Hi :)

I always thought that the different preset Gammas (STD 1 to 4 and CINE 1 to 4) are nothing more that different S-Shapes of gradation curves. And steping though them it semms exactly like that.

But ... wait ... there is CINE2 which completele eliminates zebras on highlights.

What is that difference ? Does it a somehow "magic" roll off, that doesn't clip the highlights? Surely not, but why are there no more zebras at all ?

And BTW I have Zebra at 107.

In general I am reconsidering my opinions a little.
As mentioned, I alway thought it's good to shoot as shallow as possible (with things like black stretch) and then do the S-curve in post. To have enough access to darker parts if needed.

But that never saves one from clipping. So I am wondering now, if it's maybe a good idea to use those cine Gammas. Especially number 2.

Who knows more about that or can give me some recommendations ?

Thanks!

Peter

Peter, I can't answer your question.

However, I'm curious as to why you have your zebra set at 107.

Cine2 is a "special" gamma curve designed to prevent illegal superwhites and superblacks. The knee in the built in gamma rolls off illegal values and remaps them to broadcast legal. It does not clip these values.

Jay:
To get the most in dynamic range I try do avoid cliping. 107 shows me when it's absolutely end of range. Lower zebra values warn you in advance, although it's not really clipped.

Bill:
I was suspecting something like that, but somehow hoped, that maybe the sensor could take much more than the resulting 8-Bit and that CINE2 would compress it in.

Thanks!

Peter

Cine1 is better at doing that, I think.

Adam Wilt (well respected in my book!) has a decent summary on the EX1 gamma curve selections:

• STD1 – “bright and contrasty”. Blacks slightly crushed, whites slightly crushed, increased contrast, midgray at 55%.
• STD2 – “deep blacks”. Blacks slightly crushed, rest of tonal scale stretched downward; midgray at 48%.
• STD3 – “standard video”. Normal, midgray at 50%.
• STD4 – “black stretch”. Blacks slightly stretched, increased shadow detail, midgray at 55%.
• CINE1 – “deep cine”. Compression starts around 80%; midgray at 37%.
• CINE2 – “broadcast safe cine”. CINE1 rescaled with whites limited to 100%.
• CINE3 – “brighter cine”. Compression starts around 65%; midgray at 45%.
• CINE4 – “video-bright cine”. Compression starts around 65%; midgray at 50%.

Jay:
To get the most in dynamic range I try do avoid cliping. 107 shows me when it's absolutely end of range. Lower zebra values warn you in advance, although it's not really clipped.

Hmmm... Never heard that one before.

Jay...

I agree. If you want the most dynamic range, use 107% zebra as an absolute upper limit. Beware, however, that if you see zebra, clipping is occuring and you're losing data, as there's no headroom left. Also, using superwhite during rcording presupposes that your NLE will deal with the superwhites to bring them into legal limits for the final product. Setting and exposing for zebra of 100% is throwing away a few useful bits of data...like 14% of the camera's capability.

Note that Zebra 1 is + and - 10%.
Zebra 2 (hard wired to 100%) shows what is over 100%
See page 41 of the manual.

Adam Wilt ...has a decent summary on the EX gamma curve selections:

• STD1 – “bright and contrasty”....
• CINE4 – “video-bright cine”. Compression starts...

Thanks for posting that Steven. Very useful!

Jay...

Setting and exposing for zebra of 100% is throwing away a few useful bits of data...like 14% of the camera's capability.

How is that extra "7" of 107 amounting to 14% of the camera's capability?

I'll have to do some tests and see how they turn out.

Adam Wilt (well respected in my book!) has a decent summary on the EX1 gamma curve selections:

• STD1 – “bright and contrasty”. Blacks slightly crushed, whites slightly crushed, increased contrast, midgray at 55%.
• STD2 – “deep blacks”. Blacks slightly crushed, rest of tonal scale stretched downward; midgray at 48%.
• STD3 – “standard video”. Normal, midgray at 50%.
• STD4 – “black stretch”. Blacks slightly stretched, increased shadow detail, midgray at 55%.
• CINE1 – “deep cine”. Compression starts around 80%; midgray at 37%.
• CINE2 – “broadcast safe cine”. CINE1 rescaled with whites limited to 100%.
• CINE3 – “brighter cine”. Compression starts around 65%; midgray at 45%.
• CINE4 – “video-bright cine”. Compression starts around 65%; midgray at 50%.

please forgive me, but what does it mean when the "compression starts at _% and midgray at _%"?

thanks.

Jay...

The 14% includes superwhite, as well as superblack.
[255-(235-16)]/255

please forgive me, but what does it mean when the "compression starts at _% and midgray at _%"?

thanks.

Mike, in Adam's test, he listed the brightness for middle gray on a chip chart in each gamma for the same exposure setting, with 50% being the default. He used STD3 (linear gamma) – “standard video”. Normal, midgray at 50 to use as the basis for setting up this exposure as the main baseline reference for all other gammas. The "compression starts" is the first point on the line where the exposure starts to compress and turn non-linear.

You can read Adam's detail here:
awilt/story/review_sony_pmw_ex1_1_2_3_cmos_hd_camcorder/P3/ (http://provideocoalition.com/index.php/awilt/story/review_sony_pmw_ex1_1_2_3_cmos_hd_camcorder/P3/)


More on EX1 gamma:
Sony : Shooting Tips for XDCAM EX Concept : United Kingdom (http://www.sony.co.uk/biz/view/ShowContent.action?product=PDW-700&site=biz_en_GB&category=XDCAMCamcorders&contentId=1193315622112&sectiontype=Product&preserveContext=true)

Note that Zebra 1 is + and - 10%.
Zebra 2 (hard wired to 100%) shows what is over 100%
See page 41 of the manual.

Indeed it is right in the manual as so but on page 56 of the paper manual & page 55 of the electronic version.

I didn't catch the plus or minus 10% when I read it the first time.

I should say I'm looking at EX1 Paper Manual. Is that the EX3 Manual you're referring? I just want to make sure we don't drive people crazy looking in the wrong manual. I suspect much of the basic information is similar but obviously in different places in each.

Indeed it is right in the manual as so but on page 56 of the paper manual & page 55 of the electronic version.

I didn't catch the plus or minus 10% when I read it the first time.

I could be wrong, but....

The manual says a 10% range on Zebra 1. That's plus or minus 5% from whatever you have set.. At least in my camera, if I set Zebra 1 at 95% I get zebras in the range from 90% to 100% (as measured by the brightness display).

I don't often have people as the main subjects, so I'm more concerned about blowing out highlight detail. That's why I have Zebra 1 set at 95%.

Pete

Mike, in Adam's test, he listed the brightness for middle gray on a chip chart in each gamma for the same exposure setting, with 50% being the default. He used STD3 (linear gamma) – “standard video”. Normal, midgray at 50 to use as the basis for setting up this exposure as the main baseline reference for all other gammas. The "compression starts" is the first point on the line where the exposure starts to compress and turn non-linear.

You can read Adam's detail here:
ProVideo Coalition.com: Camera Log by Adam Wilt | Founder | Pro Cameras, HDV Camera, HD Camera, Sony, Panasonic, JVC, RED, Video Camera Reviews (http://provideocoalition.com/index.php/awilt/story/review_sony_pmw_ex1_1_2_3_cmos_hd_camcorder/P3/)


More on EX1 gamma:
Sony : Shooting Tips for XDCAM EX Concept : United Kingdom (http://www.sony.co.uk/biz/view/ShowContent.action?product=PDW-700&site=biz_en_GB&category=XDCAMCamcorders&contentId=1193315622112&sectiontype=Product&preserveContext=true)

thanks steven.
i'm still not 100% what exposure "compression" is. could someone elaborate?
thanks. Happy New Year!

My manual says ±10% not 10% range. Setting Zebra 1 to 107 can trigger at 97. Setting Zebra 1 to 95 can trigger at 85.

The exact wording in my EX1 Manual page 41:

To display a zebra pattern in the area of ±10% centering the video level set with "Zebra Level."

My translation: The number you set Zebra 1 to is the middle of the range. That range starts -10% and ends +10%

Setting zebra to 95 would be 85-105 range.

This is different than Zebra 2 which is locked to 100% and only displays over that number.

from the manual on Zebra 2:

To display a zebra pattern for the video level over 100%.

So, if you want zebra 1 to start displaying at 95% set zebra 1 to 105%. Zebra 1 is the CENTER of it's ±10% range.

Zebra 2 wont display until it hits 100% (there's no under to the range).

It would nice to have a zebra trigger point at 107% since anything below that still has data that can be used/rescued/not clipped.

I could be wrong, but....

The manual says a 10% range on Zebra 1. That's plus or minus 5% from whatever you have set.. At least in my camera, if I set Zebra 1 at 95% I get zebras in the range from 90% to 100% (as measured by the brightness display).

I don't often have people as the main subjects, so I'm more concerned about blowing out highlight detail. That's why I have Zebra 1 set at 95%.

Pete

Craig, I know what the manual says. I'm pointing out that MY camera doesn't work that way. Set at 95% I get zebras in areas that range from 90% to 100%, as measured by the Brightness Level Indication in the viewfinder.

Please try yours and let me know how yours works.

Whether my camera is unique (doubtful) or the manual's writers were less than clear (more likely) is not a problem for me. I like the smaller range. Zebra's covering 20% of the exposure range would not be much use to me. Set at 95%. I can tell what parts of the image will be very light gray to white without blowing.

Pete

I should say I'm looking at EX1 Paper Manual. Is that the EX3 Manual you're referring? I just want to make sure we don't drive people crazy looking in the wrong manual. I suspect much of the basic information is similar but obviously in different places in each.

Hi Craig, yes it's the EX3 manual (laughing). It occurred to me after I was away from my computer today that you were talking about the EX1 manual. I apologize if I caused any confusion.