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Sony TRV950 / PDX10 Companion
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Old July 20th, 2004, 09:24 PM   #1
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Another Noob question on Colour

These 2 shots were both shot on the same day about 2 hours apart.
The first one at 8am the second at 10am.
http://home.iprimus.com.au/tappings/IanF-Yellayuk.jpg
http://home.iprimus.com.au/tappings/IanF-Blueright.jpg
I manual white balance every half hour.
I have no filters on at the moment.
I can not remember what I had custom presets on, maybe this is my issue.
This was a bit of an odd day because half the time my shots were turning out really nice the other half I didn't like.
As you can see both are over exposed, however I do not have an issue with the 2nd one.
The first frame shows the white water having a yellow tinge which makes the over exposed part stand out so much, I can't stand this look and makes the shot unusable in my book.
The question is I guess how can I make the white water look purely white all the time so I never get this contrast in over exposed spots. I thought manual white balance would fix this, it hasnt.
I guess the ideal solution is to not over expose the pictures, however this is not always possible, with the high contrast of the ocean, the face of the wave and rider becomes much too dark.
Also another question I have, I set zebra on 100, these zebra patterns show up nearly all of the time on the white water part of the wave, however once seen on TV only some of the shots look over-exposed. I normally stop the exposure down so I can not see the zebra lines but the picture always becomes too dark.
Any tips at all would help, thanks.
You can be as brutal as you like with your answers, I'm only 17 so I'm new to this game and need some help.
So far you have all been very helpful in this forum.
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Old July 20th, 2004, 11:30 PM   #2
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> I guess the ideal solution is to not over expose the pictures,
> however this is not always possible, with the high contrast of
> the ocean, the face of the wave and rider becomes much too
> Dark.

Ok. I'm not the expert but here are some ideas: Contrast is something you will always want to keep under control. The best whay is to control it *before* it get's into the camera and recorded to tape, because given the limited lattitude of most DV cameras and the limited bandwidth of the DV codec, there is only so much you can do in post to fix it, especially with the highlights.

So the first thing you can try is to get some light, using reflective surfaces, onto the areas of the image which are too dark. You can buy some relatively inexpensive portable surfaces that can help you with this, you will need people to hold and point these surfaces in the right direction, of course. This is what is generally done, however in your case, because of the large area in question and the way it's moving all the time, it is most likely useless to try to control contrast in this way.

It might help to get the surfer to use a board with a white top surface, especially when his face is down near the board, which is when you will need the most help with his face.

The other thing you can do is use the custom preset menu to set the AE point down so that you have a minimum of overexposure. It doesn't matter if you slightly underexpose parts of the image. Of course, with all that light in your eyes you will have a feeling that you are going too dark when viewing the LCD or EVF in the field, but if you check the results afterwards on a good monitor you will find the result might be quite acceptable.

If you find that it is not acceptable, use a non-linear transfer function (usually known as "curves") in your favorite NLE to bring the lowlights back up. For Final Cur Pro, there is a free curves plug-in called Stib's Film Curves which is very nice.

You clearly have a white balance problem in the first image. Make sure you balance to a white surface that is not receiving any blueish light from the sea water. As you can see in the second image, a proper white balance makes 100% white blend better with the rest of the image for a more natural look. If you don't want to fumble around with manual white balance, try leaving the white balance set to one of the camera's presets (daylight) and then do the corrections in post.

Do some experimenting and you will end up with a combination of setting that will get you nearer to what you want.
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Old July 21st, 2004, 03:01 AM   #3
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I did experience something similar a week ago.

I was shooting a sailship over the sea from great distance. There was maybe 5km of water in between and I used the maximum 12x zoom to get it reasonably large.

There was a lot of haze in between and even with a proper UV(0) filter (not a clear protector) the colors were dull. After adjusting the exposure I turned up color in the custom presets and adjusted the white balance shift too (made it warmer). Back home I noticed that I had overcompensated. The white sails had a yellowish cast. Just like the water in the picture.

So maybe it has to do with the custom presets... You should be able to reproduce the yellow on a white paper sheet...

It sure looks like a color problem, not a brightness/contrast issue.

I'm not an expert, but:

Roughly:

Black: (R,G,B)=(0,0,0)
Gray: (R,G,B)=(200,200,200) for example
White: (R,G,B)=(255,255,255)

Yellow: (R,G,B)=(255,255,0) less blue here

So white becoming yellow means that you have too little blue in the image. Try adjusting the "cooler--warmer" preset.

The saturation control would not take the yellow away. It would only make it more grayish (which would be better for water) but it would also desaturate everything else. Not good.

The image with yellow water is properly exposed. The one with white water is overexposed. Overexpose any color and it'll become white: First one RGB value (the largest initially) reaches the maximum value 255. Then the second. Then the third. Finally you get white. In reality it is not white, but the CCD cannot see a difference anymore because of its limited capabilities. A greater color depth (more bits) would probably(?) keep the colour better...

Open a graphics program with a color picker and set (R,G,B)=(255,255,100). Start playing with the luminance setting (increasing it). You can see how the blue value increases and finally reaches 255 -> White. You can do that with ANY color.

Similarly you could pick (255,255,100) and play with the saturation control. You can see how the min and max come closer as saturation decreases, moving the colors closer to a gray (a,a,a).

Various ways of fixing your problem:

A) Make it cooler using the "cooler--warmer" preset

B) If you want to keep the "warm" colors for a certain mood for example, but get rid of the yellow water, then make sure that you overexpose the water enough. The water is very bright and you can overexpose it enough to turn it white while properly exposing the surfer. *Manual exposure or lots of exposure compensation...* Manual exp. would probably be safer (guaranteed overexposure of water at all times). Note that warm colors and BLUE water are mutually exclusive. It's either normal colors and blue water or warm colors and white water.

Increased color saturation makes the problem worse. Decreased saturation makes the yellow grayer but the image becomes dull. Don't use saturation control.

C) Desaturate colors. When there's only shades of gray you will never again have color related problems.

To fix the footage you allready have: Turn the brightness up in the clips where you see yellow. It becomes whiter. I wouldn't desaturate. The yellow would become less noticeable but the sea is so close to gray allready...
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Old July 21st, 2004, 03:07 AM   #4
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Contrast reducing filters do exist (Tiffen Ultra Contrast etc.) and can be bought at bhphotovideo... but I've heard that those filters can be tricky to use. I'll try one next month, though.

A polarizer can be used to remove reflections (brighness) from water. That might help but it could also destroy the mood of the picture. Or then not.
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Old July 21st, 2004, 03:37 AM   #5
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Now when I think about it I believe more and more that you really have a white balancing problem. Not a "cooler--warmer" preference problem.

You probably wouldn't turn the custom presets on and off by accident. Also, the brighter image doesn't look overexposed enough to turn yellow to white. They sea is quite nicely exposed, you see. But, well, I'm not an expert. I'm not sure.

If you manually white balance when it's cloudy or when you are in a shadow or when you shadow the sheet, then the color temperature is higher than in direct sun light. Bluer, that is. When you then manually whitebalance, the shots turn out nice when a cloud drifts in front of the sun. When the sun shines from a clear sky, the colors are too warm.

Also make sure that the paper sheet is NOT OVEREXPOSED when you manually white balance. The sheet is supposed to be neutral gray. A properly exposed (slightly underexposed) sheet would do, but as I have explained the color of the sheet doesn't matter if you overexpose. Even a green sheet would look white when overexposed...
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Old July 21st, 2004, 05:35 AM   #6
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Do you think doing a white balance with a slightly yellow card will work? If I am getting slightly yellow results when using a white card it would make sense to use a yellow card, wouldn't it. The yellow highlights the over exposed parts where white hides it.
You may have solved the problem for me on the white card exposure. I keep it at the same exposure, I'll be sure to lower the exposure when I do a manual white balance next time.
Probably I should just play around with all these various techniques each time I go out to shoot to get the best results for each situation. I might shift WB shift one way to the left cooler next time, I think I may have had it one to the right, this could have also been my problem.
Often after I do a manual white balance I'll have a look at the sand through the camera compared to my eye, it nearly always looks more yellow through the camera. The problem is, I want vivid bright colours (Higher saturation). I normally set colour level 2 to the right and that may cause this. The reason for shifting the custom presets this way is because it always looks better in the lcd, I know I can not trust the lcd outdoors though, most of the time the picture looks alot different once on a televison, no matter how much I try & match them up. Alot of people praise the B&W viewfinder but I miss the colour one on my old cam.
I donno maybe I'm asking too much from a camera of this price.
Any more comments would be cool.
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Old July 21st, 2004, 05:45 AM   #7
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<<<-- Originally posted by Ralf Strandell : I did experience something similar a week ago.

the colors were dull. After adjusting the exposure I turned up color in the custom presets and adjusted the white balance shift too (made it warmer). Back home I noticed that I had overcompensated. The white sails had a yellowish cast. -->>>

This is exactly what I experience, I never seem to learn though because the picture normally looks dull when in the field.
I think no matter how dull it looks, I will leave it from now, if it's too dull I will fix it in post.
What do ya think?
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Old July 21st, 2004, 06:10 AM   #8
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"Do you think doing a white balance with a slightly yellow card will work?"

Better to do it properly with white/grey and leave colored sheets for special effects (and even those are better done in post).

Note that your camcorder sees ultraviolet too. That could affect the white balancing. There are many "white" paper types with varying optical characteristics (due to some chemicals or something). Some are more suitable for white balancing than others, or so have I heard. Still, I'm using ordinary white paper...

You could ask a pro photographer/videographer. They should know.

Adjust the LCD contrast for a more pleasant shooting experience. For very bright conditions you could consider a LCD hood that shadows the LCD...
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