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JVC GY-HM 70/100/150 Series Camera Systems
GY-HM70, HM100, HM150 recording AVCHD MP4 & QuickTime .MOV to SDHC cards.


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Old July 11th, 2009, 02:24 AM   #16
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Originally Posted by Amir Jaffar View Post
Hey Robert..
Guys shooting FICTION will always be obsessed with the film look. You can't help that. You just get conditioned that way having grown up admiring, learning and seeing movies - movies that were shot on film. They'd rather die than see their film looking like an afternoon soap.. YUK! (which btw are shot on high end cameras too) Haha.
I think you might be surprised what "soaps" look like when shot in HD in the USA. Likewise, watch some Japanese and Korean "costume" drama shot in 1080i60. I've watched Indian soaps and the cameras may have been expensive but the production values were just plain horrible. Which comes back to lighting and shooting style.

You can, of course shoot 720p60 and drop into a 720p24 Timeline and get "real" 24p to go to DVD/BD. The shutter speed will be too slightly too fast, but 24fps sampling judder will be there -- plus the 2-3 motion judder needed for 720p24 to go to a 60Hz flat-screen. You can even get fancy and, in post, add a bit of motion blur if you want.

This is how 720p60 is being used with the Panasonic GH1.
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Old July 13th, 2009, 06:22 AM   #17
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Hey Steve,
that tip for the timeline fix sounds great.. can't wait to try it and will let you know how it goes. Thanks.

And Indian soaps were nowhere in the reckoning in my post. These guys still shoot on Digibeta and production values as you said, do leave a lot to be desired. However have not really been able to dig any HD samples of current U.S. soaps on the net, nor the costume dramas you mentioned. The only ones I managed to view were current clips of some American soaps that had video suds all over them ;-)

Though will keep looking and get back to you. (a link or two might be useful, since you've really aroused my curiosity about soaps shot on HD)

Thanks and cheers
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Old July 13th, 2009, 10:18 AM   #18
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Originally Posted by Amir Jaffar View Post

Though will keep looking and get back to you. (a link or two might be useful, since you've really aroused my curiosity about soaps shot on HD)

Thanks and cheers
In the USA some cable networks have Korean TV which includes Japan and India programming. The HD stuff I saw when I lived in Asia. HD has been in Tokyo since about `86. All 1080i60. SD was all DigiBeta. No film except for stuff shot before the `80's. No interest in 24fps for anything.

Not sure if any programming is 720p60 or there is an HD service that is anything other than 1080i60.

Interestingly, much SD drama shot on-location with a very economical style. One camera with one run-through on person A and another run-through on person B. Then simple cuts between the two takes. Zoom used between takes on a camera to get CU or 2-shot or "group" shot.

HD used differently. Shoot one run-though of "group" and then occasional CU. Much like American TV in the 50's. Use HD like a "scope" movie.
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Old July 13th, 2009, 10:39 AM   #19
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Steve, returning to issue of motion blur, when I was shooting 720/60p I liked sometimes more the effect of shutter speed 1/100 vs. 1/120. At least to my eye the ski sequences looked more pleasing. Any comments? (btw we used HVX200, not HM100 then)
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Old July 18th, 2009, 10:49 PM   #20
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Have you watched your 24p footage on a 120hz HDTV?

Just to stir the pot a little......

If you really don't like the 24p judder.. get a better monitor or HDTV.. No I'm not being a jerk, I'm just acting like one on the internet. :)

I watched some footage on the newer Sony 32" XBR9 1080p 120 hz LCD HDTV, Freaking AWSOME! The 24p came out MUCH smother (all motion smoothing was off by the way) and was very film-like (as in the movie theater experience showing 24p film) In another couple years all the mid priced HDTV's will be 120hz. It has to do with that 24 doesn't play nice with the standard 60 hz HDTV's. Why is for someone else to chime in. I am told it's because of cycle rate. The 100 hz HDTV's often have motion smoothing systems than the standard 60 hz HDTV to give DVD's and broadcast 24p source material the film motion again, but I'm not impressed.. spend $200 more and get a 120hz name brand HDTV. The better HDTV's are now claiming 240 hz... Does it look any better? Maybe on a bigger HDTV... I didn't see a world of difference in the 40" range.
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Old July 18th, 2009, 11:02 PM   #21
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side note about DirecTV and Dish. Apparently DirecTV and Dish have been dropping their broadcast resolutions to combat macro blocking. Both are compressed to near DVD bandwidth and there was too much objectionable artifacts. Reports of DirecTV being dropping stations to 1280x1080i resolution and Dish down to 1440x1080i. The 720p stations (ABC & Fox) don't seem to be doing that. NBC & CBS stations are 1080i.

Here is an interesting link if you want to read more about multicasting and further squeezing of signal. Could explain why I'm not impressed with my DirecTV, and prefer to get DVD's.

Broadcasters' HD Squeeze Play - 2009-07-02 15:00:00 EDT | Broadcasting & Cable
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Old July 24th, 2009, 03:42 AM   #22
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Originally Posted by Robert Rogoz View Post
Amir, I just don't see why do you insist on shooting 1080? 1080 resolution with these cameras (as well as many others) is achieved via pixel shift. However they record 720 native. I filmed ski and mtn bike footage and the best results were achieved (mostly with HVX200, 2 days with HM100) in 720/60p. (not in 1080/30 or 24) I also shot some footage with GY-HM100 and for faster motion I used 480/60p option, as the matter of fact the footage looked better then 720/30 or 720/24p in regard of motion blur.
Because even with pixel shift, 1080 still looks BETTER in most cases. I have the JVC GY-HM100 and have done extensive comparison shots between the exact same scene shot in both 1080 and 720. In shots that involve a lot of fine detail (e.g. leaves of trees in the distance), the 1080 footage (either progressive or interlaced) is definitely sharper and clearer, providing that the footage is filmed under bright light (and, I assume, providing there is a reasonable amount of each of the primary colours (red, green and blue) in the shot). Also the overall look of the shot is less "soft" in 1080 than in 720.

There is nothing "evil" about pixel shifting if the end result looks good. I can honestly say that this camera comes close to Blu-ray quality for many scenes.

I will only ever be using 720p60 (or 720p50) if I have slow-motion scenes that I require.
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Old July 24th, 2009, 10:29 AM   #23
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Originally Posted by Anthony Shera View Post
Because even with pixel shift, 1080 still looks BETTER in most cases.
Actually it's more accurate to say that 1080 still looks better *because* of pixel shift, not despite it. Pixel shift is a good thing; it's something you want, not something to be worried about. With only a couple of notable exceptions, just about every three-chip sensor block ever designed has had some form of pixel offset technology built into it.
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Old July 24th, 2009, 11:39 AM   #24
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Pixel shifting has always been a trade off... lower inherit resolution but gaining light sensitivity and often dynamic range. Sony DV-Cams for instance where always very pixel shifted, but they also where very sensitive in low light even before running gain up. The problem is with more agressive pixel shifting it creates more and more weird artifacts, especially in a progressive format. So it's a balancing act. Zero pixel shift means a better image especially with progressive when recording subjects with straight lines, but less sensitive in low light. Pixel shift in various amounts to increase light sensitivity withoug going to a larger chip (getting away with a 1/4 or 1/3 chip instead of 1/2 or larger) at the expense of various degrees of artifacts depending upon the factory settings.

I personally prefer zero pixel shifting. My JVC HD110 is more than fine with zero gain for daylight situations, and for indoor i'm using soft boxes and fresnel lights so i don't see a problem. You can get the uprezzing of 720p to 1080p in post as well, but you are in control of the scene by scene uprezeing with keyframes. More of a hassel, but I'm fairly certain the results will be better. However these new JVC HM class 1080p does look good, though I haven't used one yet. So I expect JVC has hit a decent balance with their 1080p pixel shifting.

Similar note: Exceptions to what I said.. The Panasonic HVX200 DOES looke appreciable better at 1080p/i than their 720p settings. Apparently when shooting 1080p the chips are 540x960, pixel shifted, then uprezed.... the 720p uses even less pixels and are just uprezed. Not sure on that, but that's what I hear and I tend to believe it from the video testing I saw. Still has great color and pretty good low light capabilites... Again, it's all about trade offs.
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Old July 24th, 2009, 04:17 PM   #25
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Originally Posted by Alex Humphrey View Post
Pixel shifting has always been a trade off... lower inherit resolution but gaining light sensitivity and often dynamic range...
This has been the trade-off with CCDs. With CMOS there's no problem to getting chips that have the same number of elements as the recorded resolution AND are very sensitive. A 2M pixel CMOS is trivial while a 2M pixel CCD is very hard as the sampling rate drives-up power consumption and HEAT. And, the smaller the chip the greater the heat issue becomes. With CCDs, 960x540 to 1280x720 is, for a small chip, just about the limit.

Thus, to record HD, pixel-shifting of some type is necessary if you use small CCDs. (And, "yes" CMOS chips have their own problems but multi-channel read-out is helping.)

Here's the rub.

Chris is correct that pixel-shifting has almost always been used. But, for a VERY different reason than it is used for now. To record SD, a chip ideally should be 720x486 for NTSC or 720x576 for PAL. These are EZ chips to build.

Let's look at a PAL chip. At 576-rows it means these CCDs already generate 540-lines of video. To obtain a wide-screen picture WITH THE SAME NUMBER OF HORIZONTAL PIXELS PER INCH on the chip, the chip needs 960 pixels. (Other cameras simply squeezed the wide image into the 720-pixels.)

So companies have been making 960x540 chips for years for their SD cameras that could switch between 4:3 and 16:9. This is why I call them SD chips.

When in 4:3 mode, the design could simply use 720 of the 960, or by off-setting the green CCD, it could SUPER-SAMPLE the image which adds about 15% (nowhere near 50%) more resolution. It's like whip-cream on a Sundae. Nice, but NOT necessary! (My memory is hazy on whether this was really done. I do know that even non-switching camcorders used pixel-shift to SUPER-SAMPLE 720x480 chips to add a bit of "extra" detail.

When you know who wanted to build a low-cost HD camera it realized it could use the "PAL" CCD design and not have to invest in a new HD chip -- as did Sony and JVC. It tried to market this chip without specifying its pixel count. When caught, by me, they switched to the advantages of light sensitivity and dynamic range. Which, to some degree is true.

Of course, SD is a long way from HD. So they used both H and V offset. Since many reviewers were content to use the "increases resolution by up to 50%" concept/claim they thought the camera could capture 1440x810 which is all that's needed for a solid 1280x720 recording. (I guess some thought pixel-shifting could somehow get 200% more resolution so as to record 1920x1080. Even though that's not how the camera worked. If I remember, the image was up-scaled.)

Of course, measurements -- especially NON-static measues -- showed the real increase was about 15% on each axis placing the recorded resolution for 720p far lower than needed to be a true HD camera. Worse, the combination of fundamental and aliasing made it's actual recorded resolution, according to the BBC, impossible to measure.

Of course, the eyes of those who bought these cameras saw none of this. Finally, when the Sony EX shipped and folks saw what 1920x1080 chips could yield, many began to admit that "yes, indeed, the 960x540 generated recordings were a bit soft. Of course they were! You cannot generate REAL information much beyond that which you capture.

PS 1: I'm not saying that the 960x540 generated recordings were not pleasing to many.

PS 2: The ACTIVE process used by JVC on the HM700 is NOT the same as the passive process used in the past. An active process as used by JVC, and Sony on the FX1, really can obtain a cleaner (and with the FX1) a more detailed image. It's takes a DSP chip to do this.

If anyone's interested I have JVC's slides on how their active process eliminates artifacts.
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Old July 24th, 2009, 05:07 PM   #26
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Originally Posted by Steve Mullen View Post
If anyone's interested I have JVC's slides on how their active process eliminates artifacts.
Sure, it is pretty interesting.
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Old July 24th, 2009, 09:05 PM   #27
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Sure, it is pretty interesting.
I second that. Also I'm very interested in what JVC means when they say their HM cameras have a new Dynamic Digital Signal Processor in which "processing is performed on the full progressive 1920 x 1080 signal, regardless of the camcorder’s settings, ensuring the highest picture quality in any shooting mode."

The chips of the HM cameras are supposed to be 720p native, so I can't quite get my head around the 1080p DDSP thing.
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Old July 25th, 2009, 09:02 PM   #28
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The chips of the HM cameras are supposed to be 720p native, so I can't quite get my head around the 1080p DDSP thing.
While I look for my slides: It seems then the 1280x720 chips are always pixel-shifted to obtain 1920x1080. JVC is assuming that a 50% increase in resolution is possible. I would expect dynamic (moving) measurement to show more like a 15% increase on both axes.

All signal processing is performed on the 1920x1080 signal. Then the signal is sent to the encoder as 1920x1080 OR converted to 1280x720.

Here's where it gets really interesting.

For a 720p recording, pixel-shifting SUPER-SAMPLES the image to obtain "extra" information. In other words, more detail than can be obtained were pixel-shifting not used. The information each axis is a "bonus."

Is this bonus detail be recorded? No. But, if we compare the recorded signal from two designs: the one that uses SUPER-SAMPLING will have stronger high-frequency information (fine detail) than one that doesn't. So pixel shifting makes a "better" recording at 720p from 720p chips.

By a BETTER I mean more fine detail.

However, pixel-shifting introduces artifacts. It obtains extra information but it introduces errors. Something not ever talked about. :)

JVC's design on the HM700 reduces these errors making the extra detail have less errors. I suspect it does not actually increase measured rez. But, to the eye its pix will be cleaner which is more import than rez. itself.
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Old July 25th, 2009, 11:37 PM   #29
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Is this bonus detail be recorded? No. But, if we compare the recorded signal from two designs: the one that uses SUPER-SAMPLING will have stronger high-frequency information (fine detail) than one that doesn't. So pixel shifting makes a "better" recording at 720p from 720p chips.
By a BETTER I mean more fine detail.
However, pixel-shifting introduces artifacts. It obtains extra information but it introduces errors. Something not ever talked about. :)
Now, if you record shots with minimum movement 1080 looks "better" or cleaner, but I think that's exactly where things fall apart with fast moving action? So my question is: in this specific type of shooting is 720/60p better for smoothest possible video?
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Old July 26th, 2009, 05:38 PM   #30
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Now, if you record shots with minimum movement 1080 looks "better" or cleaner, but I think that's exactly where things fall apart with fast moving action? So my question is: in this specific type of shooting is 720/60p better for smoothest possible video?
I wouldn't say 1080 falls apart, since that sounds like a codec problem.

1080i is interlaced which means either your eye or the deinterlacer in your HDTV must deal with 2 half vertical rez images to get one full vertical rez images. The fields arrive at 60Hz and the frames at 30Hz. Although we live with this, it is not ideal. Moreover, with CRTs the interlace didn't need to be DEinterlaced. The CRT was an interlaced display -- out eyes did the integration.

With flat-panels -- electronics must convert 60i to 60p. With motion this can NEVER be done correctly.

With 60p, we get wonderful smooth motion with no interlace artifacts. HDTVs do not have to deinterlace. Everything looks great.

PS: However, the vast majority of LCD monitors only show 330- to about 660-lines of vertical rez when there is motion. So unless you buy a Samsung LED LCD monitor you will have low rez images even with 60p. Only plasma and DLP deliver, with 60p, a full 1000-lines of vertical rez.

So when people talk about camcorder video quality -- one needs to remember that since most folks buy an LCD HDTV, so what they "see" may be funk from their monitor. Unless one has a Kuro or Panasonic plasma, or a DLP, I don't trust what they see.

This becomes even more of a factor with 24p. Here, even the best Panasonic plasmas screw-up. Only the Kuro -- no longer being made -- can correctly show 24p carried in 60i OR 24p from a BD.
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