What's the "secret" of CINE2 ?
 

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%.

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.

Thanks for posting that Steven. Very useful!

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.

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

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/


More on EX1 gamma:
Sony : Shooting Tips for XDCAM EX Concept : United Kingdom

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.