm or even 16mm film. The cost of film stock, processing, telecine, negative cutting, and titling for a feature film can run to tens of thousands of dollars according to From Reel to Deal, a book on independent feature film production by Dov S-S Simens. Costs directly attributable to shooting a low-budget feature on 35mm film could be $50,000 on the low side, and over twice that on the high side. In contrast, obtaining a high-definition prosumer camera and sufficient tape stock to shoot a feature can easily be done for under $10,000, or significantly less if, as is typically the case with 35mm shoots, the camera is rented.
If a 35mm print of the film is required, an April 2003 article in American Cinematographer found the costs between shooting film and video are roughly the same. The benefit to shooting video is that the cost of a film-out is only necessary should the film find a distributor to pick up the cost. When shooting film, the costs are upfront and cannot be deferred in such a manner. On the other hand, the same article found 16mm film to deliver better image quality in terms of resolution and dynamic range. Given the progress digital acquisition, film recording, and related technologies have seen in the last few years, it is unclear how relevant this article is today.
Most extremely low-budget movies never receive wide distribution, so the impact of low-budget video acquisition on the industry remains to be seen. It is possible that as a result of new distribution methods and the long tail effects they may bring into play, more such productions may find profitable distribution in the future. Traditional distributors may also begin to acquire more low-budget movies as better affordable digital acquisition eliminates the liability of low picture quality, and as they look for a means to escape the increasingly drastic "boom and bust" financial situation created by spending huge amounts of money on a relatively small number of very large movies, not all of which succeed.
Hollywood
On higher budget productions, the cost advantages of digital cinematography are not as significant, primarily because the costs imposed by working with film are simply not major expenses for such productions. Two recent films, Sin City and Superman Returns, both shot on digital tape, had budgets of $40 million and close to $200 million respectively. The cost savings, though probably in the range of several hundred thousand to over a million dollars, were negligible as a percentage of the total production budgets in these cases.
Rick McCallum, a producer on 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. However, this does not necessarily indicate the actual cost savings. The low incremental cost of shooting additional footage may encourage filmmakers to use far higher shooting ratios with digital. The lower shooting ratios typical with film may save time in editing, lowering post-production costs somewhat.
Shooting in digital requires a digital intermediate workflow, which is more expensive than a photochemical finish. However, a digital intermediate may be desirable even with film acquisition because of the creative possibilities it provides, or a film may have a large number of effects shots which would require digital processing anyway. Digital intermediate workflow is coming down in price, and is quickly becoming standard procedure for high-budget Hollywood movies.
Digital cinematography cameras
Professional cameras include the Sony HDCAM Series, RED One, Panavisions Genesis, SI-2K, Thomson Viper, Vision Research Phantom, Weisscam, GS Vitec noX, and the Fusion Camera System. Independent filmmakers have also pressed low-cost consumer and prosumer cameras into service for digital filmmaking.
Industry acceptance of digital cinematography
For over a century, virtually all movies have been shot on film and nearly every film student learns about how to handle 16mm and 35mm film.
Today, digital acquisition accounts for the vast majority of moving image acquisition, as most content for broadcast is shot on digital formats. Most movies destined for theatrical release are still shot on film, however, as are many dramatic TV series and some high-budget commercials. High-end digital cinematography cameras suitable for acquiring footage intended for theatrical release are on the market since 1999/2000, and have meanwhile gained widespread adoption.