In this article, you will expect an explanation about the following features of an HD Camera:
- What is Interlaced/progressive?
- What are SD, HD, PAL, NTSC?
- What are DV, DVCAM, HDV, DVCPRO?
- What is Y:Cb:Cr for?
- What is the different between CCD and CMOS?
- What is 4:3/16:9?
- What is there to know about lenses?
- What are audio inputs?
- What are the input/output?
Looks like we have a lot to cover, we should be getting started by now!
When you are starting your own production, one of the most critical equipment you will have to invest in is an HD (High Definition) Camera. This article discusses the things you will want to consider before buying or if you already have bought one, this should guide you in knowing more about your equipment. While you are on your post production stage, it's quite frustrating to realize that your footages don't go well as expected. Sometimes the frames are bigger, the color is not that rich, color keying is not that smooth, and a lot of different things you haven't any clue. Finally, after arguing and blaming your editor, you came to a conclusion that the camera was to blame! You just overlooked some of the critical features of you camera. Let's discuss them here one by one.
Interlaced or Progressive
Interlaced and progressive simply tells you how the picture is refreshed on screen. Progressive is easier to understand, one frame comes after the other, that's it! But with interlaced the frame comes in parts. Imagine the cathode ray scanning the screen line by line. In progressive, the lines are done sequentially without skipping. It's not a lot of hard work but a Russian inventor figured out a way to skip the odd and even lines without much loss of quality thus reducing the bandwidth to half. The disadvantage of course is the flickering you see on your standard television. Go ahead, look closely at your TV screens and you will notice two bands. This is how interlacing work.
Thus, you will see 1080p, 720p, 576i in your HD camera. But you might ask what the numbers stand for. 1080, 720, and a lot more variation on different cams, stand for the vertical scan lines. So if you see 1080p, it means that the camera will record in progressive mode with 1080 vertical scan lines. And the higher scan lines there are the more quality you can capture for editing purposes.
A lot of HD cameras have different modes. So when buying one, consider which mode would go well with your projects.
SD, HD, NTSC, PAL
SD stands for Standard Definition, an old viewing, storage, and transmission systems when color TV was introduced. It has a 4:3 aspect ratio and 480 interlaced scanning lines. This is pretty much the lowest you can go in terms of quality, anything lower than this would probably better on a computer screen rather than a television.
HD stands for High Definition, any that has a higher resolution than SD is considered HD but the most common that you will see are 1280x720px (720i) or 1920x1080px (1080i/1080p) in 16:9 aspect ratio. This is what they use in film making and it makes the difference when editing as well. You will most likely notice, just by looking at the quality, if the footage was shot in an SD or HD camera.
NTSC stands for National Television System Committee that runs at a frame rate of 30fps (frames per second) or 29.97fps to be exact. This is widely used in Japan, Philippines, South Korea, Taiwan, Burma, and some Pacific islands.
PAL stands for Phase Alternating Line that runs at a frame rate of 25fps and more widely used around the world than NTSC.
SD and HD is concerned more of the quality of a single frame as HD have more pixels to store into compared to SD, while NTSC and PAL are more concerned on how fluid the frames go together as the more frames there are the more fluid the would look like. But in NTSC and PAL, you should just concern yourself on which country it is used and not to mind about the other details. There isn't much of a difference in the frame rate anyway so nobody will see a difference. However, PAL is more superior as it answers most problems that NTSC has.
DV, HDV, DVCAM, DVCPRO
DV stands for Digital , a type of recording system that works by using digital rather than analog signal. This has become the standard for home and semi-professional users as well as independent filmmakers because of its quality compared to analog.
HDV stands for High-Definition , a type of recording and playback. It is far more superior than DV which is at 480i, thus acceptable to professional editing production. The two major versions of HDV are HDV 720p and HDV 1080i.
DVCAM stands for Digital Camera, a professional variation of DV which is 50% faster having 50% wider track, thus reducing the chances of dropout errors. One of the features of this format is its ability to lock audio. You will notice that recording DV on several generations will cause the audio to off-sync, in DVCAM, this does not happen.
DVCPRO stands for Digital Cassette Professional, developed by Panasonic specifically for Electronic News Gathering. It has a greater track compared to DVCAM and uses a different type of tape.
All of these are recording system formats. Starting from DV, it evolved into a more sophisticated system giving greater quality. If you are considering covering parties or doing an independent film with low budget, you could go with the DV. It's acceptable in terms of quality and price range. But for professional production, the format starts at HDV all the way to DVCPRO. You will need this for broadcast quality output such as television, commercials, and probably covering big events which has high-quality standard requirements.
Y:Cb:Cr
Sometimes, you will see in the specifications numbers that look like these 4:2:2, 4:1:1, or 4:2:0. This tells us how much color information is stored during recording. Y is for luminance (brightness), Cb is for Blue minus Luma (B-Y), and Cr is for Red minus Luma (R-Y)
- 4:2:0 sampling is for DV and DVCAM (PAL)
- 4:1.1 sampling is for DVCPRO25 and DVCAM (NTSC)
- 4:2:2 sampling is for DVCPRO50 and DVCPRO HD
Consider the 4:2:2 sampling if you will be compositing, doing realistic effects, and graphics. This has the highest color information compared to the others. This also explains why DV formats are harder to key out in green/blue screens. It's because there is not enough color information to work with.
CCD and CMOS
CCD stands for Charged Coupled Devices, it converts light into electrical signals. Most consumer cameras have single chips or 1CCD. But professional cameras have 3CCD, one chip for each color: red, green, and blue. And when it comes to CCD, the bigger the better, there are 1/4 inch, 1/3 inch, and 2/3 inch CCD's. Even with the same pixel count, larger CCD's always results to better pictures.
CMOS stands for Complementary Metal Oxide Semiconductor, it's an alternative to the CCD. They allow more individual light sensors, offer a wider dynamic light range, and are less susceptible to vertical smears (it's the vertical lines that appear when you point a camera to a light source).
Basically the ones above determine the richness of light that comes in. You might want to consider buying a 3CCD or a CMOS featured camera for a more professional look.
4:3 or 16:9
These are the most common pixel aspect ratios used. Although there are also other ratios in the early days of production, these two became almost the standards.
4:3 or Academy Ratio is used in SD and in standard television sets, while 16:9 or Widescreen is the international standard format of HDTV.
When choosing an aspect ratio, consider on which screen the will be played. Professional cameras have both these modes so you can switch between the two but widescreen has been used mostly nowadays since LCD and televisions have been switching to widescreen format as well.
Lens
There is no one lens that fits all purpose. Most professional graphers use one lens biased towards telephoto and another that goes very wide. However prosumer cameras do not have this option since their lenses are built-in so they don't zoom wide enough, though there are wide angle adaptors available out there.
To be sure, check how your lenses behave at the extremes. As you zoom out, you might notice barreling (verticals become curved at the sides) or vignetting (corners become darker). You can tell the lens is good if it minimizes these characteristics.
Audio input
Let me orient you first on the types of audio inputs in cameras. First we have the "minis", the ones you see in your iPods. These are also called TRS (Tip, Ring, and Sleeve), derived from its conducting parts. They come in mono and stereo with sizes such as 2.5mm, 3.5mm, and 6.3mm. All cameras should have at least this type of audio input. Secondly, we have the RCA (Radio Corporation of America) audio inputs, the ones you see at the back of your TV and VCR's colored red, white, or black most of the time. Thirdly, the XLR sockets, these are the ones you see when you have a handheld microphone that detaches from its cord. See the bottom of the microphone after you detach it? That's how it looks like in your camera. These are the ones used by professionals.
When you buy a camera, it always has a built-in microphone. But it is omnidirectional or it can pick up all surrounding sounds, even the ones you don't like such as background noises. Thus, you might want to buy professional microphones. And these microphones have either stereo TRS connectors (i.e. lavaliers or lapels) or XLR plugs (i.e. shotgun mics). So better have an HD camera which is capable of handling this audio equipment because you will need it.
Input Output
We have Component, RCA Phono, S- or FireWire. When editing, you will most likely need FireWire, but nowadays, most HD cameras has this so you don't need to worry. Other inputs outputs are analog so don't bother yourself about this unless you want to show the whole footage raw directly to a television or while covering an event. FireWire becomes really handy when editing on location since it can plug on your laptop directly, assuming that you have a FireWire input. You can also have your edited stored on a DV tape using FireWire.
And there you have it. I hope that next time you walk into a store looking for an HD camera, you won't be confused with the specifications and you are more confident about purchasing. Come and visit me at my blog to know more about production editing as I discuss these things in detail.
Hermie Cabrito is a editor and a motion graphics artist. Visit Production Editing and sign-up on a 5-week newsletter or the RSS feed for more related tips on production editing.
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