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| urbanfox.tv > technology articles > camera articles > guide to buying a HDV and DVPRO camera |
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WHAT IS ON OFFER?JVC was the first company to launch an HDV camera, the JY-HD10. However, it only has a single CCD imaging chip and so hasn't really attracted the attention of programme makers. Sony has two smaller, single CMOS chipped HDV cameras, the "professional" HVR-A1E (with XLR inputs) and the HDR-HC1E (a consumer version, without XLRs), however, this page will concentrate on the 3-chip professional versions.
All of these cameras are now on sale somewhere in the world. So, if you are thinking of buying a camera this year - I've added a comparison table below - based on information currently available. If money isn't burning a hole in your pocket here are a few things to consider before buying...
i for interlaced - p for progressive.Interlacing is a clever technical trick used to minimize picture flicker on your TV. With interlaced scanning, a TV frame is composed of two fields. One field is made up of all the odd numbered lines, while the other field is made up of all the even numbered lines. These interlaced fields are usually refered to as 50i for PAL shooting (60i in NTSC) and the frame rate is very similar to how the eye sees the world (giving a natural-looking motion blur). If you have an old fashioned (CRT) TV - and watch the news and docs then you are watching interlaced pictures. Progressive scanning scans the whole picture frame from top to bottom (like reading a book). If you watch programmes on a Plasma screen, LCD or DLP (Digital Light Projector), then you've already been watching pictures displayed in a progressive mode (although not necessarily recorded progressively). With cameras, progressive scanning usually leaves us with 25 frames, often refered to as 25p (30p in NTSC). This gets some people very excited, because film is also shot at 24 (or 25) frames per second. A camera that shoots true 24/25p will give you a film look without all the costs associated with film production. If you are on a low budget and want to make video look like film make sure the camera shoots true 24p or 25p. The JVC HD100 and HD101 does. The Sony Z1 and Canon XLH1 do not. The Sony has a cineframe option and Canon just calls it Frame and refer to it in its specs as 25f (to distinguish it from true progressive - 25p). See Adam Wilt's site for his explanation on what Sony's cineframe is all about. The jury is still out on how Panasonic will process 24/25p. For a very good explanation with animated pictures on progressive and interlaced pictures see www.avdeals.ca/classroom/Proscanexplained.htm - it is more biased to the American audience but the explanation should still be of use to us PAL people. There is also a good explanation of interlaced and progressive scan at Avis communications. I'd also recommend you look at the excellent Ken Stone site for more info on 24/25p and editing (with Final Cut Pro)
525 (480), 625 (576), 720 and 1080These numbers all refer to the number of picture lines that make up your TV image. Standard definition (SD) PAL is 625 lines (576 active lines) while NTSC uses 525 lines (480 active lines). For the size of CRT TV that fits in most people's living rooms - this number of lines has given us good, watchable pictures for quite a few years (at least it has in PAL). But, TV sets are getting bigger, so pictures need to be better (ie have more lines) in order to really impress the neighbours. High definition (HD) uses either 720 or 1080 lines. Here the number of lines has nothing to do with the legacy of PAL or NTSC transmission systems. In fact BSkyB (in the UK) has announced that it will broadcast using both 720p and 1080i in its subscription service being launched in 2006. There are other higher definition recording systems available (aimed initially at digital film production) that go above 1080i, while 1080/50p or 60p is what many European broadcasters hope will become the norm for high-end TV production within a few years. The new cameras on this page will all shoot in SD and HD. The question really is which HD do you want to record in? 720p (ie JVC and Panasonic) or 1080i (Sony, Canon and Panasonic). There is some good basic info on TV lines at www.internetcampus.org/tvp009.htm and www.internetcampus.org/tvp008.htm
COMPARISON CHARTThis comparison chart compares the most most important features when choosing a camera for picture quality.
DV, DVCAM, HDV or DVCPRO HD[If you're budget doesn't quite stretch to HDV then I recommend you go the our DV buying guide page ] There is a lot of confusion about these formats. DV and DVCAM use the same video codec and, so, offer the same picture quality. The big difference is that the tape runs faster through the camera in DVCAM, which makes it more robust in the event of dropout and less prone to compatibility problems. DV and DVCAM record standard definition TV pictures (in 4:3 and 16:9). DVCAM is Sony's professional version of DV and DVCPRO is Panasonic's. DV, DVCAM and DVCPRO all use the same video and audio codec. For those of you who want to compare all three, and check out the differences, take a look at the extensive table on the video university site. DVCPRO comes in three flavours:
HDV is a new recording format developed by a consortium of manufacturers including Sony, JVC, Canon and Sharp. HDV is a high-definition version of DV, which can record in either 720 lines (HDV1), at 19Mbps, or 1080 lines (HDV2), at 25Mbps. HDV gives higher resolution pictures but still records them on a miniDV or DVCAM tape. DV, DVCAM and DVCPRO (25, 50 and HD) record whole frames onto the tape, with each frame being compressed to get all that information onto the miniDV tape. The amount of data created in HDV is far greater than in DV (or DVCAM) but it still has to fit on the same little tape. So, the engineers had to find a way to more efficiently compress all that information. Step forward MPEG2 long GoP encoding. With this compression, the camera does not record every frame of video. It records occasional key frames and just enough other information to enable it to recreate the rest. The video between one key frame and the next is called a Group of Pictures (or GoP). A Group of Pictures consists of three types of frames - the I-frame, P-frame and B-frame. (Intra frame, predictive frame and backwardly predictive frame.) A typical GOP consisting of 12 frames will be: I B B P B B P B B P B B The I-frame holds the most information and is the largest frame size in terms of data.The P-frame is compressed further and holds less information than the I-frame. It predicts what will make up the image from the previous I-frame or P-frame. Then comes the B-frame, which holds the least amount of information. It is calculated by forward and backward prediction to the I-frames and P-frames or even an estimate of the in between value of them. In DV or DVCAM, a small amount of dirt on the heads when recording could result in dropout problems on a single frame only, because each frame is independent of the other. With MPEG2 a small bit of dirt causing dropout on an I-frame could affect half a second of video, ie the whole GoP. This is why Sony manufactures a brand of miniDV tape just for HDV – which it claims will be more reliable. MPEG2 also causes software writers, designing editing software, sleepless nights. Only the I- frames hold all the picture information – but when editing you want to edit between any frame. Final Cut Pro 5 edits native HDV - but requires a lot of processing power to do it, as it has to look at all of the GoP at once, and calculate a complete frame for each of them, so that the instant you edit, it can offer you an accurate full frame picture. If you are thinking of buying FCP5 do make sure you have a fast enough processor to do the calculations. For example, while a PowerBook could cope with perhaps four or five streams of DV at once, it will only be able to do two streams of HDV, because the software has to work an awful lot harder. Apple's iMovie and Final Cut Express use the Apple Intermediate Codec, which transforms HDV into individual frames as the video is played into the computer. While this is more efficient for the processor, the decoding and subsequent re-encoding to HDV not only takes time, but also results in a slight loss of quality. There are ways of importing HDV into almost all editing systems, some using their own codecs, like AIC, and a small number doing (or promising they will do) native HDV editing. Many editors upconvert their HDV footage to DVCPRO HD for editing (see below). It also has the advantage of being 4:2:2, which means it retains a lot more colour information, which is handy if you are doing graphics or effects. Another problem with the GoP form of compression comes when you pan, tilt or zoom the camera. During a camera move every pixel making up the image will change from frame to frame. But, we know that not every frame holds all the information needed. The result is that picture resolution will be best at the static start and end of the shot and not so good in between. However, in all the shooting I've done, I haven't seen any artefacts. DVCPRO HD uses less compression than HDV, as it has at least four times the bandwidth (100Mbps compared to either 25Mbps for 1080i or 19Mbps for 720p). Although it might seem that this would mean that an editing system will find it more difficult to handle lots of streams of DVCPRO HD than HDV, this is not the case. The limitation here is on the transfer of video from the hard drive rather than processing power, as the processor works a lot less hard when dealing with the individual frames of DVCPRO HD. If you do multicamera editing in DVCPRO HD, then a fast RAID disk array presents a good upgrade path if your system starts to struggle (presuming you have a high-spec PC or Mac in the first place). For a good background check on DVCPRO also read A Sound Person's Guide To Video article. SDI stands for Serial Digital Interface (also known as CCIR 601). It is the broadcast standard for interfacing uncompressed video, from cameras, VTRs, etc. HD SDI is the HD version of SDI, and offers a throughput of almost 1.5Gbps. Only Canon offers this directly from the camera within this budget, although you can access the raw 720p HD on JVC's HD100 or 101, but will need to put this through an HDV to HDSDI bridge (which cost from about £750 to £2,000).
4:2:0 and 4:2:2 or Y:Cb:CrYou will notice numbers like these bandied about above. The first number (Y) represents brightness or luminance (or what engineers call luma), The next number (Cb) is the blue signal minus luma (B-Y) and the third number (Cr) is red minus luma (R-Y). Phew. If you really want to know the details take a brave look at Adam Wilt's site again and www.answers.com/topic/ycbcr-sampling. You might also want to check out our article on the pros and cons of each. Why are these numbers important? Well, they give us a way of comparing how much colour information is left in our recorded pictures. 4:2:2 sampling is used for DVCPRO50, DVCPRO HD (and Digital Betacam) 4:1:1 sampling is used in DVCPRO25 and DVCAM (NTSC) 4:2:0 sampling is used in DV and DVCAM (PAL) The zero doesn't mean there is no colour info - but it does explain why DV is difficult to use for green/blue screen work - there just isn't enough colour info to work with. Although there is software that will allow you get a usable chromakey picture from a DV signal (such as Serious Magic's Ultra 2), if you want to do realistic effects, compositing and graphics work, then 4:2:2 will be an important consideration. In our group of cameras the Panasonic HVX200 and Canon XL-H1 are capable of 4:2:2 sampling.
CCD and CMOSThe CCDs (Charge Coupled Devices) convert light into an electrical signal - they are the electronic version of film in a cine camera. For professional results, you need three CCD chips (one each for red, green and blue light). Single chip cameras (generally) belong in the domestic market.When it comes to CCDs, size matters. Bigger is better. Most prosumer cameras use 1/4-inch CCDs. All of the models in our chart have 1/3-inch CCDs. In comparison the Digibeta camera has 2/3-inch CCDs. A larger CCD always results in better pictures, even if the pixel count is the same. Chip size also has an effect on Depth of Field. Small chips increase DoF even if you are shooting on a wide aperture. For the beginner this can be great because increased DoF means that it is harder to get out of focus pictures. But, for the more experienced user, it can be frustrating. Some of that elusive film look we mentioned earlier is achieved with shallow DoF. That's not to say that it is impossible to get a shallow DoF - just more difficult. Extra Neutral Density filters and working at the narrow end of the lens will help. There are also third-party add ons (such as the Mini35 Digital adapter from P+S Technik) that allow you to use larger lenses and get shallower DoF. You might also see the acronyms IT (Interline Transfer) and FIT (Frame Interline Transfer) bandied about. FIT CCDs are better than IT, because they are more resistant to vertical smear (which shows up if you point the camera at lights), but both have improved so much recently that this is hardly a problem. CMOS (Complementary Metal Oxide Semiconductor) sensors are an alternative to the CCD. They allow more individual light sensors per square centimeter than CCD, and offer a wider dynamic light range, for better detail in both shadows and highlights, and are less susceptible to vertical smear. They are still being perfected (especially by ARRI with its high-end digital film camera, the D20). They do offer higher resolution (and good multi-resolution handling) at lower costs, which is why they are now being introduced into digital stills cameras. Sony has two HDV single CMOS cameras the A1 and the C1. They are very small - with only a single chip there is no need for a beam splitter - to split the light into red, green and blue (which makes the 3-chip cameras bulkier)
WIDESCREENCCD shape is also important, traditional 4:3 aspect ratio pictures are on the way out. In the UK, the broadcasters (BBC, ITV, C4, etc.) do not want and won't accept new material shot 4:3. Everything has to be delivered in 16:9.HD does not exist in 4:3 - it only comes in 16:9. This is why all of the models in our chart are 16:9. However, they can be switched to SD 4:3 mode.
THE LENSMost prosumer cameras have built-in lenses that cannot be changed. Quite often they don't zoom out wide enough, so there are now wide angle adapters being introduced for these cameras.The JVC HD100/101 and the Canon XLH1 both have interchangeable lenses. The JVC will take any 1/2 inch C mount lenses and there are now adaptors so that you can fit a whole range of other lenses too. Geat news if you already own some professional lenses and are planning to use the JVC as a second camera. The XL H1 comes with a 20x HD Canon lens and there will be a range of Canon lenses to choose from. You can also use your old XL2 lenses - however, Canon believes you should only use those in SD mode. For HD recording stick with the HD lenses. Do make sure you know how to check the back focus if you buy one of these cameras. There is a guide to correcting back focus on my DSR500 page. It is difficult to cover all eventualities with one lens. Most professionals have at least two zoom lenses - one biased towards telephoto and another that goes very wide. Do check how your lens behaves at the extremities. As you zoom out, you may notice that strong verticals become curved (barreling) and that the corners of the picture get darker (vignetting). When you zoom in, the picture may get slightly darker (lens ramping). A good lens minimises all these characteristics.
LOW LIGHTIf you intend to do a lot of night shooting the camera's performance in low light is important.If you get a chance to check out cameras at a trade show, notice how bright the stage sets are. Then note the f number on the lens. Most will be around f8 or f11 (i.e. a small aperture). Pictures always look great with a well lit subject. If possible, pan the camera round to a dark area of the hall (adjust the iris accordingly) and check picture quality in low light. Does it still look good? How sensitive is the camera? Did you need to add some gain? If so, how much? If you check the various fora on the Sony FX1 and Z1 you'll find that, disappointingly, these cameras are not as good in low light as the Sony PD150. However, the new Sony compact HDV camcorders feature Sony's Nightshot technology (as used on some of its digital stills cameras), which could be useful in very low light conditions.
THE VIEWFINDERUsually overlooked, a good viewfinder is vital. The best gives you control over brightness and contrast.With HD pictures, focusing is critical. One way that the manufacturer can help is to offer peaking (edge enhancement) in the picture. The FX1, Z1 and XLH1 have an adjustable peaking option. They also have an Expanded Focus button that digitally zooms into the picture, to help you check focus in greater detail. The JVC HD100/101 has it's "patented Focus Assist function". This switches the LCD display or viewfinder to monochrome, and then uses peaking (in your choice of colour - green, blue or orange), to show what is in focus. Unlike the Sony system, you can use it while recording, just switching it in and out as necessary. Details of the Panasonic HVX200 system are limited, but it does have a button on the back marked "EVF DTL", which I assume stands for electronic viewfinder detail, which is peaking by another name. All the cameras with pull out screens use LCDs of the same size - 3.5 inches. Most LCD screens are difficult to see in bright sunlight, so you may want to buy a cover to shade it and improve picture quality. The Hoodman is simple but effective - check it out at www.hoodmanusa.com. Petrol also does a sun shade, click on the accessories tab on its website. The Panasonic HVX200 has a 4:3 LCD screen. At first this seems odd - until you switch on. The 16:9 picture sits letterboxed inside the 4:3 screen, with all the timecode, battery information, f-No, etc., are placed in the black redundant areas of the screen, so, for the first time ever, you have a clean picture free of distractions.
AUDIO INPUTAll of these cameras offer high quality 16-bit, 48kHz audio sampling. The Sony FX1 doesn't really fit the definition of professional because you cannot plug in professional microphones with XLRs and it does not have phantom power (essential for all gun mics), unless you add on a sound box like the Beach Tek (do make sure you get the one with phantom power if you own a gun mic). If you are going to that expense you might as well save up and buy the Z1.Virtually all professional mics come with XLR connectors, so I would hightly recommend you only buy a camera with XLR sockets because these are more robust than other audio sockets. The Z1, HD100, XL H1 and HVX200 all have two XLR sockets, phantom power and auto/manual level control.
INPUT/OUTPUTComponent, RCA Phono, S-Video or FireWire. There are several ways to take pictures out of the camera, besides ejecting the tape. All of these cameras have a FireWire IEEE-1394 connection (the four-pin unpowered version is called i-Link by Sony). This allows you to play straight from the camera into an editing system - handy if you use a laptop to edit on location. In Europe, because of a 15% duty on cameras that can work as video recorders (ie have FireWire in and out), JVC offers two versions. The HD100 (without FireWire input - ie output only) and the HD101 (comes with full i/o). If you want to use the camcorder with JVC's adaption of the Firestore hard disk unit, then buy the HD 101 so that you can review the pictures you record on it....Only one of these cameras, the Canon XL-H1 has outputs and inputs that enable you to link two cameras together to lock free run timecode. This is very useful for multicam shoots and was previously only available on more expensive cameras. The XL-H1 is also the only camera to off HD SDI output. This allows you to take the uncompressed HD output straight from the camera. However, you will need an expensive SDI interface to input the signal into your computer for editing.
SHUTTERI think the shutter on video cameras is slightly overrated. You rarely need the wide range of speeds they offer. However, they are useful for fast moving sports like tennis and cricket (to reduce motion blur), where the ball travels at over 90 mph. While slow shutter speeds can be useful for an occasional dream-like effect.More useful is the ability to shoot computer screens without flicker. For that you'll need a camera with a clear scan or synchroscan (variable shutter) option that increases in small increments so you can sync the shutter speed with the computer screen refresh rate. The JVC HD100 has variable scan from 50.2 - 1,973.7Hz which should sort out all computer screens. My guess is that both the Panasonic and Canon XL H1 will have synchroscan because their predecessors, the DVX100 and XL2, do. Unfortunately the FX1 and Z1 do not have an easy way to deal with computer flicker. However, if you go to my online training manual I have a trick that does the job .
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| More...
Guide to buying a DV (DVCAM)
camera.
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August 2005 |
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Buying
an HDV or DVCPRO HD Camera kit.
In
September 2004 Sony launched the
HDR-FX1, its "consumer" 3-CCD HDV camera. If
you have been happy using the VX2000 (and VX2100) then you should
definitely look at this camera. Unfortunately, it does not have
XLR sound inputs - this is one of the reasons why it is labelled
a consumer camera. The more professional version is the Sony HVR-Z1, which
was launched in February 2005 and has the much needed XLRs.
If you are a seasoned PD150 or PD170 user you'll find this is
a natural progression. This is a documentary makers' camera.
It records in HDV (1080i), DVCAM and DV formats - plus it can
also be easily switched from PAL to NTSC, very useful if you
have clients all over the world. The Sony Z1 does not
produce true progressive images (
Panasonic
has also announced a new camera, the AG-HVX200. This has been
launched in the USA and should be in the UK soon. Some people mistakenly
think this is an HDV camera. It isn't - potentially it is better! It
records using the DVCPRO HD format (as well as DVCPRO). It's other
interesting feature is that it 
We
finally have an HDV camera from Canon, the
XL H1. This is the long-awaited successor to the
XL2 (although Canon don't expect to stop producing the XL2). It
is HDV and 1080i. Like the Sony Z1, it does not have true progressive
scan. So, those of you that wanted that (progressive) film look
may be disappointed. One of its most interesting features is 