DVX-100 internal ND's

[J. Lamar King IMPOSTOR]

Thanks for all the help you guy's gave me with my recent shoot with the DVX-100. It went great and we got everything we wanted. Awesome camera and we want to finish the docco with it. But;

 

While lining up the first shot of the day I noticed the tone of the sky was a deep steel blue in the monitor not like the rich blue it really was. I assumed it was due to not being able to see the monitor well even with a hood.

 

Also, after close scrutiny of the footage I noticed that the subjects shirt appeared to be a rust colored red in the first scene, a nice royal blue in the second and sort of a mixture of the two in the third! WTF

 

After an hour of twidling knobs trying to color correct the playback to get the shirts to match I concluded that the subject must have changed shirts during the day. Of course no one noticed this happen. A hunt through the footage revealed he indeed had "changed" shirts. Apparently he took off his shirt to remove an undershirt (it was cold in the morning) and when he put his shirt back on he turned it inside out. It was reversable!!

 

This didn't account for the odd shift in the color of the sky in the first scene. Which now knowing he had changed shirts, when correcting for the blue shirt he had on in the second scene the first scene was WAY off color. Looked like it was shot with an 85.

 

I modified and saved scene file 5 the night before and I know I had it set right when shooting because I named it 101. I didn't change anything but detail to -7 and pedestal 0. I used the factory preset 5600K color balance, I did not do auto or manual color balance at any time during the day and it was always set to 56K. The only time the camera was turned off was between scene 2 and 3.

 

On scene one at 11:30am, full sun, I used a .6 and a .9 Schnieder ND and the internal 1/64th ND to get a stop 4. Looks like it was shot through an 85.

 

On scene two at 2:00pm,shooting into a garage, subject lit by skylight and a Kino Flo to light the BG, I pulled the .9 ND and switched Out the internal ND to get a stop of 5.6 with just the .6 ND in. Color balance is perfect the subject and the area lit with the Daylight Kino are both perfect white light.

 

Scene three at 4:00pm, lower sun, I switched the internal 1/8th ND In and still with the .6 Schneider for a stop of 4.8. This scene is closer to scene two than one. The shirt seems to be blue but it looks a little off toward red. Could be the warmer light.

 

So now, looking at the First and Third scenes through a full and 1/2 CTB they immediately color correct to almost normal. Still some other shift in there.

 

Common thread here is the use of the internal ND filter. Are these known to have a color cast? Might have been the Schnieder, ND85? But I know I looked at it and it was a plain .9 ND.

 

Hmm...

[Mitch Gross]

The other common thread is that the sun was moving all day long. It's possible that the color temp. shifted during the course of the day, sometimes dramatically. And switching from daytime shadow to daytime sun can make for a huge shift in color temp. That's why balancing off a white or gray card can even out a lot of subtle shifts.

[J. Lamar King IMPOSTOR]

Yes, I suspect that could be it. That first and most orange setup was shot in almost mid-day light. I don't think it could have been that orange but it definately could have been something to do with the white balance of the camera.

 

It really looks like an 85B, I know that color when I see it. The .9ND might have been an 85ND. But I would sware it wasn't. I'm going to call the rental place to check but they may not be able to find it.

 

Do you feel it's better to white balance throughout the day? I didn't want to mess with it this first time because I wanted to work more like a film camera, that's what I'm used to.

[Guest Ultra Definition]

The outdoor color temperature changes during the day. There is however still one more factor that comes to play when working wit color monitor. Your brain too has auto white balance function. If you are in a room with 2.500K light, white paper looks white. The paper looks white also outdoors with 10.000K light. If you would light 1/2 of the paper with each of the lights and the rest of the room would be illuminated with 2.500K, the 10.000K would look blueish. With the same split light outdoors with 10.000K ambience, the 2.500K would look pinkish.

 

What does it mean? You can't have the same monitor setting indoors and outdoors, outdoors during different parts of the day, etc., and expect the monitor to show, or rather your eyes to see, true colors.

[Phil Rhodes]

Hi,

 

I always find it's a bit tricky to tell when it's worth re-balancing. Normally you'd try and do it at a point where you know that shots won't be cut back to back, but at some point you have to make a call and say that it's going to be so far out it's unusable, and rebalance.

 

Or, you can hit auto. It'll tend to make the shot look a bit flat and dull, and possibly make bad decisions in mixed temps, but the one thing it will do is consistently track changing colour temperatures over a very long period.

 

Phil

[J. Lamar King IMPOSTOR]

Thanks Phil,

 

I'm now all but certain that the ND .9 was actually an 85ND9 or some kind of Coral and ND. After loading the footage into an editing program and color correcting, the second and third scenes were normal. The third scene was a little warm due to late day light.

 

The first scene is so screwed looking, everything is orange/magenta. I found a shot I slated and I was wearing a dark blue ball cap and it appeared as a maroon color in the uncorrected footage. Thankfully it corrects out easily. I'll just have to watch that camera closer next time to make sure and get the rental company to look through their ND's Monday to see if they can find the filter for positive proof.

[Mitch Gross]

Just a good on-set work note. I never trust the pouch label for any filter. I always check the filter itself to make sure that it is the correct item. I've seen too many people drop filters into the wrong pouch when in a hurry.

[J. Lamar King IMPOSTOR]

Just thought I should let you guys know that I, or rather Kirk Miles at GEAR Rental in Austin finally tracked down the cause of this strange color shift problem. It was a couple of bad, glass B+W Schneider ND's. They apparently were not manufactured in as "tight a tolerence" in color neutrality as they should have been. I wonder if anyone else has experienced this phenomenon with these filters, I've never had any problems with them before. Kudos to Kirk and GEAR for staying on top of this problem until it got solved. Schneider has replaced the filters with clean glass.

 

Here is a screen cap showing the odd coloration, this shirt is actually a very rich blue! ND .6 & .9

 

 

Again, shirt way off skin tones whacked, ND .6 & .9

 

 

Here is the culprit caught in the act, look at the color tint in the sky, ND .6