abrupt highlights clipping - Page 21 at DVinfo.net

Go Back   DV Info Net > Sony XAVC / XDCAM / NXCAM / AVCHD / HDV / DV Camera Systems > Sony XDCAM EX Pro Handhelds

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


Reply
 
Thread Tools Search this Thread
Old March 9th, 2008, 12:39 PM   #301
Inner Circle
 
Join Date: Aug 2006
Location: Poland
Posts: 4,086
Quote:
Originally Posted by Michael H. Stevens View Post
Very good point Piort. I knew this and totally forgot the problem of the Zebra #1 95 being 90-100.
Actually, it will appear everywhere between 85 and 105%, Mike.

Quote:
Originally Posted by Michael H. Stevens View Post
Maybe, if you set Zebra #1 to 100, then when zebras FIRST appear you are at 95?????????
It will then appear between 90 and 110%.

None very useful for highlight clipping control. Very good for your main subject (e.g. human skin) controlled exposure.
__________________
Sony PXW-FS7 | DaVinci Resolve Studio; Magix Vegas Pro; i7-5960X CPU; 64 GB RAM; 2x GTX 1080 8GB GPU; Decklink 4K Extreme 12G; 4x 3TB WD Black in RAID 0; 1TB M.2 NVMe cache drive
Piotr Wozniacki is offline   Reply With Quote
Old March 10th, 2008, 05:12 AM   #302
Inner Circle
 
Join Date: Aug 2006
Location: Poland
Posts: 4,086
I think I should add that I find the solution of Zebra1/Zebra2/histogram very useful and properly thought-through by Sony.

- zebra 1 for controlling your main subject exposure (e.g. face skin at around 70%), and only activated when needed (to avoid cluttering of the VF)

- zebra 2 fixed at 100% and always on, to control and prevent clipping when possible

- histogram: this is a bit more complicated, but also works properly. For example, with Cine2 it will never go to the very RH end (zebra 2 is never triggered within the resonable overal exposure of your scene). So, how can one control the highlights exposure? Well, just try this: overexposure by 2-3 stops and - even though the Zebra 2 is still absent - you will notice a vertical bar at the RH end of the displayed histogram range (NOT at 100% - a bit to the left of it). This is because Cine2 will compress highlights enough to never exceed 100% - now turn the exposure down, and you will see this vertical bar going down... Try to make its hight more balanced with the rest of your histogram, and you'll be fine.

With the STD1 being the opposite extreme, the vertical bar can appear at the most RH end of the histogram scale, which of course is confirmed by the Zebra 2: you're clipping at over 100%.
__________________
Sony PXW-FS7 | DaVinci Resolve Studio; Magix Vegas Pro; i7-5960X CPU; 64 GB RAM; 2x GTX 1080 8GB GPU; Decklink 4K Extreme 12G; 4x 3TB WD Black in RAID 0; 1TB M.2 NVMe cache drive

Last edited by Piotr Wozniacki; March 10th, 2008 at 09:02 AM.
Piotr Wozniacki is offline   Reply With Quote
Old March 10th, 2008, 09:57 AM   #303
Major Player
 
Join Date: Sep 2007
Location: Palm Desert, California
Posts: 311
Quote:
Originally Posted by Piotr Wozniacki View Post
- you will notice a vertical bar at the RH end of the displayed histogram range (NOT at 100% - a bit to the left of it). This is because Cine2 will compress highlights enough to never exceed 100% - now turn the exposure down, and you will see this vertical bar going down... Try to make its hight more balanced with the rest of your histogram, and you'll be fine.

.
Thanks Piotr: I have been taking that vertical line right down to zero when using the histogram. I'll try your way.
Michael H. Stevens is offline   Reply With Quote
Old March 10th, 2008, 10:17 AM   #304
Inner Circle
 
Join Date: Aug 2006
Location: Poland
Posts: 4,086
Quote:
Originally Posted by Michael H. Stevens View Post
Thanks Piotr: I have been taking that vertical line right down to zero when using the histogram. I'll try your way.
There's certainly no reason to take it down to zero, Mike - it represents pixels with completely legitimate exposure (brighness) value! Of course, I'm talking now about the cine gammas, which generally prevent from clipping above 100% - compressing everything gracefully much "to the left" of 100% (especially the Cine2 gamma).
__________________
Sony PXW-FS7 | DaVinci Resolve Studio; Magix Vegas Pro; i7-5960X CPU; 64 GB RAM; 2x GTX 1080 8GB GPU; Decklink 4K Extreme 12G; 4x 3TB WD Black in RAID 0; 1TB M.2 NVMe cache drive
Piotr Wozniacki is offline   Reply With Quote
Old March 12th, 2008, 08:42 AM   #305
Inner Circle
 
Join Date: Aug 2006
Location: Poland
Posts: 4,086
Reading about the ongoing problems that so many users have with their camera's vignetting and/or backfocus, I'm thinking the "abrupt highlights clipping" can indeed be treated as a "peculiarity" rather than a flaw...

On the other hand, while the vignetting (or even backfocus, as it seems to depend on the ND filter use) might be difficult to fix (the worst scenario being they're inherent in the design's tight tolerances, and/or ND filter implementation) - the knee/hightlight compression algorithm is a purely software issue, so I'll appreciate input from people like Adam Wilt or Leonard Levy or Tom Roper, who appreciate this problem - it would help greatly in articulating our wishes for some future firmware update in this regard.
__________________
Sony PXW-FS7 | DaVinci Resolve Studio; Magix Vegas Pro; i7-5960X CPU; 64 GB RAM; 2x GTX 1080 8GB GPU; Decklink 4K Extreme 12G; 4x 3TB WD Black in RAID 0; 1TB M.2 NVMe cache drive

Last edited by Piotr Wozniacki; March 12th, 2008 at 09:53 AM.
Piotr Wozniacki is offline   Reply With Quote
Old March 12th, 2008, 10:52 AM   #306
Regular Crew
 
Join Date: Jan 2008
Location: Haiku, HI
Posts: 196
Images: 12
Quote:
Originally Posted by Piotr Wozniacki View Post
There's certainly no reason to take it down to zero, Mike - it represents pixels with completely legitimate exposure (brighness) value! Of course, I'm talking now about the cine gammas, which generally prevent from clipping above 100% - compressing everything gracefully much "to the left" of 100% (especially the Cine2 gamma).
Really only Cine 2 will limit to 100%. On 1, 3 and 4, the curves will deal with the rolling of the whites nicely under 100%, but rescuing whites above 100 can be more work. I think Michael was on the right track. Find Zebra 100, and back off till none. Then use the black level that best pulls the histogram (or waveform) to your floor.

This is what I am considering pushing right "with safety" on this camera.
Randy Strome is offline   Reply With Quote
Old March 12th, 2008, 11:08 AM   #307
Inner Circle
 
Join Date: Aug 2006
Location: Poland
Posts: 4,086
Quote:
Originally Posted by Randy Strome View Post
Find Zebra 100, and back off till none.
Exactly what I've been saying (and doing), Randy.
__________________
Sony PXW-FS7 | DaVinci Resolve Studio; Magix Vegas Pro; i7-5960X CPU; 64 GB RAM; 2x GTX 1080 8GB GPU; Decklink 4K Extreme 12G; 4x 3TB WD Black in RAID 0; 1TB M.2 NVMe cache drive
Piotr Wozniacki is offline   Reply With Quote
Old March 12th, 2008, 11:22 AM   #308
 
Join Date: Nov 2001
Location: santa fe, nm
Posts: 3,264
Images: 10
holy mother of God! I've said that since day 1!
http://www.dvinfo.net/conf/showthrea...=110902&page=9 see post no. 128
Welcome to the club.
Bill Ravens is offline   Reply With Quote
Old March 12th, 2008, 01:34 PM   #309
Inner Circle
 
Join Date: Aug 2006
Location: Poland
Posts: 4,086
But so have I, Bill - like here: http://www.dvinfo.net/conf/showpost....&postcount=174

"- if in manual iris mode, with zebra set to 100%, never allow ANY zebra in the sky (some traces only allowed in pure white areas, like birch barks; the sky - even cloudy - is NEVER pure white so NO zebra there!)"
__________________
Sony PXW-FS7 | DaVinci Resolve Studio; Magix Vegas Pro; i7-5960X CPU; 64 GB RAM; 2x GTX 1080 8GB GPU; Decklink 4K Extreme 12G; 4x 3TB WD Black in RAID 0; 1TB M.2 NVMe cache drive
Piotr Wozniacki is offline   Reply With Quote
Old March 12th, 2008, 02:04 PM   #310
Major Player
 
Join Date: Sep 2007
Location: Palm Desert, California
Posts: 311
Me too....

..................................................
Michael H. Stevens is offline   Reply With Quote
Old March 12th, 2008, 02:09 PM   #311
Major Player
 
Join Date: Sep 2007
Location: Palm Desert, California
Posts: 311
Quote:
Originally Posted by Randy Strome View Post
Really only Cine 2 will limit to 100%. On 1, 3 and 4, the curves will deal with the rolling of the whites nicely under 100%, but rescuing whites above 100 can be more work. I think Michael was on the right track. Find Zebra 100, and back off till none. Then use the black level that best pulls the histogram (or waveform) to your floor.

This is what I am considering pushing right "with safety" on this camera.
JUST SO THERE IS ABSOLUTELY NO CONFUSSION do you mean "black level" and not "black gamma"? If you DO mean "black level" what do you do, if anything, with "black gamma"? Is that just for the internal strech - ie detail vs noise?
Michael H. Stevens is offline   Reply With Quote
Old March 12th, 2008, 02:25 PM   #312
Inner Circle
 
Join Date: Aug 2006
Location: Poland
Posts: 4,086
"Black" shifts the middle (gray) level of the gamma curve, while "Black gamma" is responsible for what on many prosumer cameras is called Black Stretch/Compress.

My experience from the much less light-sensitive (and hence noise-prone) V1 us that if noise is potentially a problem, you'll be better off crushing the blacks to get rid of it (along with details in dark areas, but I personally prefer such picture than a stretched one, with lots of detail and chroma noise).
__________________
Sony PXW-FS7 | DaVinci Resolve Studio; Magix Vegas Pro; i7-5960X CPU; 64 GB RAM; 2x GTX 1080 8GB GPU; Decklink 4K Extreme 12G; 4x 3TB WD Black in RAID 0; 1TB M.2 NVMe cache drive

Last edited by Piotr Wozniacki; March 12th, 2008 at 02:57 PM.
Piotr Wozniacki is offline   Reply With Quote
Old March 12th, 2008, 03:03 PM   #313
Major Player
 
Join Date: Sep 2007
Location: Palm Desert, California
Posts: 311
Quote:
Originally Posted by Piotr Wozniacki View Post
"Black" shifts the middle (gray) level of the gamma curve, while "Black gamma" is responsible for what on many prosumer cameras is called Black Stretch/Compress.

My experience from the much less light-sensitive (and hence noise-prone) V1 us that if noise is potentially a problem, you'll be better off crushing the blacks to get rid of it (along with details in dark areas, but I personally prefer such picture than a stretched one, with lots of detail and chroma noise).
Piotr: I know quite well what Black Level and Black Gamma are I was asking Randy wht settings he used.
Michael H. Stevens is offline   Reply With Quote
Old March 12th, 2008, 03:12 PM   #314
Inner Circle
 
Join Date: Aug 2006
Location: Poland
Posts: 4,086
Oh, sorry - was reading too fast :)
__________________
Sony PXW-FS7 | DaVinci Resolve Studio; Magix Vegas Pro; i7-5960X CPU; 64 GB RAM; 2x GTX 1080 8GB GPU; Decklink 4K Extreme 12G; 4x 3TB WD Black in RAID 0; 1TB M.2 NVMe cache drive
Piotr Wozniacki is offline   Reply With Quote
Old March 12th, 2008, 06:25 PM   #315
Regular Crew
 
Join Date: Jan 2008
Location: Haiku, HI
Posts: 196
Images: 12
Quote:
Originally Posted by Piotr Wozniacki View Post
"Black" shifts the middle (gray) level of the gamma curve, while "Black gamma" is responsible for what on many prosumer cameras is called Black Stretch/Compress.
There are a lot of settings, and as always I claim no expertise. That said, my understanding is different than Piotr's.

I think visually, so in terms of curves:

Black level, (called just "Black" in PP) is your master black and sets only the black point. Middle Gray is shifted by "Gamma". "Black Gamma" Would be like setting a point on the lower region of the curve and adjusting from there.

I have been leaving the Gamma and Black Gamma settings alone, but I am sure I will start to meddle with those too.
Randy Strome is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > Sony XAVC / XDCAM / NXCAM / AVCHD / HDV / DV Camera Systems > Sony XDCAM EX Pro Handhelds

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 05:02 PM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network