abrupt highlights clipping

[Piotr Wozniacki]

Originally Posted by Randy Strome

The "flat spot" is present in all PP's and is very relevant to me, because it explains a lot about how whites are being handled.

Guys, referring to the last development in that other thread - how do you interpret the "abrupt clipping" phenomenon, in the light of SAW results?

[Randy Strome]

Hi Piotr,

No idea what is happening with individual color handling up there. All I can tell you, is that the luminance curve flattens at it's highest value on each PP.

When looking at the curves in the brochure, I had been confused as to why the curves all ended at a different point on the horizontal axis, but now it makes sense. In actuality, the top value simply flat-lines to the right after the final depicted point. I think that is valuable to know.

[Piotr Wozniacki]

What I'm wondering is this: with STD curves, when you change the knee point and particularly the SLOPE value - what does the flat fragment look like?

[Randy Strome]

Originally Posted by Piotr Wozniacki

What I'm wondering is this: with STD curves, when you change the knee point and particularly the SLOPE value - what does the flat fragment look like?

Hi Piotr,

Probably easier for me to snap some shots and show you. Are you interested in a particular Gamma, say STD 3?

[Piotr Wozniacki]

Originally Posted by Randy Strome

Hi Piotr,

Probably easier for me to snap some shots and show you. Are you interested in a particular Gamma, say STD 3?

Randy - all, if possible, please! But of course I appreciate your time and effort :)

The thing is that while the CINE curves are depicted in the brochure, the STD ones cannot be found anywhere...

[Michael H. Stevens]

Originally Posted by Randy Strome

Hi Piotr,

Probably easier for me to snap some shots and show you. Are you interested in a particular Gamma, say STD 3?

Randy: I would like to see screen snapshot of Cine 1 and 4. But please tell me what is "SAW"?

[Raimis Sausainis]

Dzen dobri Piotr:)
Maybe you filmed candle's flame? If no...maybe you can try this test? Would be very interesting,thanks:)

[Piotr Wozniacki]

Dzien dobry, Raimis :)

Filming candle flames is something that naturally requires a lot of attention to properly exposing, thus is less prone to exhibit the "abrupt clipping" effect than those seemingly easy shots outside, with plenty of light...

Or do you mean some other peculiarity that might be revealed?

[Raimis Sausainis]

For me interesting how will does EX1 this test with candle,for example HDV sony compression has artefacts around flame:(

[Piotr Wozniacki]

Compression is one thing (and of course the 35Mbps VBR of the XDCAM EX HQ codec is far superior to HDV), but how this area is rendered depends mainly on the imagers (CMOS will give you the halo, while CCD - the ugly, vertical smear).

This thread, however, has dealt with something quite different; I'm sure you're aware of that :)

[Raimis Sausainis]

Dzenkuja barzo for your answer Piotr!:)
But if you'll have free time,would be interesting how XDCAM EX HQ codec will pass this test with candle:)

[Piotr Wozniacki]

I will, Raimis. But considering it's also CMOS, expect the halo to be there, as well. Certainly close to none compression artefacts, though...

[Raimis Sausainis]

I saw these artefacts with consumer camcorders HDR-HC1,HC3,HC5,HC7 and new HC9E(AVCHD camcorders have not this problem) and i tested with candle semi pro camcorders HVR-A1,V1,FX1,FX7...everywhere is same problem:) I'll hope everything is fine with amazing EX1/3 camcorders:)

[Piotr Wozniacki]

Guys,

To sum this thread up somehow (being one of the longest in this forum, it kinda deserves it :), I must say that after mastering my EX1 I don't find the "abrupt clipping" phenomenon as disturbing as I initially thought. I must agree with Adam Wilt that the problem is practically absent with CINE gammas (though it can show its ugly head from time to time, as well).

As to the STD curves, I find it appear most often when using STD3 (which is strange, as this is the default gamma, in force when you don't use any PP). STD1 and STD4 I'm using almost exclusively with my PP's for indoor, lowlight shooting (when I need to either get a punchy look, or stretch blacks - respectively); in this sort of lighting the abrupt clipping is practically non-issue at all.

Nevertheless, for purely academic reasons, I'd like to see some well-grounded recipe for knee adjustments that would control the phenomenon even with STD curves outdoors. Also, I wonder is Sony's going to address it in future firnware releases (or rectify it in the EX3, for that matter)...

[Piotr Wozniacki]

Further on the above, I'd like to encourage everyone to try and experiment with the KNEE APERTURE settings (this is a function to tune edge enhancement solely in areas, affected by the highlights compression, i.e. to the right of the KNEE point):

http://pro.sony.com/bbsccms/assets/f...ture_Edges.pdf

My experiments (though yet inconclusive) tend to show that the default setting of KNEE APERTURE is not the best one, and may add to this "abrupt clipping" phenomenon. Along with the KNEE Saturation and SLOPE, it can be set to get rid of this ugly effect altogether; pity though that the default settings (especially with the STD3 gamma) are such that with run&gun shooting style, it's not always possible...

I'm very curious of your own observations.