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Sony XDCAM EX Pro Handhelds
Sony PMW-300, PXW-X200, PXW-X180 (back to EX3 & EX1) recording to SxS flash memory.


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Old January 31st, 2008, 02:07 PM   #31
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The best thing to do if you want to know in which extent the GAMMA LEVEL or BLACK LEVEL work, you should simple put a graded chart (from black to white, left to right, linearily) in front of the EX1, and put a good HD-SDI oscilloscope to the hd-sdi output.
Then you will have a representation of the action of the gamma curve.
The Sony F900 have an internal shade you can select (like the SMPTE color bars) so this is more accurate. Maybe that's one thing we could ask for the next firmware upgrade...

In my knowledge, the black gamma setting is working somehow like the "knee" feature. knee is for the top of the curve, as black gamma is for the bottom.
The Gamma LEVEL stretch or collaps the gamma curve on itself.

As said earlier, you will have to work on both settings to achieve the look you want.
Sebastien Thomas is offline   Reply With Quote
Old January 31st, 2008, 02:28 PM   #32
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Sebastian, I did call up the internal color bars which one variant include a black to white strip. Alas the gamma curves don't seem to impact that.

Bill, why not use an 11 step or even a continuous black to white? I'm thinking of doing that myself.

Since I don't have HD-SDI to live scope ability I was thinking of just recording to card and dumping into Final Cut Pro. The internal scopes are at least reasonable.
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Old January 31st, 2008, 03:02 PM   #33
 
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Craig...

Yes, one could certainly do that for themself; and save me the trouble ;o)
The only thing to be aware of is that the absolute white and absolute black points on whatever you generate aren't guaranteed to be 0 IRE or 100 IRE.

When I do it, I use a DSC Labs Camette chart, which guarantees black and white very close to 0 and 100 IRE. Without the calibrated chart, you really don't know what value your pure black and pure white wedges are. I tried what you suggest, and trust me on this, you can't get it right by chance.

The DSC Lab chart I have is a 5 step B&W wedge. The 8 step charts are quite a bit more expensive.
Bill Ravens is offline   Reply With Quote
Old January 31st, 2008, 03:08 PM   #34
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sebastien,
Unless you know something that I'm not aware of its better not to comapre black ganna to a knee setting. Knees are complicated circuits that have point and slop and effect stauration etc.

Better to just think of the 2 gammas as raising or lowering a point in the curve and dragging everything it near it with them. Gamma is somewhere near 50 IRE and Black gamma is probably around 20 IRE but tests could show you exactly where. I haven't tested the camera so I'm just guessing about the IRE numbers, but these are very common circuits in professional cameras.
Leonard Levy is offline   Reply With Quote
Old January 31st, 2008, 07:01 PM   #35
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http://www.bhphotovideo.com/c/produc...cale_Test.html
11 Step for $115


http://www.markertek.com/SearchProdu...rt&pagesize=20
9 step for $39

and the "dangerous" way
http://www.kozco.com/calibrat/gray.html

And yes the expensive variant
http://www.bhphotovideo.com/c/produc..._CamAlign.html
$1900


although I'd really like to see a continuous ramp. As a former video engineer I understand the importance of accurate test charts but in this case it's just to get a general sense of what the PP controls are doing.

Quote:
Originally Posted by Bill Ravens View Post
Craig...

Yes, one could certainly do that for themself; and save me the trouble ;o)
The only thing to be aware of is that the absolute white and absolute black points on whatever you generate aren't guaranteed to be 0 IRE or 100 IRE.

When I do it, I use a DSC Labs Camette chart, which guarantees black and white very close to 0 and 100 IRE. Without the calibrated chart, you really don't know what value your pure black and pure white wedges are. I tried what you suggest, and trust me on this, you can't get it right by chance.

The DSC Lab chart I have is a 5 step B&W wedge. The 8 step charts are quite a bit more expensive.
Craig Seeman is offline   Reply
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