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Sony XDCAM EX Pro Handhelds
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Old January 31st, 2008, 08:01 AM   #16
 
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Piotr...

I'm getting confused. I refer strictly to the Profile menu settings for the EX1. BLACK effects only the master black level.

On page 75 of the US Owner's manual....very top of the page are the Gamma settings: LEVEL(-99>0>+99) and SELECT(STD1,2,3,4,CINE1,2,3,4). I refer to the LEVEL setting...negative values compress blacks, positive values stretch black. Note that the reference level at zero, changes according to which Gamma SELECT value you pick.
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Old January 31st, 2008, 08:12 AM   #17
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Piotr...

I'm getting confused. I refer strictly to the Profile menu settings for the EX1. BLACK effects only the master black level.

On page 75 of the US Owner's manual....very top of the page are the Gamma settings: LEVEL(-99>0>+99) and SELECT(STD1,2,3,4,CINE1,2,3,4). I refer to the LEVEL setting...negative values compress blacks, positive values stretch black. Note that the reference level at zero, changes according to which Gamma SELECT value you pick.
All this is fine Bill (my EU manual says the same ;)). BUT, there is a separate BLACK GAMMA setting (regardless of which gamma curve you select), and I thought THIS is responsible for the black compensation. Hence the confusion...
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Old January 31st, 2008, 08:46 AM   #18
 
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The BLACK GAMMA setting is an unknown. The manual says it affects the noise level in the black areas. It did not seem to greatly affect the black level or knee position when I adjusted it while connected to a WFM.
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Old January 31st, 2008, 08:54 AM   #19
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Originally Posted by Piotr Wozniacki View Post
All this is fine Bill (my EU manual says the same ;)). BUT, there is a separate BLACK GAMMA setting (regardless of which gamma curve you select), and I thought THIS is responsible for the black compensation. Hence the confusion...
That is correct. I believe what Bill is looking at on the gamma curves page may be an adjustment on the bigger cameras called master gamma. This will shift the entire gamma curve up or down without changing the shape of the response (like a positive or negative bias).

Black Gamma compresses/stretches the blacks.

Then there will be settings for black as Bill indicated that set up the start of the lower knee known as pedestal. Then there will be one that sets the minimum black level known as set-up. It's just that Sony has their own terms for these settings.

-gb-
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Old January 31st, 2008, 08:57 AM   #20
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The BLACK GAMMA setting is an unknown. The manual says it affects the noise level in the black areas.
What the manual means by that is you'll get less noise if you dial it down to crush the blacks.

Black Gamma is not unknown, it is Sony's stretch/compress adjustment.

regards,

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Old January 31st, 2008, 09:05 AM   #21
 
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Greg...

Thanx for weighing in. Sony sure does confuse things with their esoteric nomenclature. You're right about BLACK GAMMA. Still, when adjusting GAMMA LEVEL, the entire gamma curve is shifted, in a much more dramatic way than with the BLACK GAMMA. GAMMA LEVEL does more than shift the entire gamma curve up and down. The endpoints, both high and low, remain unchanged while the midpoint moves up and down. To me, that looks more like a compress/stretch. For example, in the True Color calibrations I performed, I found a STD3 with a gamma level of 0 is equivalent to CINE1 with a gamma level of -40. There may be more going on with the shape of the curve, but this is true for the midpoints.
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Old January 31st, 2008, 09:11 AM   #22
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Greg...

Thanx for weighing in. Sony sure does confuse things with their esoteric nomenclature. You're right about BLACK GAMMA. Still, when adjusting GAMMA LEVEL, the entire gamma curve is shifted, in a much more dramatic way than with the BLACK GAMMA. GAMMA LEVEL does more than shift the entire gamma curve up and down. The endpoints, both high and low, remain unchanged while the midpoint moves up and down. To me, that looks more like a compress/stretch.
So - if I got your right, Bill - setting the GAMMA LEVEL (with any gamma curve selected) UP will make it more S-shaped, thus stretching blacks and compressing highs? And consequently, lowering the GAMMA LEVEL will compress blacks and stretch highs?

Well, this is how I understand your statement about the endpoints remaining unchanged, while the entire curve gets shifted up or down...

Anyway, your PP2 preset has both the GAMMA LEVEL (entire curve shift, CINE1 in this particular case), and BLACK (master pedestal) cranked down, which is what I'm after for low contrast / dull scenery...
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Old January 31st, 2008, 09:30 AM   #23
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I had a conversation much like this thread with Juan Martinez of Sony. He said he would try to get more info up on their website.

Sony PLEASE DO ASAP!

What we really need to see (IMHO) is a proper test chart and scope output showing EXACTLY how all these settings affect things.
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Old January 31st, 2008, 09:39 AM   #24
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I had a conversation much like this thread with Juan Martinez of Sony. He said he would try to get more info up on their website.

Sony PLEASE DO ASAP!

What we really need to see (IMHO) is a proper test chart and scope output showing EXACTLY how all these settings affect things.
Ditto; Amen.
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Old January 31st, 2008, 09:40 AM   #25
 
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Piotr..

yes, now you understand what I do.
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Old January 31st, 2008, 09:47 AM   #26
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Piotr..

yes, now you understand what I do.
Uff.. This is a happy end, as all the three of us (Bill, Greg and myself) were meaning basically the same.

Which doesn't invalidate Craig's call for Sony to come and clarify all down to the tiniest detail...
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Old January 31st, 2008, 11:03 AM   #27
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Greg...

Thanx for weighing in. Sony sure does confuse things with their esoteric nomenclature. You're right about BLACK GAMMA. Still, when adjusting GAMMA LEVEL, the entire gamma curve is shifted, in a much more dramatic way than with the BLACK GAMMA. GAMMA LEVEL does more than shift the entire gamma curve up and down. The endpoints, both high and low, remain unchanged while the midpoint moves up and down. To me, that looks more like a compress/stretch. For example, in the True Color calibrations I performed, I found a STD3 with a gamma level of 0 is equivalent to CINE1 with a gamma level of -40. There may be more going on with the shape of the curve, but this is true for the midpoints.
Ok, that's probably a better choice of words than I used. Gamma Level (called Master Gamma) is shifting the middle of the curve but what I meant to emphasize is that the 'shape' of that curve remains unchanged. I didn't mean everything from top to bottom as gamma is really defined as the alteration of mid tone response anyway.

Quote:
In photography, gamma refers to the slope of the straight-line region of the sensitometry curve (Hurter–Driffield curve), which is a plot of density (or the logarithm of opacity) of the film image versus the logarithm of the film's exposure to light.
The 'straight line region' more or less means excluding the knee and highlights as well as pedestal and blacks.

If you view the gamma correction as that 'bulge' in the middle which would be a straight line uncorrected, then gamma level simply makes that bulge move up or down, but doesn't alter the curve of the bulge.

Sorry for the vague wording.

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Old January 31st, 2008, 11:46 AM   #28
 
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If it would be of benefit, I can take some screen grabs of the WFM, while looking at a 5 step black wedge under different gamma presets; and, post them here. Before I do it, tho', I want to know if it would be useful to anyone.
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Old January 31st, 2008, 11:49 AM   #29
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If it would be of benefit, I can take some screen grabs of the WFM, while looking at a 5 step black wedge under different gamma presets; and, post them here. Before I do it, tho', I want to know if it would be useful to anyone.

Absolutely Bill - it'll be a great reference!
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Old January 31st, 2008, 01:39 PM   #30
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Gamma on all video cameras refers to a control that moves the aproximate midpoint of the curve up or down. This will affect the shape of the curve - it has to.
The effect of high gamma is to make flesh tones lighter and bring up the low to middle end which gives a less saturated less moody picture.
It will compress the higher end but won't affect the areas near the top, so the main affect is to bring up mids and shadow areas. But it doesn't give your picture alot of character so people generally like to drop the gammas a bit.
Dropping Gamma tends to produce a more "filmlike image" saturated darker image even though that word probably has no technical meaning in this context. By the way on many professional characters lowering the gamma is done by raising the number on the menus. Usually runs between say 35 and 55 with 40 or so being average and 55 being lower.

However when you lower Gamma you might tend to crush the shadow area , so cameras started coming ourt with a Black Strech or Black Gamma to give you a control somewhere in the 20 IRE area ( that's just a guess on the IRE). So you can open up or crush your shadow area without affecting your actual bottom black level. Raising black gamma can increase noise and crushing it can lower noise, but you are also affecting your picture not just the noise. Ex doesn't have bad noise to me so I would just go by what l wanted to see.

The Black Level or Pedestel is simply the bottom of the picture - Capped black level. When you raise or lower either gamma this stays the same and everything else stretches or condenses against it. They settings will all affect each other though. When you say raise the mid Gamma it will pull the shadows up all the way from the Black level, but you could pull them down again with Balck Gamma and maybe affect the mid gamma or stuff right beneath it a touch.

( Are there 2 black level controls on the EX-1 like someone here said? - I didn't see that and would noit be familiar with that so maybe that's yet another wrinkle)

The Cine gammas add another wrinkle that is a bit of voodoo that some serious engineers don't like because the manufacturers don't like to post what they do.

I've been told that cine gammas use a modified knee function that is set to come in way earlier than the knee usually does. A tech I know said that some Panasonic cine gammas started working at 30IRE! This is just hearsay to me as I haven't tried to analyse them. However that's supposedly why you usually don't have knee settings on cine gammas.
(I'm open to hearing other interpretations and it would be nice if a Sony rep chimed in.)

I don't know the difference between the EX's cine gammas. maybe they all have the same basic cine gamma setting (the voodoo) with different mid and black gammas, or maybe they each have a different "voodoo setting"
Whatever it is, the cine gamma would of course change your curve shapes and modifying the cine gammas by altering the other gammas could start to make them similar.

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