Before You Start Using the RED One

(1)   RED Camera Manual User Help Guide  >  Before You Start Using the RED One

This area is short in the manual, but it touches on some key concepts that are worth exploring a little more deeply.

The PL Mount.

The RED ONE camera ships with a PL mount. To protect against dust or other contaminants entering the optical path, ensure the lens cap is used at all times a lens is not mounted to the camera. Additional lens mounts and adaptors are available for use with non-PL mount lenses.

This simply refers to the type of fitting on the front of the camera that will accept lenses. The important thing to know here is that you must use lenses with a PL Mount. There are other standards, and there are adapters that you can get to modify your One to accept the other standards. I'm not going to discuss Lenses here - but it is worth noting that the PL Mount is the standard for much of the Film industry and you should not have trouble finding nice 35mm lenses for use on your One.

12 Bit Digital Images

In addition to capturing 12-bit resolution digital RAW images

The next big idea crammed into this paragraph is the "12-bit resolution digital RAW images." This term is important, and frankly, slightly mis-used here. The 12 bits refers to Color Depth, it is rarely called 12-bit resolution.

Let me rephrase their sentence: The One is capable of shooting up to 4k resolution at 12-bits of color.

Now for the explanation. When one is looking at a still frame of imagery - be it a digital photo or a single frame from moving footage - there are two basic attributes that every image will have:

1. Resolution - the size of the image. This can be measured in many different units like inches, mm, picas, points - but the unit of measure for digital imaging is always Pixels. A pixel represents one dot on your screen or in the image. HD television has a resolution of 1920 x 1080 pixels which is really close to what some would call 2K. This gets a little confused because when 2K was originally used - it refered to a 2K square image - like the frame on a film negative - which would be double the Horizontal lines of HD. Nowadays it is used to describe any aspect ratio that has approximately 2000 pixels across. 4K refers to 4000 horizontal pixels resolution. 4K resolution does a pretty good job of approximating the resolution 35mm film - although the emulsion on film is an analog process.
   
   Its important to note that when you double your resolution - you are quadrupling the amount of data. You can see this if you fold a piece of paper in half both vertically and horizontally - then open it up. The bottom left square is 2K, while the whole page represents 4K - twice the resolution. When you double the height you must double the width so when you double the resolution to 4K - you now have 4 times the area of the single square. Thus double the resolution = four times the data.
    
2. Color - this one gets a little more complicated. Lets start off with a the most simple of color spaces: 2 colors - Black and White. No Greys or other colors. A "bit" as used in the term "12 bit" is a switch - either on or off. Bits in a computer are represented with a 1 or 0. So our pixel that can be either Black or White would require 1 digital bit of color to store it in a computer or camera. If it is Black we store a Zero, if it is White we store a One. We can repeat this process for every pixel on the screen. Now we have an image - in black and white.
   
   Now lets add in some Greys. We'll limit the number of Greys to 256 shades between Black and White. Now we use our bits, and combine them to form a Byte. A Byte is 8 Bits. By combining the 1s and 0s in a byte we find that there are 2⁸ combinations of 1s and 0s and 2⁸ = 256. Now we can represent 256 shades of grey for each pixel on the screen. And to really get things going - lets push the number of bits to 12 - like the Red One™. With 12 bits we have access to 2¹² = 4096 shades of Grey for each pixel.
   
   What about Color though? There's a little curve ball here - each one of those pixels that we've been so conveniently thinking about as a single dot - is really made up of smaller components called color channels. There are a few basic color channels used often in the digital imaging world. The basic standard channels are Red, Green, and Blue (RGB); sometimes you will see component video cables with an additional channel for Black. So all we have to do to add color in to our previous discussion is to realize that each pixel really has at least 3 color values associated with it. Once the image is in the computer, there is also often a channel called an Alpha channel - this is used for special effects and compositing - it has no bearing on our discussion of the One.

So, what does 12 bits of color mean? It means that for every pixel being recorded - be it at HD or 4K - the RED One™ is capturing 12 bits of color information on the Red channel, the Green channel and the Blue channel. So in reality - the sensor is capable of registering 4096³ or 68,719,476,736 unique colors.

Its important to note that this is light and color data arriving to the sensor - it does not define accurately the final output of the Mysterium™ sensor or REDCODE codec. The sensor actually compressess some colors more than others.  We will talk about that later. It is also important to understand that the One uses a single Mysterium™ Sensor that captures all three channels of color on one chip. This is different from the cameras that use 3 separate CCDs.

Audio

the RED ONE camera supports four channels of 24-bit audio.

Now that we understand what bits are, we can apply this same concept to the audio. This simply tells us the range of sounds that the One can store in its chips. Again, and much like the visual side - ths does not tell us what frequency that information is being sampled. We will talk about this more later, but a quick example might help put this in context: while we know we can capture a nice range of sounds, if we only sample those sounds 1 time a minute it would not be a very effective recording media. The reality is that the RED One samples at 48 khz which means it is sampling 24 bits of audio data 48000 times a second. This is comparable to basic CDs, good recorders and samplers are capable of 96 and 128 bit depth audio - so if you really care about your audio - you should have a sound guy on-set recording audio seperately.

Frame Rate

The RAW images may be captured at a variety of frame rates, including single frame (still), timed interval (animation) and continuous image (video) modes.

The final component to moving pictures is moving pictures. In order to make them move, frames are flashed in front of the lens. The speed at which this happens is called the frame rate. Film uses 24 frames per second as the standard. This was arrived at mostly because of aesthtic decisions. If you wave your hand in front of you face, you will notice blur. The human eye is accustomed to this "motion blur." If you increase the frame rate, you get less blur because the shutter is spinning faster. This is very noticable when you compare the look of a soap opera - shot often on video where there is no shutter - the lcd was on or off - at 59.94 fps - to that of something shot on film. The other extreme is in the early days of film, when cameras were still cranked by hand, slower frame rates like 16 fps, 18fps, and 20fps were tried, and in the interim people have tried to "under-crank" the film to simply use less stock. After over 100 years of experimentation and no reason other than it "looks right" 24 fps is the standard for film.

What's important here is to remember that all those 1s and 0s need to be stored for every pixel of every frame of every second of footage. This is what's known as the DATA RATE. The data rate is the most basic number description of how much storage you will need. In the film world it would be like saying a 400' mag or 1000' mag instead of saying approximately 3 and a half minutes or 11 minutes. We'll get into a greater discussion of data rate when we talk about the codecs.

Summary of Chapter

Well, if you've made it this far I congratulate you. Just because this was the first chapter does not mean this stuff is easy. There's a lot of terminolgy crammed in to that first paragraph, and it makes a great scaffolding upon which we can further the discussion. You should now have a basic understanding of what lenses will fit your camera, 12 bit color depth at HD, 2K or 4K resolution, Data Rates, and a cursory introduction to digital audio.

Also check out:

The Official Wikipedia page for Digital Cinema