The downside to what u r doing is is black crush and leads to loss of shadow detail. There a couple of reasons why u r seeing what u r seeing. The gamma in normal mode is funky and does not track well. To start with the gamma is best tracked in cinema mode. Even then it only tracks at 1.9 or so which is bright. I believe true cinema might be slightly better at about 1.9+. Also it is most likely that the u series is coming out of black too fast. There is a setting in the service menu to improve this but shd only be done by someone who knows what they r doing and with a proper meter that can read low light levels. Anyway, I will check on this if I can this weekend. What u hv done is essentially to compromise shadow details for black levels.What u essentially get is compressed dynamic range.

This post has been edited by anfieldude: Dec 31 2010, 09:22 AM

May i ask what do you mean by "coming out of black too fast"?. I break-in my set using the color slides so should have about 200 hrs on the U by now.

And are you suggesting I should set mode to "true cinema" instead?

Thanks.

This post has been edited by Optiplex330: Dec 31 2010, 09:18 AM

That statement is with regards to how the gamma curve is at just above black.
Cinema with warm colour temp or true cinema are more accurate.

I took your advise and tried it out with True Cinema mode. Yes, you are right. The test pattern seems to indicate +2 and actual watching movies seems to indicate 0 (which is better than the previous -2). Still a novice and experimenting. Thanks

I was wondering, if I set Contrast to the maximum, will I be able to have see more details in shadow?

If u set contrast too high, as I explained in the 1st post you will then start crushing whites. U will then start losing details in the bright areas.

hello sifus... wanna ask, I've been struggling to calibrate my hdtv.. i have read this guide and several ones on the net and the picture calibrated in my hdtv is not good enough... since I dun trust my eyes to correctly calibrate I've thinking to buy a colormeter (spyder 2 / spyder 3) and used it with hcfr.. is this an easy task ? have anyone try this?

It is not a simple task.
Get it done the correct way.
Anfieldude did it for me when he came down to KL and it made a BIG difference.

If u want to go DIY, don't get the spyder unless u're using an LCD. I would advise the i2display LT as a minimum. There are better probes than that.

thanks anfieldude & klimal, yeah I'm using LCD and spyder is one of the chepest out there or at least what I have found.

Anyhow just wanted to share a link which I find useful, maybe you guys have known this link

http://www.curtpalme.com/forum/viewtopic.php?t=10457

thinking of trying the guide on think link and see how it goes.

Thats a good site to start. If u hv not bought a spyder I wld advise to get the i2 display as the spyders are inaccurate , sometimes u get lucky sometimes not.

noted..thanks for the advice anfieldude

Hi Anfieldude

Does RGB input into a TV gets gamma corrected as well?? or are all source gamma corrected including 709 spec?

So color space are all gamma corrected?? To what gamma then??

Any reason why we bother to gamma correct the source nowadays when we are going digital?

Thanks!!

This post has been edited by specuvestor: Feb 7 2011, 04:16 PM

spec,

The gamma correction at source (I am using this term as at the studios during mastering/camera) is a little complex. I have been reading and trying to get my head around this using Poynton's material and think I understand it but its a little difficult to put it in words at the moment.

The exact number of gamma correction is up in the air though 2.2 and 2.35 (as final gamma to be viewed from our displays) gets tossed up quite a bit. The problem is the confusion comes as the studios/mastering houses move from reference CRTs to reference LCDs etc.

I think since film stock is what is used for filming final correction is necessary taking into account that it is finally going to viewed by displays that the commoner uses. This is also due to different cameras being used etc. Everything shd be gamma corrected.

I will try to write up something on this soon.

However, in my opinion whenever I calibrate a display I find that somewhere between 2.2 - 2.35 is ok for dimly lit environment (this depends on the viewing environment and the peak white) and for brightly lit areas even as low as 2 is ok.

This post has been edited by anfieldude: Feb 8 2011, 05:50 PM

ya gamma really toughest subject.

What I cannot understand is that it was perfect for CRT and perfect for analog compression

But like you say now using HDTV and all digital. Why still gamma correct at source?? Might as well send an uncorrected image and end user adjust the native picture depending on room lighting

Am wondering if there is any benefit for gamma corrected at source nowadays or it is just a legacy thingy

So all color space are gamma corrected???

I believe its a mix of both. Legacy for sure as overhauling from the cameras to the studios is a painful thing.

Another is I also do not believe that the modern hdtvs are really fully digital (when it comes to light intesity vs voltage) anyway. I have seen some data published by EEtimes that indicates that TFT LCD panels are not totally digital in response and are somewhat similar to the CRTs albeit without a 2.5 function as CRT has.

So I think in order to keep things simple, it would be easier for everyone to agree on a standard gamma correction at source tailored at correcting the natural response of the CRT (so in essence, built in correction at cameras and further correction if necessary at the studios) rather than changing everything to a linear response that is expected (but not practical) by digital hdtvs.

My needs are simple.....I just need Anfieldude to fly to Kuching with his Calman kit.

I thought the gamma correction is standardised at source to be 2.1 (if I remember correctly??) for light emittance nature of CRT?

why is linear response not practical??

solution simple also: just fly him there

This post has been edited by specuvestor: Feb 8 2011, 06:53 PM

Due to the nature of the the need to convert from digital to analogue (ie signal to actual voltage adjustment), there will be losses and natural tendencies of real world stuff to not adhere to a straight line. Of course, this is improving by day, but a lot of the stuff is still analogue.

Gamma correction is normally an inverse of function that a CRT with a fudge factor mostly due to NTSC encoding reasons (so in essence the correction is more like 1/2.2 vs 1/2.5. There is also a linear section near black that needs further correction, so yeah, its a little complicated.

The maths and physics behind video/imaging systems is very intriguing. Spending time understanding the equations is a lot of fun. Literature by Charles Poynton and Bruce Lindbloom are really a must for anyone interested in the science of video/imaging.

ok thanks I only read Poynton... will check out Lindbloom

Lindbloom deals mostly with the mathematical portion.