View Full Version : Master Pedestal Setting?
Patrick Roesch August 23rd, 2005, 03:31 PM I'm trying to understand the possible gamma-settings on my XL2.
The effect of "Setup Level", "Knee" (high, medium, low) and "Black" (stretch/normal/press) are obvious to me.
But I have no exact idea what exactly the "Master Pedestal" does...
The Canon Website says: "The Master Pedal controls the starting point of the gamma curve." That can't be true, at least it's ambiguous. Changing the starting point of the gamma curve would be rather like the "black" or "setup level" setting?
Am I missing something?
(looking at the resulting video image, the pedestal setting seems more like a general gamma value)
Jay Gladwell August 24th, 2005, 05:35 AM Take a look at the XL2 Video Tour.
Go to http://www.dvcreators.net/ and click on "Watch the XL2 Feature Tour Video" to see about Master Pedestal.
Jay
Ash Greyson August 24th, 2005, 03:11 PM The master pedestal is used to lighten or darken areas shadowy or dark areas. It is most helpful when you have a stark contrast between your background and foreground...
ash =o)
Patrick Roesch August 27th, 2005, 11:42 AM The master pedestal is used to lighten or darken areas shadowy or dark areas.
...isn't that what the black stretch/press does?
(I assume you know that, of course... but I'm just trying to figure out what exactly the master pedestal and black-stretch functions do. Obviously they both manipulate some part of the low end of the gamma curve, and they do that in a different way...)
Ole Vik January 24th, 2007, 01:22 PM ...isn't that what the black stretch/press does?
(I assume you know that, of course... but I'm just trying to figure out what exactly the master pedestal and black-stretch functions do. Obviously they both manipulate some part of the low end of the gamma curve, and they do that in a different way...)
I'd also like to see more info about the difference between using black stretch/press and the pedestal/setup parameters.
Greg Boston January 24th, 2007, 03:38 PM Master Pedestal is the adjustment of where the curve bends back to the left if viewed on a graph. Black stretch/press determines how fast the curve slopes towards zero after the pedestal starts. Setup is the absolute bottom limit. It's the opposite of white clip, the absolute top limit.
Master Pedestal can be thought of as the opposite of knee point. On some cameras, the knee point can be specified as well as the knee slope.
-gb-
Ash Greyson January 26th, 2007, 08:21 PM Pedestal effect the ENTIRE image, not just the blacks. Though it is not technically correct, I have gotten to where I describe the Setup Level and Master Pedestal as Brightness and Contrast =o)
ash =o)
Greg Boston January 26th, 2007, 10:51 PM Pedestal effect the ENTIRE image, not just the blacks.
With all due respect Ash, Canon and I disagree with you about pedestal. Pedestal gets its name from the more or less flat area that occurs in dark areas before the gamma curve kicks in. IOW, it looks like a pedestal.
From Canon's website regarding the XL2 features...
Master Pedestal (-6 to +6)
The Master Pedal controls the starting point of the gamma curve. This will change the dark areas of the picture.
Are you sure you weren't referring to Master Gamma? That will shift the entire gamma curve up or down but is not adjustable on the XL2.
Jay Lee January 27th, 2007, 03:15 PM My understanding is that the NTSC DV pedestal is 7.5. If the XL2 is set to a Master Pedestal value of 0, is that the same as 7.5 or is it 0? If it is zero, what is the setting to get it to 7.5?
Greg Boston January 27th, 2007, 03:24 PM My understanding is that the NTSC DV pedestal is 7.5. If the XL2 is set to a Master Pedestal value of 0, is that the same as 7.5 or is it 0? If it is zero, what is the setting to get it to 7.5?
You are referring to Setup, and the default value of 0 equates to a setup level of 3.0 IRE according to Canon's website.
Setup is the absolute minimum black level the camera will output. NTSC requires no less than 7.5 IRE because beyond black is where the horizontal and vertical sync pulses occur.
This is all going to go away as we transition away from NTSC analog to ATSC digital.
-gb-
Steve Burke January 28th, 2007, 01:27 AM Gents
Thought I would throw in my experience with these settings.....
BLACKS: Adjusts the 'dynamic range' in the shadows.... does not adjust the lightness or darkness in the range.
[stretch] - emhasises the contrast, and gives you a 'range' of blacks.
[press] - does the opposite, it deepens the darkness and gives you less contrast in the shadows.
EG. Man in black suit next to a black curtain..... [stretch] - separates the man from the curtains. [press] - makes him 'blend' into the curtains, and 'detail' is lost.
MASTER PEDESTAL: Affects contrast AND also adjusts the overall shadow areas.
[-] - Makes dark areas darker AND increases the contrast.
[+] - Makes dark areas lighter AND reduces the contrast.
As you can see there is a subtle difference between these two settings.
Just to complete the picture....
SETUP level is used to adjust the 'black level' of the actual video signal.
[-] - gives you an overall darker picture
[+] - gives you an overall lighter picture and brightens the shadows.
Best thing to do here is to set up the XL2 in a dimly lit room. Connect a monitor to the output ( dont use the viewfinder ) and play with these settings, with the XL2 pointing into a dim corner of the room. Focus on a dark object against a dark background.
Hope this post helps a little with the discussion.
Regards
Steve
Steve Maller January 28th, 2007, 02:27 PM Take a look at the XL2 Video Tour.
Go to http://www.dvcreators.net/ and click on "Watch the XL2 Feature Tour Video" to see about Master Pedestal.
Jay
That video's description of these features is really nice. Thanks for pointing it out.
Mike Palo January 30th, 2007, 09:18 PM Take a look at the XL2 Video Tour.
Go to http://www.dvcreators.net/ and click on "Watch the XL2 Feature Tour Video" to see about Master Pedestal.
Jay
I must be needing glass....cant seem to find the video on this link page?
Steve Burke January 31st, 2007, 06:35 AM I must be needing glass....cant seem to find the video on this link page?
I remember it was on DVcreators some time ago........
Here's an alternative.....
http://syndicate.tentoe.com/canon/DemoMovie/XL2_demo_tour.mov
Hope this helps.
Cheers
Steve
Ash Greyson February 1st, 2007, 12:00 AM With all due respect Ash, Canon and I disagree with you about pedestal. Pedestal gets its name from the more or less flat area that occurs in dark areas before the gamma curve kicks in. IOW, it looks like a pedestal.
I am not talking technical, I am talking practical. I try to explain these things in terms of what makes sense to people. I fully understand the pedestal settings as I am a frequent Vari shooter which has a pedestal for each color. Truth is, with the DV compression and the DV color space, certain terms become murky.
When I say the MP effects the entire image, I mean it effects more than just the BLACK areas. Anything DARK will appear less dark when you turn up the pedestal.
It is all semantics really, the important thing is to understand how these settings PRACTICALLY effect the image and adjust them according to your needs. Out of the box I feel that Canon starts the MP and setup level too high.
ash =o)
Greg Boston February 1st, 2007, 12:36 AM Hey Ash, I guess we could say the terminology is one big 'gray area'. (pun intended)
I was being technical, as you observed. I tend to look at the controls and visualize what part of the response curve is being manipulated by each.
-gb-
Ash Greyson February 1st, 2007, 01:58 AM Well, I nerd out like that too Greg but people really glaze over with too much tech talk. Last time I was on a Vari shoot I was just the tech and by the end of the day the DP was like, "can you just make it look right and not try to explain?"
ash =o)
Jay Lee February 1st, 2007, 11:15 AM Given the explanations so far, what setting do you have plugged into your cameras now for set-up and MP? What setting seem to work best in a variety of shooting situations (inside, outdoors, under lights). I'm really new to the camera, so I'm looking for a solid starting point to max out the performance.
Just as an FYI, my main priority is overall latitude (dynamic range). I will most probably be configuring my cam around one of the cinegamma settings.
Greg Boston February 1st, 2007, 11:48 AM Just as an FYI, my main priority is overall latitude (dynamic range). I will most probably be configuring my cam around one of the cinegamma settings.
If it's latitude you want, I'd suggest you set the Knee to Low, Blacks to Stretch, Setup to 0. Adjust the Master Pedestal to taste. You can do some more tweaking, but that will get you started.
-gb-
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