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JVC GY-HD Series Camera Systems
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Old May 3rd, 2007, 06:30 PM   #1
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Some general questions

1. What is scan matching? I can't find an explanation anywhere on the web. Some cameras have it, others don't. Is it worth having?

2. I need a prosumer videocamera that has a stereo mini-jack, so I can attach a lav mic I have. The two camers I'm looking at are listed as having a stereo mini-jack that is an "output" and not "input." Can I still use it with my lav mic?

3. Bottom line. Simple question. Which looks better: 720 lines of horizontal resolution or 1080 lines of horizontal resolution. I have researched this issue of progressive scan vs. interlaced scan and it's only left me more confused. Could somebody please explain it to me like I'm four years old?
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Old May 3rd, 2007, 06:44 PM   #2
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I can only sort of give an answer to 1.

I think scan matching is mainly a VERY handy feature when you're filming in an environment which has a lot of CRT-screens (the big computer screens, with a cathode tube in them). As these screens cycle at a different refresh rate from what the camera registers, having this scan matching can/should reduce a lot of the flicker that is usually there when you're shooting someone in front or next to a crt-screen.

Nowadays, with more people buying LCD screens for both television and computer, this is less and less of an issue.

Another use is - if I'm not mistaken - that you can tweak it when you're filming with fluorescent light, ie. TL-lamps. These also work with frequencies, that can cause flickering in-camera. Scan matching should again come in handy here.

So, it doesn't necessarily have anything to with progressive vs. interlaced.

Quote:
Originally Posted by Philip Brubaker View Post
2. I need a prosumer videocamera that has a stereo mini-jack, so I can attach a lav mic I have. The two camers I'm looking at are listed as having a stereo mini-jack that is an "output" and not "input." Can I still use it with my lav mic?
In short: No.
In long: No, because the output will enable you to plug in a headphone, to monitor the sound that it picks up through the microphone (built-in or external).
Maybe you can find an adapter that lets you connect it to the camera that you have your eyes on.

Maybe you could also tell us what cameras you are currently looking at.
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Old May 3rd, 2007, 09:26 PM   #3
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JVC GYHD110U questions

Hi, thanks for the prompt response. I, too thought that the "output" jack could not be used for "input" mics, but I was confused because bhphoto.com lists the specs as having the Stereo mini output AND (2) headphone outputs! Like I said in the last post, I have a lav mic with a mini-jack that I would like to be able to use with this camera. Anybody know of an adapter that can be used for this?

As I posted in the message title, I am seriously looking at the JVC-GYHD110U. The only things holding me back are the mini-jack (I know it's not that big a deal, but I still want it) and the fact that the horizontal resolution is 720 compared to Sony HVR-A1U which has 1080.

Which looks better: 720 lines of horizontal resolution or 1080 lines of horizontal resolution. I have researched this issue of progressive scan vs. interlaced scan and it's only left me more confused. Could somebody please explain it to me like I'm four years old?
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Old May 3rd, 2007, 10:19 PM   #4
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You do know they make a mini to XLR converter or any other type of converter you may need. Don't let THAT influence what camera you eventually get, aside from having the ability to capture great sound.
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Old May 3rd, 2007, 10:22 PM   #5
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You have to understand that 720p and 1080i are equal to each other in terms of bandwidth and datarate. It's not a question of the number of lines (720 vs. 1080). Instead it's a question of camera ergonomics, comfort and familiarity with the system and the workflow. If it all possible, try before you buy.

It's a serious mistake to get hung up on numbers (720 vs. 1080). Both are HD.

You can't say whether one "looks better" than the other, because if you could, then the other wouldn't sell. Both 720p and 1080i camera systems sell very well. It's just a matter of which one is right *for you.* There is no right or wrong answer, only subjective preferences.
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Old May 3rd, 2007, 11:06 PM   #6
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720 and 1080 refer to the scan lines which are horizontal. Draw lines horizontally across the TV screen one on top of each other. You either get 720 lines stacked on top of each other or 540 odd and 540 even interlaced lines. There are 1080 but only 540 are there at any one time. They cycle every 1/60 of a second. Thus the number 720 and 1080 are not really horizontal resolution but vertical resolution. Further complicated by whether these are progressive scan lines( the whole screen is scaned at once, 720P) or interlaced scan lines( odd and then even lines are scaned 1080i). For a number of reasons the actual vertical resolution between the two isnt too different as percieved by a humans eyes with individual frames being very sharp for the 720P but overall resolution may be greater for 1080i.

To further complicate the issue as with all equipment what the spec says and what any piece of equipment can do are two very different things entirely. The scan system is fixed but the horizontal resolution( how many pixels can one place next to each other across each of these horizontal lines that are stacked one on top of each other) will be governed by the camera imager , lens etc etc. The output will fit into the prescribed scan system but for instance one could get a HD camera with poor horizontal resolution. The scan system is the timeing mechanism so is fixed but one could get say horizontal resolution of say 600 with scan system of 720P or 1080i, just because the imager and lens isn't up to meeting the spec. I am sure you remember VHS cameras that had problems achieving 230lines of horizontal resolution but they met the interlace spec of 525 lines!!!!! The same is true for HD.

So symplistically one cannot compare the two directly one can only look at the output produced by specific cameras whatever their system because there can be good and bad for each system.

If you are a pure numbers person then as percieved by us humans there will be more pixels possible on the screen for true 1080i. Because as humans we merge the two fields together( for a CRT system. For LCD or PLasma then one would be looking at the quality of the scaler and de interlacer as these displays are progressive in operation so all interlace feeds have to be deinterlaced for display) . At any instant the 720P picture will have more but will have no changes for the next 1/60sec whereas there will be a total different set appearing from the next 1080i field . The ideal would be true 1080P60 but we may have to wait a little for that. The way things are changing though that may not be too long.

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Old May 4th, 2007, 05:18 AM   #7
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Also remember if you are considering the 1080i/p cameras in this range (Canon/Sony/HVX), NONE of them use Full HD chips. The canon uses the highest, with 1440x1080 3-CCD, the Sony with Diagonal 960x1080, and the HVX is below that (I forgot the number right now, might be 960x720 3-CCD). The 1080i HDV spec is recorded as 1440x1080 (as if the DVCPRO HD of the HVX). None give you a full 1080p recording Navtively, all have to use pixel shifting at some form or another.

Now, the JVC is FULL HD at 720P. It uses 3-CCD 1280x720 chipsets which means that no pixel shifting is ever taking place. Something to consider.

Also, interlaced stuff to me is just not worth dealing with. Start progressive, end progressive if possible.

Remember, even major studios are split on this issue. FOX, ABC, ESPN, and HBO (not 100% on HBO?) use 720P. In my opinion, their programming looks better.

Also consider that the JVC uses a Short GOP (6 for 24/25, 12 for 50/60) while the Canon and Sony use a 15-GOP which is much worse for dropouts and motion. The HVX does record Intra-Frame with its DVCPRO HD codec, but there is less resolution.

The numbers game is very interesting and it really comes down to what is best for you. Adam Wilt had a very good article in DV recently and basically said that any of these cameras offer enough resolution for what they are designed to do.

Honestly, focus a little more on features and form factors.

And yes, a true 1080P camera is obviously better than a 720P camera, it's just none of them in this range actually record "Full" 1080p. Sure, you will get a file that is 1980x1080, but processing occured, it is not Native. I can upress my ProHD footage, it wouldn't make it better.
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Old May 4th, 2007, 09:00 AM   #8
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720p will convert to 1080i better than 1080i will convert to 720p.

However, since you are in this branch of the foruim, I also strongly suggest that your camera decision should have nothing to do with the issues you have brought up (mic inputs, scanlock, 720/1080).

The JVC GY-HD series are larger, and have a pro based ergonomics and form factor that suits many people, but not others.

One of the major adjustments for people upgrading from smaller camcorders is that the lens has no autofocus. It has many configurable settings, but without many user features common on consumer oriented gear.

I'm not sure exactly how you plan to use the camera, but it's quite possible this isn't the right camera for you, judging from the questions you asked.
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Old May 4th, 2007, 03:55 PM   #9
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Thanks

Thanks for all the comments guys. Unfortunately, I am not able to try one of these cameras before I buy. There just aren't places to get them around town. But I appreciate what you have said about interlaced vs progressive. It's always one of the first things mentioned in the description, so I thought it was a make or breaker for the camera. I will now focus more on the features, and yes I do think auto focus would be a good idea, Sean.

Thanks again.

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Old May 4th, 2007, 04:53 PM   #10
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Philip,

If you are willing to lay out $4800 or so for an HD100, but then are considering the Sony A1, you are missing several other cameras that will have auto focus which I believe you stated you would like.

The HD100 is designed for people who are used to shooting with more traditional News and ENG cameras.

You should look at either the Sony V1 or the Canon XH A1 which are around $3500 - $3800 in price and produce very nice images.

I am not telling you to not get the HD100, I have one and love the image that it produces, but it is not for everyone.

Good Luck,

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Old May 5th, 2007, 03:54 AM   #11
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I ran into the resolution debate when I purchased some still gear a few months back. I could get a 10.1 megapixel model for cheap or an 8.2 megapixel model for more $$ but with a better interface. Guess which one I picked. The one that wouldn't drive me nuts when I'm trying to get work done with it.

HD is HD, and with easy cross-conversion between standards it's really about overall picture quality (i.e. overall sharpness, color rendition, dynamic range, noise) and having a camera that you can actually run instead of having it run you. Going through menus for common features is unacceptable. A lens that focuses by wire and feels laggy is unacceptable. Not being able to put it on your shoulder for proper handheld shooting is unacceptable. Having to spend a thousand bucks on a flash card that only shoots for 8 minutes in HD is un-friggin-acceptable. These considerations make JVC's ProHD cameras the only viable choice for budget HD acquisition as far as I'm concerned. If you don't consider any of these points to be showstoppers, try shooting for 8 hours a day every day with any of the other cameras in this price range and let me know when you've changed your mind.

To answer your other questions:

1) Scan matching (also called synchro-scan or clearscan) lets you sync the shutter speed of your camera with the scan rate of a CRT monitor so you don't see black bands moving through the picture. Definitely worth it if you shoot lots of interviews because you're definitely going to be shooting a guy in his office with his computer behind him one of these days. If you're shooting events or drama, eh, probably not. For drama if you're doing it "the right way" you're probably going to comp a new screen image in there anyway.

2) You can get an 1/8"-to-XLR adaptor, but I'd highly recommend actually getting a wireless system for your lav. Wireless audio really frees up your shooting, especially if you're going solo and don't have an assistant who can manage your cables for you. Also, since your transmitter would have an 1/8" input you could also hook up any audio source you want using an adaptor, like a PA feed or whatever, without having to run a cable to your shooting position. I use that feature alllll the time.
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