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-   -   No A/B White Balance on PD150? (https://www.dvinfo.net/forum/sony-vx2100-pd170-pdx10-companion/12701-no-b-white-balance-pd150.html)

Lucas Hall July 31st, 2003 08:23 PM

No A/B White Balance on PD150?
 
I come from the full-sized camera JVC GYDV500 and I recall there's a switch A/B for white balance in which I store the outside WB on "A" and inside WB on "B". That is convenient for me when I need to run inside and outside constantly. I couldn't find something like that on PD150. How do you folks get this done or you just manual WB every time?

Thanks in advance,
Lucas

Mike Rehmus July 31st, 2003 11:10 PM

There are a few things lacking on the 150 and externally switched presets like that are one of them.

You could try shifting the WB in the Custom preset menu and see if that would get you far enough. Clumsy though. Page 56 in the manual

I actually find the auto white balance to be very good except in unusual lighing conditons like stages.

Lucas Hall August 1st, 2003 06:27 AM

Mike,
Thanks for the reply. How about the situation where the bride walks in from a door behind her with the bright background? What should be on auto and what should be on manual or should I just leave everything on auto and press the BACK LIGHT button?

Thanks,
Lucas

Mike Rehmus August 1st, 2003 07:41 AM

As you know, the PD150 doesn't handle nearly as fast as any of the 'big' cameras. So it poses a bit of a quandry.

As for white balance, you have no choice but to leave it on auto.

Back light is rarely accurate in my experience. It simply ups the exposure by a fixed amount. And auto cannot handle the situation either. Unfortunately, in this situation, manual aperature is the only answer and as we know, that steps the exposure in full 1/2 stop increments which is really noticable so if you are taping her walking FROM the bright to dark area, the change is really noticable.

If, on the other hand, you are taping her as she walks through the door starting at that point, then you can set the camera for the interior exposure and let the background blow out.

If I know this ahead of time, I'll set the camera and properly expose for the background through the door and take a 10 second clip. Then I'll take the footage of her passing through the door and lumikey that, replacing the blown out background with that properly exposed background. One can do this with windows and similar situations and it works fairly well.

Lucas Hall August 1st, 2003 08:31 AM

<<<-- Originally posted by Mike Rehmus :
If I know this ahead of time, I'll set the camera and properly expose for the background through the door and take a 10 second clip. Then I'll take the footage of her passing through the door and lumikey that, replacing the blown out background with that properly exposed background. -->>>

This is an excellent idea. I often arrive to location an hour before the guests arriving, so I should have enough time to do shoot the background alone with proper exposure. But how do I "lumikey" that, replacing the blown out bg with the properly exposed bg? I thought I'd need something solid behind her like a blue screen in order to take her out and put her in another background, no? I can't imagine putting a blue screen in a wedding ceremony, though :)

I'm use Premiere 6.5 with Storm 2. I also have After Effects.

Please advise,
Thanks,
Lucas

Mike Rehmus August 1st, 2003 10:23 AM

It's not a chromakey (making an automatic mask decison based on color. The decision is based on brightness.

Like chromakey, a lumakey is performed in the editing system. You might have to build a mask for the bride's dress if, around the edges, it gets as bright as the outdoor scene. But you don't have to do a complete lumikey for this to work. My editing system has the ability to set a range for the lumikey. So I cap the bright to somewhere below the bride's dress so it doesn't get touched.

Mind you this isn't perfect but a door entry is usually fairly quick so the work you have to perform is not too much and any less-than-perfect results are:
1. better than the untouched footage
2. over so quickly that usually only videographers will notice anything anyway.


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