...with default zebra you see overexpose the shine in hair.with rgb zebra and neutral you get correct expose picture
Now, I understand.
I would first suspect the value of "over".
over = 255-conf.zebra_over;
"over" is compared to viewport pixels to signal overexposure. It use the same "over" for "Y" and "RGB".
if (conf.zebra_multichannel)
{
uu = (signed char)img_buf[v];
vv = (signed char)img_buf[v+2];
sel=0;
if (!((conf.zebra_mode == ZEBRA_MODE_ZEBRA_1 || conf.zebra_mode == ZEBRA_MODE_ZEBRA_2) && (y-x-timer)&f))
{
if (clip8(((yy<<12) + vv*5742 + 2048)>>12)>over) sel = 4; // R
if (clip8(((yy<<12) - uu*1410 - vv*2925 + 2048)>>12)>over) sel |= 2; // G
if (clip8(((yy<<12) + uu*7258 + 2048)>>12)>over) sel |= 1; // B
}
;
buf[s]=buf[s+1]=cls[sel];
buf[s+2]=buf[s+3]=cls[sel];
}
else if (((conf.zebra_mode == ZEBRA_MODE_ZEBRA_1 || conf.zebra_mode == ZEBRA_MODE_ZEBRA_2) && (y-x-timer)&f))
buf[s]=buf[s+1]=COLOR_TRANSPARENT;
else
buf[s]=buf[s+1]=(yy>over)?cl_over:(yy<conf.zebra_under)?cl_under:COLOR_TRANSPARENT;
if (buf[s] != COLOR_TRANSPARENT && !zebra_drawn)
zebra_drawn = 1;
Comparing "Y" values and "RGB" values with "over" don't seam to be equivalent and, may be, it's because the "Y" component don't have the same scale (16-240) than "RGB" components (0-255).
en.wikipedia.org YCbCr
Is it sound good?
yes, and its not only the diffrent range.
Maybe you can photograpgh the granger chart that is upload here,and look that no zebra blink in standard zebra.
http://farm6.static.flickr.com/5307/5673254230_96f2049213_b.jpgYou can see many light colors are white now, when you look at the jpg image.
now switch to rgb zebra and do same.image is correct exposure, all colors are here.best you use fast ev switch 1/6 EV chdk setting, so you can change ev fast.
when use mycolors neutral, diffrence is not so much.
it seem happen that Y + U + v in term convert to a color, get more than 256.Y only is below 256.so only the RGB zebra show correct.
you can see when photograph on granger chart too.pure red or green or blue colors, contain very low Y.
when you are in standard mode you can enhance ev lots until pure red , or green or blue colors do blink with zebra overexpose warning.
but when you look on image they are large overexpose.sure they are not change to white, but you get texture loss in real world when you use normal zebra.
