DVA101 DV Camcorder Fundamentals

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Digital Video Camcorder Fundamentals:

Digital Video Camcorder Fundamentals

What Are These?:

What Are These?

They’re All Digital Video Camcorders:

They’re All Digital Video Camcorders All of these devices have: A viewfinder or display A lens An imaging system to convert the incoming light from the lens into an electronic signal Media to record that signal as digital information – a series of 1’s and 0’s A means to share that digital information with others

Camera Phone / Web Video Camera:

Camera Phone / Web Video Camera The “Swiss Army Knife” of digital content creation Records picture and sound as compressed MPEG-4 files to solid state memory Pros Pocket-sized Easy to use Videos can be emailed or uploaded directly to the web Cons Small lens Very small size leads to very shaky handling Difficult to fine-tune Poor audio quality MPEG-4 compression results in picture quality that is below broadcast standard

The Handycam:

The Handycam Available in a variety of prices from the $100’s to the low $1,000’s Record to tape, DVD, solid state media or hard drives Pros Small, lightweight Ideal for family videos Make images that are good enough quality for TV viewing – some now in HD Cons Small size leads to shakiness Lenses and imagers, while better than camera phones, are still below broadcast standards Images are still compressed Lack professional features

The “Pro-Sumer”:

The “Pro-Sumer” The choice for indie filmmakers, event videographers, and some television producers Range from $4,000 or so up into the $20,000’s Record to tape, hard drives, or high capacity solid state media Pros Superior quality lenses and imagers Some professional features and better controls Larger size and shoulder mounting equal more stability Easy postproduction workflow

The Professional:

The Professional Prices in the $40,000 to $300,000 range Record to tape, hard drives, or high capacity solid state media Pros An incredible array of best-quality lenses and accessories Higher resolution imagers make extremely crisp pictures Designed by professional cinematographers for the rigors of film and TV production Cons Extremely expensive Postproduction workflow is more complicated

Pro-Sumer Gear FTW!:

Pro-Sumer Gear FTW! The “Pro-Sumer” class of camcorders provides the best combination of features, workflow, image quality, and affordability Technique is the same as on the professional models The Canon XL1/XL2 series was the “gold standard” of Pro-Sumer camcorders for many years Standard Definition MiniDV format

Standard vs. High Definition:

Standard vs. High Definition While the world is rapidly moving to all High Definition (HD) production, we work in Standard Definition (SD) in DVA101 Easier production and postproduction workflow Cameras are less expensive Techniques are the same regardless of resolution A note on resolutions HD = 1920x1080 or 1280x720 SD = 720x480 MPEG-4 cameras = 640x480 or even lower!

What is “MiniDV?”:

What is “MiniDV?” “DV” is an international standard created by a consortium of 10 companies for a consumer digital video format. Panasonic, Sony, JVC, Philips, N.V., Sanyo, Hitachi, Sharp, Thomson Multimedia, Mitsubishi Electric, and Toshiba There are now over 60 companies in the DV consortium. “MiniDV” is the name of the small-sized DV tapes used in cameras such as the XL1 Rule of thumb: 5 minutes of DV = 1 gigabyte of data! Left to right: DVCAM-L, DVCPRO-M, MiniDV

Digital vs. Analog :

Digital vs. Analog Analog video formats record picture and sound information as electronic voltages Just like audiocassettes – prone to noise and degradation Copying of these signals would further degrade quality Digital video formats record picture and sound information as bits – ONES and ZEROS Like CD’s – discrete packets of data more faithful to the original information Allows for better-quality originals and copies Enables a seamless computer-based postproduction workflow

Relative Quality of Various Formats:

Relative Quality of Various Formats Digital Digital Betacam, Ampex DCT 9.7 DV, DVCAM, D-7 (DVCPRO) 9 Analog MII, Betacam SP 8.9 Video 8, Betamax 4 VHS 3 (on a scale of 1-10, 10 being the best quality possible)

Camcorder Components:

Camcorder Components It’s best to think of a camcorder as 2 different pieces of equipment CAM(era re)CORDER In fact, the earliest portable video camera setups were 2 separate pieces, a handheld camera tethered to a VCR carried in a backpack or shoulder bag.

The Camera:

The Camera Optics Zoom lens Iris Imager(s) Shutter Stabilizer Gain Circuit White Balance

Optics: The Zoom Lens:

Optics: The Zoom Lens As you rotate the zoom ring or activate the zoom rocker on a lens system, you are moving a set of optics inside the lens housing The position of the internal optics can zoom out to see a wider view (top diagram) or zoom in to see a closer (telephoto) view (bottom diagram) This is called an “optical” zoom

Optical vs. Digital Zoom:

Optical vs. Digital Zoom Most consumer camcorders come with a “digital zoom” feature that extends the zoom range of the lens A digital zoom electronically zooms into the image and degrades the picture (as in this example); therefore digital zooms should be avoided!

Optics: The Iris:

Optics: The Iris The iris is a circular array of blades at the back of the lens Can be dialed open or closed, allowing more or less light into the imager This is the principle way to adjust the exposure (brightness level) of your image At first we will work with camera’s iris set to Auto, but true control comes when you master Manual Exposure settings

Imagers (a.k.a. “Chips”):

Imagers (a.k.a. “Chips”) CCD (Charge-Coupled Device) or CMOS (Complementary Metal-Oxide Semiconductor) These solid-state electronic components have been micro-manufactured and segmented into an array of individual light-sensitive cells called "photosites.” Each photosite is one element of the whole picture that is formed, called a picture element, or "pixel.“ Chips found in camcorders have a pixel array that is a few hundred photosites high by a few hundred photosites wide.

Camera Varieties:

Camera Varieties Single-chip Lower-end consumer cameras only have one chip. Oddly, some very high end pro cameras only have one chip! (Usually a CMOS imager.) One chip gathers all colors. Three-chip Each chip gathers just one color - red, green or blue Our XL2’s have 3 CCD’s

Shutter:

Shutter Determines how long each frame of video is “exposed” Think of it as the camera’s “refresh rate” Based on the shutter in motion picture cameras A rotating semi-circle which periodically “blanks” the imaging area, allowing the film to advance to the next frame without light smear.

Shutter Speed:

Shutter Speed “Normal” speed is 1/60 th of a second Corresponds to the rate of image creation (30fps x 2 fields per frame) “Slow” speeds (1/30 th , 1/15 th , etc.) Longer exposures More light entering imagers More motion blur “Fast” speeds (1/100 th , 1/1000 th , etc.) Shorter exposures Less light entering imagers Less motion blur An example of an extremely slow shutter speed with exaggerated motion blur

Image Stabilizers:

Image Stabilizers All modern consumer camcorders include some form of image stabilization (IS) Digital Zooms into image a little (reducing resolution) Optical Uses a mechanism inside the lens housing to counteract movement of camera Better quality – does not degrade image Top: without Image Stabilization; Bottom: with IS

The Recorder:

The Recorder Stores signals camera onto tape, solid state media, or hard drive Video Images produced by the imager(s) are processed and compressed as data Audio From on-board microphone High-end cameras allow for connection of external sources Timecode Provides a discrete address for every image on the tape in hours, minutes, seconds, frames (hh;mm;ss;ff) Makes editing MUCH easier

Getting It Out:

Getting It Out All camcorders include some capability to share the images they produce MPEG-4 camcorders can connect to a computer via USB and the video files can be copied MiniDV camcorders include FireWire (top), a connection protocol built specifically for moving digital video between devices High-end HD cameras include a digital protocol called HD-SDI (Serial Digital Interface) All cameras include some sort of audio-video connections (bottom)

Safety & Good Practice:

Safety & Good Practice Make sure camera works and has all accessories BEFORE you leave for a shoot! Don’t get your camera wet Beware of magnetized areas Strong magnetic fields can distort picture quality DO NOT point the camera or viewfinder at the sun Damages camera and your eye Keep dust and sand out of the camera

Cleaning:

Cleaning Clean lenses rarely and with great care Use good lens tissue or lens cloth Avoid getting the lens dirty Avoid getting the viewfinder or camera body dirty Wipe with a clean cloth – do not use water or cleaning agents!

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