Technical Know How
Archive for July, 2010
Audio – Why is it so difficult to get it right?
Jul 21st
What is the reason, that the audio on our videos sounds often so much different as we have heard it during the recording of our footage? Without getting too technical, I would like to explain the principles of electronic sound recording. Once you understand how a microphone works, you can use it in ways to improve your audio track.
The two main characteristics, which determine the sound, is the polar pattern or directivity of the microphone and the sensitivity (volume), which is controlled by the electronic circuitry.
Capsule design and directivity
A microphone’s directionality or polar pattern indicates, how sensitive it is to sounds arriving at different angles about its central axis. Let’s have a look at a simple microphone device for converting sound into electrical energy. Its basic component is a diaphragm, that responds to the pressure or particle velocity of sound waves.
The inner elements of a microphone are the primary source of differences in directivity. A pressure microphone uses a diaphragm between a fixed internal volume of air and the environment, and responds uniformly to pressure from all directions, so it is said to be omnidirectional. A pressure-gradient microphone uses a diaphragm, that is at least partially open on both sides. The pressure difference between the two sides produces its directional characteristics. Other elements such as the external shape of the microphone and external devices such as interference tubes can also alter a microphone’s directional response. A pure pressure-gradient microphone is equally sensitive to sounds arriving from front or back, but insensitive to sounds arriving from the side, because sound arriving at the front and back at the same time creates no gradient between the two.
The characteristic directional pattern of a pure pressure-gradient microphone is like a figure-8. Other polar patterns are derived by creating a capsule, that combines these two effects in different ways. The cardioid, for instance, features a partially closed backside, so its response is a combination of pressure and pressure-gradient characteristics.
Polar patterns
An electronic circuitry controls the volume and sensitivity of the microphone and sound.
Below are some terminologies as used by professionals. Please keep in mind that any poor sound captured during production can be salvaged during post production.
AGC (Automatic Gain Control) is a circuit to automatically adjust a microphone’s gain (volume) to prevent too high levels, causing distortion or to raise sensitivity to hear quiet noises. It goes as far as an inbuilt camcorder microphone picks up the mechanical noises of a tape or disc drive. In this case it is a good idea to use an external microphone, which is positioned further away from the camera and closer to the action.
Below are some terminologies explained as they are used by professionals.
Audio Jargon
Ambient Sound
Background audio of a given environment. On-camera dialogue might be primary sound; traffic noise and refrigerator hum would be ambient.
Hiss:
Interference in audio recording, result of circuit noise from a playback recorder’s amplifiers or from a tape’s residual magnetism.
Lavalier:
A small microphone, that can be worn around the neck on a cord or clipped to a shirt.
Noise:
Unwanted sound or static in an audio signal.
Pickup Pattern:
Defines a microphone’s response to sounds arriving from various directions or angles.
Sound Bite:
Any short audio segment for use in an edited program – usually a highlight taken from an interview.
On this microphone the pattern can be influenced by turning the knob from “tele to wide”.
Signal-to-Noise Ratio (S/N):
Relationship between signal strength and a medium’s inherent noise. Audio S/N specifies amount of background tape hiss present with low or no-volume recordings. Higher figures represent a cleaner signal. Usually cited in decibels (dB).
Wild Sound:
Audio recorded independently of picture i.e. rain on roof or clock.
In the 2nd part of this article I will elaborate, what you can do and how to apply several techniques to enhance audio in your video production and how poor sound captured during production can be salvaged in post production.
Remote not working, what now? – If a new universal controller is not an option
Jul 14th
dismantled remote control
You have replaced the batteries and the remote control is still not working, or just some keys don’t work. What else can I do? In most cases it is the remote control itself causing the trouble.
Why, somebody sat on it, it has been dropped, or some liquid has been spilled on it.
Since with most consumer electronic items an infrared system is used, we need to find out, if the remote is transmitting infrared light. That is easy. Find your camcorder or digital camera, position it in front of the remote controller and press the buttons. When the remote works, you see a pulsating light from the infrared diode behind the controller window.
Follow the steps below, if no light at all or only with some buttons.
IR LED
LED test setup
- Remove batteries
- Unscrew all screws you can find
- Dismantle the remote
Most controllers consist of two housing parts which hold a circuit board between them. Unclip top from bottom of the housing with a couple of screw drivers.
Firstly tension the battery terminals with a pair of pliers to ensure consistent power supply for the circuit board.
The keyboard is mostly made up of two parts, the circuit board itself with open contacts and a special rubber mat, which is positioned on top of these contacts.
It is dirt and liquid residue on the rubber mat as well as on the circuit board contacts, which is causing most of the problems. If you can use isopropyl alcohol, or any other cleaning fluid which doesn’t leave residue. Carefully wipe the whole circuit board and rubber mat with cotton buds or a clean tissue. Once the contacts on both sides are clean and dry, align the rubber mat with the contacts on the circuit board and assemble the controller. Check all buttons with your camera. If all light up the LED, you can go ahead and try the remote control on your CD-Player, camera, TV or…
By following this procedure, you have a good chance to keep your old remote controller in a good working condition.
LCD Side Screen Repair
Jul 9th
The glass layer of a LCD in often unprotected. A knock, or pressure on the screen breaks the glass.
Before you bring it to the repair shop, check all the other functions of the camera by using the AV-cables.
If there are other issues with the camera, it might be an uneconomical repair as these screen replacements can be very expensive.
Broken Side Screen
Side Screen without cover
LCD Panel
Choosing a Digital Point and Shoot Camera – What matters Most!
Jul 6th
Technician Camera Advice
This is not the usual camera test report, which ends up with a list of camera recommendations to buy. Rather, I would like to give you camera advice and the tools you need to choose your next digital camera today and in five years from now. Let’s face it, there are hundreds of different cameras to choose from and the manufacturers release new models every month. To make matters worse, most retailers stock different models, which makes price comparison almost impossible.
When it comes to choosing a new digital camera, you want to have knowledge on this subject, which can be applied as a foundation, before you start choosing brands and models.
shock and water proof extendable lens inbuilt lens
Choose the type of camera first!
It happens all the time – I see it almost every day. People come and see me with faulty point and shoot digital cameras, which have self induced faults. The good news is, that most of these expensive problems could have been avoided, when you had chosen the right camera type, which fits your lifestyle, and had taken the right precautions of course. The bad news is, these faults are not covered under warranty and are often uneconomical to repair!
What is a self induced fault? Sand -, liquid- and shock damage
- Sand damage can easily happen at the beach without realising it straight away. A couple of sand grains in the right spot can malfunction an extendable lens mechanism.
- The most common liquid damaged cameras we have seen are affected by rainwater, beach and swimming pool and believe it or not, drink bottles stored in the camera bag.
- Shock damage is a tricky subject, in particular when the camera is handled by multiple users. Often it is not realised, as there are hardly any signs of damage on the outside housing of the camera, but the damage is done inside.
What is an uneconomical repair?
The most common symptoms, or let us say parts, which brake, are LCD displays and extendable lenses. LCD’s are made of glass and exposed often without any protection. Lenses are in most cases none serviceable items and need to be replaced as a whole unit, which is extremely expensive. Spare part prices can make up to 50% and more of the price you payed, when the camera was new! Given the price decline and the improved performance of new cameras, you can work out by yourself, were you want to spend your money.
What to look out for when choosing your new camera?
To get the most out of your investment, choose the type which suits your lifestyle best. Let’s put the earlier paragraph about self induced faults into consideration and assume we distinguish between 3 types of point and shoot cameras. Cameras with…
- extendable lenses
- inbuilt lenses
- water and shockproof
If you have a personal preference for a camera with an extendable lens, you must take special care of it, to avoid any damage to the lens. (details here)
In case you have kids and multiple users, who might be a little rough with the handling of the camera, the best return on the investment is given with a water and shockproof camera. Personally I use a camera with an inbuilt lens, which hasn’t given me any problems whatsoever.
Accessories
Do you want to upgrade your camera with a newer model of the same brand and hoping to use your old accessories like battery or memory card? In most cases you can’t. Different physical shapes and electrical specifications make it impossible.
Features
Now, we are talking purchase price. More megapixels and optical zoom is not all! Often specifications are pushed to the limit and performance is sacrificed. Let me explain: to take a good shot with a high megapixel and let’s say 10x optical zoom camera without tripod requires a lot computer power. Often it can take a few seconds of shutter lag and the results are still not satisfying. What I am saying is, to have a good performance/specification camera you have to pay the price and go for a semi-professional or DSLR camera. However, the most shots indoors are taken in wide-angle lens setting and outdoors you use the same, most cameras handle these shots without any issues.
The best insurance from disappointments is to test the camera by yourself under different light conditions and zoom settings. (more details here).
Test reports
Make sure, the cameras tested are readily available and the test topics make sense and are relevant for you. See it as a guideline only.
What is a good brand?
This is hard to say from a repairer’s point of view, we only see the faulty ones. When looking underneath the brand badge and housing, it is almost impossible to see if a ‘brand name’ stands out with better workmanship. All I can see is, that mechanical components seemed to be done more out of plastics and the way they have been put together looks and feels cheaper as it used to. All the improvements, which lead to better specifications, go into more powerful electronics and computer chips. Therefore manufacturer costs can be reduced to a minimum. Today, it is not as expensive as it used to be to manufacture a relative good new camera or release new models, which explains the ever increasing flood of new cameras.
What the reliability of the different brands concerns, I couldn’t recommend one or the other, as long as you compare cameras in the same price bracket. A lot of spare parts have Chinese writing on the boxes, which makes me wonder, where there are coming from and where the cameras are manufactured.
Summary
Here you go – this is an opinion and camera advice from a repairer. I hope, it was helpful and has shed some light on this almost overwhelming task to purchase a new camera. There are certainly a few points above, which should be elaborated on. To get the full picture, visit me on my blog for a few more pieces of the puzzle. At the end of the day you want to educate yourself to be able to apply more common sense to make better decisions.
It is not always the cheapest price what matters, you want to have the right type of camera and value for your money.
Film and Television Technology Part 3 Television Production
Jul 2nd
Television Production
Students and experienced professionals in the video industry will find technical knowledge beneficial, as it helps to enhance your production skills and get the most out of your equipment. Discover how to tackle the technical challenges of making short films and videos, and help make every film you make a great one.
Why and how can you benefit?
I can’t stress this point enough; technical Know How gives you the flexibility to improvise, when things are not necessarily go according to plan. You can learn and adopt yourself faster, when working with new equipment. Advance your film making skills to the next level.
What is the purpose and benefit?
Know the operation and adjustment of a professional camcorder to a full production set-up including:
- Principles of manual adjustment to professional camcorders, and when to use them
- Different types of professional video formats, media, and their purpose
- Utilizing the features of your professional camcorder with confidence
- Identify the equipment required for different productions
- Understand the building blocks of a production setup
What topics should be covered?
To be really effective with your work, you should have the knowledge of:
Camera Functions (professional controls) Professional Video
ATW (Auto Tracing White Balance) Camera controller
AWB (Auto White Balance) & Preset White Tele prompter
Adaptive Highlight Control Formats
White Clip XDCAM / SD / HD / EX
Zebra Production
Black Balance Workflow & Equipment
Black Clip Professional Disc Media
Black Gamma Workflow and Editing
Black Shading Camera control configuration systems
Colour Bars TV Network
Sub-carrier Phase Control/Horizontal Event shooting
Phase Control
Crispening & More…
How to acquire the right knowledge?
Find a complete and thorough reference, that will teach you how to get the most out of your professional camcorder. Work with a guide on how to troubleshoot issues when filming, and how to set up a production shot.
Complement your film school knowledge with the technical aspects of film making.
A film school or college alternative when you need the education, not the degree
Don’t have the time and money to go to school.
Do you need to have results fast?
Do you prefer to learn at your own pace, whenever you want?
How about a home-study with various forms of delivery?
- A complete course with a PowerPoint presentation, as well as a full and complete e-book and complementary podcast.
- An e-book that provides an easy reference so you can find the information you need, quickly.
- The podcast is delivered as an mp3 file so you can easily listen to it from your computer, CD player, or on-the-go through an mp3 player or iPod.
- A course, delivered in straight forward, easy to follow language with many full colour illustrations to ensure maximum comprehension.
The benefits of a home-study:
- Self-Paced: no more rushing to complete assignments, or trying to squeeze your life in around your courses.
- Comprehensive Reference Materials: have everything you need to reinforce your learning handy, and take it with you for on-location reference.
- Easy Formats: view the presentation using just your web browser, and the e-book only requires Adobe Acrobat, which is a free download.
- Comprehensive: e-book, slide show, and podcast cover all angles, and provide multiple study methods for different types of learners.
- Affordable: home study courses are much more affordable then classroom driven courses at film school, so you can learn more for less.
Summary
For beginners, intermediate and advanced camera users a television production home study course will provide the final piece of the puzzle. Once completed all three parts of the home study, you will understand all aspects of filming: Television technology, colour reproduction and TV production. Thorough, affordable and simple to use, this is the answer for those, who want to enhance their technical and production skills.
A straight to the point, affordable and simple to use home study course can be your alternative
or better complementary technical education to college or film school.
Remember, extraordinary results is no accident, applied knowledge makes all the difference.
Film and Television technology Part 2 Television Colour Reproduction
Jul 2nd
Colour Reproduction
Due to the complex and comprehensive subject, colour or chroma reproduction is dealt with separately.
How the right colour is added, coded and transmitted is only one part, on the receiver end it needs to be decoded and displayed on your TV-screen. You should be familiar with all these steps above in order to judge and rectify any colour issues in your production.
Why should you know about television colour reproduction?
Multiple camera setups, different television standard, camera exposure can influence colour reproduction quite dramatically. Especially when you have to mix and match footage from different sources. Even exposure presets can influence the colour within a video clip. If you find it frustrating that the picture you film does not come across the way you want them to when viewed, then the right education is a good first step.
What is the purpose and benefit?
Let me summarise it this way: It is a challenge to go out and shoot new video scenes under difficult and mixed light conditions, or sitting in front of the computer in postproduction and trying to make the best of existing footage. When you know what you’re doing, you get the desired result faster.
What topics should be covered?
To be really effective with your work, you should have the knowledge of:
- Principles of light and colour
- How different colours are generated
- How colours are mixed and coded in video signal
- Results of influencing colors in cameras and TV receivers
- Composition of video signals at camera, VTR and TV receiver
- Specifications and differences of SD and HDV
- Building blocks of signal processing in camera and television
- Difference of PAL and NTSC television
- Troubleshooting colour problems in video production
- Terminology of different video signals
How to acquire the right knowledge?
Develop a base of colour fundamentals for television technology to enhance your skills.
Complement your film school knowledge with the technical aspects of film making.
A film school or college alternative
Don’t have the time and money to go to school.
Do you need to have results fast?
Do you prefer to learn at your own pace, whenever you want?
How about a home-study with various forms of delivery?
- A complete course with a PowerPoint presentation, as well as a full and complete e-book and complementary podcast.
- An e-book that provides an easy reference so you can find the information you need, quickly.
- The podcast is delivered as a mp3 file so you can easily listen to it from your computer, CD player, or on-the-go through an mp3 player or iPod.
- A course, delivered in straight forward, easy to follow language with many full colour illustrations to ensure maximum comprehension.
The benefits of a home-study:
- Self-Paced: no more rushing to complete assignments, or trying to squeeze your life in around your courses.
- Comprehensive Reference Materials: have everything you need to reinforce your learning handy, and take it with you for on-location reference.
- Easy Formats: view the presentation using just your web browser, and the e-book only requires Adobe Acrobat, which is a free download.
- Comprehensive: e-book, slide show, and podcast cover all angles, and provide multiple study methods for different types of learners.
- Affordable: home study courses are much more affordable then classroom driven courses at film school so you can learn more for less.
Summary
A course, which provides you a great technical background, you may have found lacking when
producing a film. A straight to the point, affordable and simple to use home study course can
be your alternative or better complementary technical education to college or film school.
Remember, extraordinary results is no accident, applied knowledge makes all the difference.
Film and Television Technology
Jul 2nd
Television Technology
Part 1 Television Technology
is for any beginner film maker, who wants to have a solid technical foundation to build on. It is also recommended to those, who feel to need a refresher on the fundamentals of film and television technology. This is the first module of a three part series.
Why should you have a strong technical foundation of Film and Television?
Someone could argue technology is changing so fast, that you have a hard time to keep up. Everything is done with sophisticated computer chips in a ‘black box’. The only thing you should know is what goes in and what comes out. It is more beneficial to concentrate on the filming techniques in order to move ahead.
This is exactly what the sales and advertising industry relies on, a technical more or less uneducated buyer, who can be manipulated with clever commercials and adverting to buy certain products.
The benefits of technical ‘Know How’
You don’t have to rely on the ‘experts’, who want to sell you anything. Instead you can add your own knowledge to make a more accurate decision. Let me put it this way; it serves like a compass, which navigates you through the ever increasing info and products for sale.
If you are, or want to become a television professional – communicate effectively with technical staff and do some trouble shooting, or perhaps solve a technical challenge, you need to know the technical fundamentals of television broadcast.
You have to understand the basics of how an image is generated, recorded, transmitted and is viewed. Develop a base of technical fundamentals for television technology to enhance your skills.
Complement your film school knowledge with the technical aspects of film making.
A film school or college alternative
Don’t have the time and money to go to school.
Do you need to have results fast?
Do you prefer to learn at your own pace, whenever you want?
How about a home-study with various forms of delivery?
- A complete course with a PowerPoint presentation, as well as a full and complete e-book and complementary podcast.
- An e-book that provides an easy reference so you can find the information you need, quickly.
- The podcast is delivered as a mp3 file so you can easily listen to it from your computer, CD player, or on-the-go through an mp3 player or iPod.
- A course, delivered in straight forward, easy to follow language with many full colour illustrations to ensure maximum comprehension.
The benefits of a home-study:
- Self-Paced: no more rushing to complete assignments, or trying to squeeze your life in around your courses.
- Comprehensive Reference Materials: have everything you need to reinforce your learning handy, and take it with you for on-location reference.
- Easy Formats: view the presentation using just your web browser, and the e-book only requires Adobe Acrobat, which is a free download.
- Comprehensive: e-book, slide show, and podcast cover all angles, and provide multiple study methods for different types of learners.
- Affordable: home study courses are much more affordable then classroom driven courses at film school so you can learn more for less.
What topics should be covered?
- TV-Principles and transmission
- Scanning – interlaced/progressive
- Video-, and frequency modulation
- Vertical-, and horizontal synchronisation
- Camera and monitors
Summary
A course, which provides you a great technical background, you may have found lacking when
producing a film. A straight to the point, affordable and simple to use home study course can
be your alternative or better complementary technical education to college or film school.
Remember, extraordinary results is no accident, applied knowledge makes all the difference.
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