HELP! - HC1 Poor Red Color Accuracy

[Steve Mullen]

Originally Posted by John McManimie

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.

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.

The problem may be compounded by Sony's blue bias. And, the only reason I'm "in to" the issue of WHY is because it shouldn't be happening with HD -- except if you use Composite Out. Moreover, I've never seen it on an HD camcorder, except the HC1/A1. And, the word "overwhelms" is a real description of WHY.

So, yes it would be nice to have a few tips. Clearly, avoiding AWB is a good idea since it is never that accurate. Full Manual seems right. Using tinted "White" Balance card would seem another option. Try one of the "warming" cards.

[John McManimie]

Originally Posted by Steve Mullen

Moreover, I've never seen it on an HD camcorder, except the HC1/A1.

None of the others are CMOS based...

[Steve Mullen]

Originally Posted by John McManimie

None of the others are CMOS based...

Folks claim its not a problem with the HC3 which is CMOS.

[John McManimie]

A different sensor (already used in the DCR-DVD505)...

"...this sensor also uses a different CFA (Color Filter Array) layout which has six green photosites for each red and blue, hence increasing effective luminance sensitivity but decreasing chroma (color) sensitivity and resolution."

http://www.imaging-resource.com/NEWS/1138169251.html

[Steve Mullen]

Originally Posted by John McManimie[url

http://www.imaging-resource.com/NEWS/1138169251.html[/url]

Different yes -- but nothing in the description in any way explains why the color should be different.

But, it does raise several interesting questions:

1) The A1/HC1 CMOS already offers more HD video resolution than ANY HD camcorder -- so of what value is 1.4X more for HD video. (Companies keep thinking folks are going to take stills with their video camera, but every review of these attempts reports the efforts to be a failure. Flash is usually needed for a good still camera, for example. The A1 has no flash.)

2) Do we really want less chroma rez for HD video?

3) Will Sony keep the current CMOS in the A1 or switch to the new one? If the new chip really is better, as many claim, and they don't upgrade the A1, how will Sony deal with their "pro" camcorder recording lower quality video?

4) The DSP in the HC1 and A1 is very sophisticated. The A1 brochure makes a big deal of how it handles high-contrast scenes! No mention of what DSP is in the HC3.

5) At NAB could there be a new "A1" with the new CMOS and the current DSP?

[Christian de Godzinsky]

Hi,

I promised a while ago to set up some images takem with the HC1. FINALLY - here is where you can find them:

http://www.dextrel.net/photogallery/real.htm

ALL shots at normal factory defaults. The focussing was manual.

Reading comments here and elsewhere it seems that there IS noticeable variation from unit to unit in the color rendering in the HC1 (an also other CMOS models from Sony??). It seems also that this red color problem is fixed at least to a certain extent in the HC3. So Sony HAS done something about this malfuction - it has NOT gone unnoticed by their engineers.

Remember, these pics that I display are taken in the STILL image mode and you can still (pun intended) see the same problem in the color rendering as in the video modes. Still images are processed without any NTSC, PAL or MPG2 processing limitations - just postprocessed, matrixed and compacted in JPEG format.

The CMOS sensor produces three independent outputs in the RBG format. Digitally - since the AD converters are on-chip. Eiter the CMOS sensor in internally very nonlinear - or - the color post processing is inferior or not able to compensate (at least with this firmware version) for some shortcomings in the CMOS sensor.

Please also remember that there are many CMOS based professional quality cameras that produce fantastic color reality. So I would not blame this on the CMOS technology itself. It just happens to be the new kid in the block that takes the blame. Or then the sensor is really a flop and Sony is able to manage the output somehow with good DSP processing.

It is vell known that Sony cams produce cooler (more bluish) images than for example Canon. However, the color rendering on my other consumer Sony cam is like from another planet compared to the HC1. I probably should put up some additional pics...

I am fully aware that since TV broadcasting uses FM modulation there is a limit how great the modulation is allowed to be. Therefore both NTSC and PAL standards define distinct IRE (signal level) restrictions. There is a practical limit of the crominance signal since it is added as a carrier to the luminance signal. At high brighness (close to 100%) there is less room for a high amplitude color carrier. This is well understood. Eveyone agrees that HD has nothing to do with NTSC or PAL, as little as JPEG has to do with NTSC or PAL. And - as my experiments with STILL images shows, this problem with HC1 has nothing to do how video is encoded in NTSC or PAL - the problem is well before this signal processing !!!

Best regards,

Christian

[Laurence Kingston]

I just finished going through a bunch of footage looking for reds. As I look at them, they aren't perfect, but they are nowhere near as bad as what you posted. They are all full auto. I have some frame captures but no way to post them. If anyone can post them I'll send them to you. They're downsized so they are not big files.

[Steve Mullen]

Originally Posted by Christian de Godzinsky

The CMOS sensor produces three independent outputs in the RBG format. Digitally since the AD converters are on-chip. Eiter the CMOS sensor in internally very nonlinear - or - the color post processing is inferrior or not able to compensate (at least with this firmware version) for some shortcomings in the CMOS sensor.

Your pix dramatically show why my impression of the CMOS Sony's were that they produced pastel color -- the red has no intensity! It is saturated (rightmost chips) correctly, but the brightness is wrong.

And you are correct about how CMOS works. At NAB, I'll take printout's of your site to some Sony folks I know in the pro division. Fundamentally, now that you have documented the problem the question is can it be fixed by Sony service.

[Cooleye Hu]

I tried the similar thing as Christian did, and I got to agree HC1 does have a serious drawback for red color reproduction under certain situations. Bright red is definitely nonacceptable with HC1. Thanks the god that in reality we seldom has this situation.

SONY definitely realized this issue and maybe that is why HC3 uses differecnt CMOS. This also means most probably the cmos of HC1 is defective in the red reproduction... It is rather disappointing, and I hope SONY will have some software/firmware solution later, though chance are slim.

[Cooleye Hu]

Now I feel something strange, it seems that all the complaints are from HC1 users, how about A1 users? Do they have the same problem? Will black stretch solve this problem to some extends? I wish A1 users can provide some comments.

[Steve Mullen]

Originally Posted by Cooleye Hu

I wish A1 users can provide some comments.

I assume too the A1 has the same problem. And, it looks like there is no replacement. So how ARE A1 shooters handling it?

[Laurence Kingston]

Originally Posted by Steve Mullen

I assume too the A1 has the same problem. And, it looks like there is no replacement. So how ARE A1 shooters handling it?

Well I had to go through many hours of footage to find a frame or two with a bright enough red to cause a problem and then it's not all that bad. Nothing like as bad as those charts a few posts back. I will just keep shooting and ignore the problem for the most part. Yeah I will look for it every time I see red and check out the reds on any new camera I buy, but I really don't see it being enough of an issue to really bother me. The image quality of this camera still amazes me every time I see it.

[Paul Rickford]

I have been keeping an eye on this post while going through hours of footage taken on 3 different cams (a HC1 which I traded in for a A1 and a loaner A1 when my zoom packed up) and I can't see anything that serious with the reds - maybe a bit cool sometimes on auto white balance but manual or daylight setting WB no problem.
In fact i get a big smile on my face everytime I project this stuff, the overall colour knocks my socks off!
IMO the A1 even can be better for colour including Red in good light than my Z1, so even if a batch of chips where down on the red maybe a lot may be down to our own eyes?

[Steve Mullen]

Originally Posted by Paul Rickford

IMO the A1 even can be better for colour including Red in good light than my Z1, so even if a batch of chips where down on the red maybe a lot may be down to our own eyes?

If you look at the posted charts, you can hardly call the reds accurate. I don't think folks would be having these problems if the A1/HC1 reds were more accurate than a Z1.

However, excluding the red problem, it is entirely possible that the A1/HC1 have better looking greens because the Z1 tends to bluish greens. So I'm not doubting your observation.

[Paul Rickford]

Steve, i agree with you with the charts and if my cam was showing reds down like that i would be all over Sony but i'm just not seeing it on my footage at the moment either by good luck or maybe years of the old amber beer have given my eyes built in red warm balance!
I nearly did'nt post as I hate 'mines ok -yours is not' type posts but for once it's all working ok here.
Regards