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Sony HVR-A1 and HDR-HC Series
Sony's latest single-CMOS additions to their HDV camcorder line.


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Old April 2nd, 2006, 03:58 AM   #46
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I thought some people with A1s had this problem too?
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Old April 2nd, 2006, 05:10 AM   #47
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UPDATED EXPLANATION

All NTSC video cameras have circuitry that keeps chroma levels from exceeding acceptable limits. (Red must be limited otherwise, when a television separates luma from chroma, the red signal will contaminate the luma signal. The result is "cross color" artifacts that appear as "squiggles" on red objects.)

A three-chip camera can monitor Red, Green, and Blue signals and precisely control them before they are converted to luminance (Y) plus red (YR) and blue (YB) color difference signals.

A single-chip camcorder can monitor and alter only the Red (YR) and Blue (YB) color difference signals. If there is an intense red or orange object in a scene, the Red difference signal (YR) must be limited. This can cause the red/orange object to become "pale" or pinkish because the Blue difference signal is less limited. Thus red is diluted with blue. (Because blue naturally has less intensity than red, it less likely to shift to magenta.)

An HD camcorder should not need to limit chroma, but the HC1 and A1 do exhibit a similar problem with both deep and bright reds. To help reduce this problem, be sure to avoid using AWB.
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Old April 2nd, 2006, 09:30 AM   #48
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Thanks for that Steve.
I'm assuming that PAL cams work the same way? i.e. that this isn't an NTSC only problem? I've read reports from people with PAL cams complaining about the 'red' problem too.

Alex - yes i've read about people saying the same thing on A1s too so i don't *think* it's anything to do with differences between A1 and HC1.
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Old April 2nd, 2006, 02:11 PM   #49
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This is just my opinion, but I believe that, ultimately, the "why" doesn't really matter if we don't have the ability to change it. All we can do is work within the limitations of the equipment we have.

I would like to think that people would do research BEFORE spending a couple thousand dollars or more on a camera, yet an amazing number of people who make substantial purchases (by my feeble financial standards) don't know the capabilities or limitations of their equipment until AFTER they buy. Early adopters should expect to run this risk, but others? I can't really blame Sony or any other manufacturer for any camera that has been out for a while which has limitations I could be aware of before making the purchase.

If the HDR-HC1 didn't provide repeatable color results under repeated conditions (it does) then I would see it as a problem. Otherwise, it requires some tweaking (as does every camera --- no camera is perfect).

I figure that I can throw an ExpoDisc lens cap on it (or the "three-coffee-filter" DIY model) for speed or use a REAL white balance card and accept it as it is. There really isn't anything else that can be done with this "problem", is there?
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Old April 2nd, 2006, 03:45 PM   #50
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Well, for me personally, of course I've done research before buying. It seems that no everyone with a HC1/A1 has a red problem, which I'm curious to know why. I guess I'm also hoping to get one that doesn't have the problem, and if it does, I know there are some ways to deal with it to some extent. That, and I don't feel that the red misrepresentation is too horrible anyways, just annoying.
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Old April 2nd, 2006, 09:15 PM   #51
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Quote:
Originally Posted by John McManimie
I would like to think that people would do research BEFORE spending a couple thousand dollars or more on a camera, yet an amazing number of people who make substantial purchases (by my feeble financial standards) don't know the capabilities or limitations of their equipment until AFTER they buy. Early adopters should expect to run this risk, but others? I can't really blame Sony or any other manufacturer for any camera that has been out for a while which has limitations I could be aware of before making the purchase.
Normally I would agree. But this is a much more subtle issue. I didn't catch it. I only noticed the colors looked a bit "pastel." But, I'm used to Sony cameras always being too blue for my taste. (Which is why I love my JVC HDV.)

The fact that it's subtle means it has taken a long time to be reported. So folks would not have seen negative reports if they had looked.

But, subtle doesn't mean it's not very real. For a decade I wouldn't buy JVC camcorders because they had orangish reds -- not true reds. To me very obvious. But, I bought Sony camcorders even though very bright reds went pink.

What's different now is that HD should remove all these problems. They are not present with any other HD camcorder. So, Sony is responsible for not getting this problem fixed before releasing the HC1/A1. And, it can be a deal breaker for some.

By the way -- in the late 50's, no saturated reds were allowed on set. When red was required, brownish-red was used. That prevented the "cross color" arifacts. This has been an NTSC -- and likely PAL -- issue from day 1.
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Old April 2nd, 2006, 11:52 PM   #52
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Just curious, are the people having problems with the reds noticing this problem in SD mode, HDV mode or both?
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Old April 3rd, 2006, 06:33 AM   #53
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AFTER MORE RESEARCH ON NTSC--I'VE UPDATED MY UNDERSTANDING:

In the NTSC system, the distinction between color tones is called hue and is carried by the phase of a chrominance component. (Hue is distinct from color saturation and color intensity.)

Saturation is the degree to which a color is different than white. For example, white, light pink, pink, or red.) The amplitude of a chrominance component carries saturation.
Whether a red is a “dark red” or a “bright red” is determined by the amplitude of the luminance signal—not a chrominance component.

The “I” (orange-cyan) and “Q” (green-magenta) components—plus the luma element—are mixed to generate an NTSC signal. In the process, it is possible for the amplitude of a chroma component (representing color saturation) to add with that of the luma component (representing color brightness) and create an illegal signal. Therefore, chroma amplitude (saturation) must be limited by the camera’s DSP. If the chroma amplitude is over-limited, a color will be desaturated. For example, bright "red" is will become "pink."

Analog SD “component-color” (BetaSP) plus digital SD (DV) and HD formats do not mix chroma and luma together and thus should not suffer from chroma saturation problems. Nevertheless, some single-chip, digital camcorders do have a problem with saturated colors.
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Last edited by Steve Mullen; April 3rd, 2006 at 11:27 PM.
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Old April 3rd, 2006, 10:56 AM   #54
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My last posting on this red issue:

As luck would have it, there was a bright red car parked right outside of my apartment. I shot footage of the car on auto, and with about 10 different tweaks with the A1. 9 of those tweaks were abominable. 1 had a "acceptable" (not great) reds.

I shot the same footage with my PDX10 on full auto, and outdoor white balance modes. Both had perfect reds.

I'm too lazy to log, capture and post that comparison online, but needless to say, I'm p**sed. I have funding for a DOC that I'm shooting mid may to mid june that I need to have HD for, and this seemed like the only camera that fit the bill. I'm going to have to bite the bullet and keep it for the duration of the movie and then resell. This is not an acceptable problem to keep having.
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Old April 3rd, 2006, 11:45 AM   #55
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Try white balancing to a pale blue or pale green card.
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Old April 3rd, 2006, 12:40 PM   #56
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Steve you are absolutely RIGHT!

I have recently bought the HC1, and I checked the red representation right away.I did not find anything wrong with red untill I read your post. Then I did a test to shoot the BRIGHT red, I just took some shots on a shining red led of my optical mouse, and find the brightest part of the red LED looks pinkish! So HC1 does have this problem although I have not had this situation in my regular usage.

Well basically I could accept this because I will seldom have the chance to shoot a red light. I am just curious that why you think HD should not have this problem? From what you described, it should be exsiting for all one chip machines, isn't it?
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Old April 3rd, 2006, 06:00 PM   #57
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I purchased my HC-1 just before Christmas. Using it during the Holidays, the colored lights and presents - including Red - looked fine. I had studied all the reports on this forum from the early adopters before I purchased it. Nobody mentioned the red color problem until this last month. I've used the HC-1 in wintery Minnesota and on a Cruise in the Carribean, not much red, and everything looked great. Even the sunsets look good, if your really study them they may be very, very slightly pink, but not noticeably so. However,the other day I shot a red airplane, outside in late morning filtered sunlight. The red is NOTICEABLY PINK. I did NOT have a UV filter on that day, but always did in the past. Some one sugested that maybe the UV filter helps? Has anyone experimented more with this?
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Old April 3rd, 2006, 06:08 PM   #58
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Quote:
Originally Posted by Cooleye Hu
I am just curious that why you think HD should not have this problem? From what you described, it should be exsiting for all one chip machines, isn't it?
NTSC mixes chroma and luma while HD does not -- unless you output NTSC. So I'm assuming this issue should not arise. But:

1) There must be a limit to the saturation value so it could still occur -- so you ask a good question.

2) The is another thing in common between the HC1/A1 and most NTSC camcorders -- they use Bayer filters. Which would mean it makes no difference whether a CCD or CMOS or NTSC or HD is used. Interestingly, the JVC HDV doesn't have this problem and doesn't use a Bayer filter. But, the HC3 -- one assumes -- does, and it doesn't have the problem. So I think #2 is not likely.

Now here's the big puzzle. Why does bright red not simply go up to a certain level of red and stay there? How does "red" go from pink to rose to red and then jump back to pink. It's like the signal goes up to the max red and starts over at pink!

I've got to think about this.

DAVE: "1 had a "acceptable" (not great) reds." What was the tweek?
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Old April 4th, 2006, 02:58 PM   #59
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There has been considerable discussion on the web with regard to various CMOS based digital cameras having issues with reds. At one point I stumbled onto some "astrophotography" sites where people complained about poor reds from digital cameras, especially those that are CMOS based. The conclusion is that the greater the intensity of the red, the more it overwhelms the ability of the sensors to discriminate accurate color. I guess I figured that it was just the way CMOS sensors currently behave and that I just have to accept it if I wanted the HDR-HC1.

If a subject is predominantly red, some digital cameras using auto white balance will view the subject as having a "warm" color cast and then compensate and end up creating a blue color cast. Some digital cameras are worse than others. For these, a manual white balance solves (most of) the issues.

It is obvious that the problem is real and I won’t debate that. However, it is also obvious that there is nothing we can do to change the camera (outside of a currently non-existent firmware upgrade that may or may not do anything); it is what it is.

I remain skeptical of anecdotal evidence. Not everyone conducts tests in the same manner or accurately (different intensities of red from different sources, different camera settings, filters or no filters, different light sources, different altitudes affecting UV, different materials used for manual white balance such as printer paper, etc).

That said, I do think there is a high amount of blue relative to the red (a Sony trademark?), but it still seems that a manual WB should solve (most of) this.

What we really need (and by we, I mean someone else) :-) is to move on to creating practical methods for preventing and mitigating the “reds” issue.



Test to determine under which conditions the problem occurs (so we can avoid them or better prepare):

- Is the effect the same when shooting red lights as opposed to other red objects?

- Does it occur more often under one type of light than another?

- Does exposure have any effect?


Identify “fixes”

- Perhaps more or less light

- Different light source?

- UV filters?

- Enhancing filters?

- Manual white balance? Using a real neutral balance card as opposed to random objects?


Identify post processes to minimize the effect.

- Color correction, color matching


... or maybe we just have to live with it?
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Old April 4th, 2006, 04:04 PM   #60
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About red light... isn't light a serie of on/off flickering in the speed of the Hertzrate you have in your country? In US that would be 60 per second and Europe it's 50 per second. I am just curious and it might have something to do with the problem.

I tried to screw my UV-filter on and off. If the colour was non-reflective red it seemed to keep the red slightly better with UV-filter. But it was hardly noticable. When I looked at some red with reflective surface it lost some of the red colour.

Can anyone who has the problem with red take some pictures of objects that are common e g a Coke-bottle should be fairly similar or red paper binder. It would be nice to see a variation of red objects and different surfaces.
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