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-   -   Cine gamma settings in the EX1 (https://www.dvinfo.net/forum/sony-xdcam-ex-pro-handhelds/237806-cine-gamma-settings-ex1.html)

Simon Denny June 22nd, 2009 08:43 PM

Cine gamma settings in the EX1
 
I’m trying to find some info on the Cine gamma settings in the EX1 and how or what each setting is doing.
I currently use Cine 4 for all types of shooting indoor and outdoor but often find that the top end whites seem to be a bit milky or washed at times with Cine 4.
I’m experimenting now with Cine 1 but would like a bit more knowledge if the top end whites are being compressed or a Knee is applied.
Cine 1 seems good for outdoor shooting in bright natural light but is a bit dark for indoor shooting under lights I find.
I’m thinking of Cine 4 for indoor and Cine 1 for outdoor.
Can anyone shed their experience using different Cine’s for indoor or outdoor shooting.

Thanks

Robert Young June 22nd, 2009 11:48 PM

The entire picture profile topic- including the Cine Gammas- is rather complicated. You should definitely browse thru the Picture Profile Settings thread at the top of the forum, in the "Sticky" section.
However, as a basic concept, I think of Cine 1 as having more dynamic range. It is good for bright, colorful, high contrast outdoor shots. If you use auto iris, the footage will tend to be underexposed. I shoot manual iris and push the histogram towards the right, often allowing a little 100% zebra on the hot spots for Cine 1.
Cine 4 is good for lower light, lower contrast scenes and auto iris is usually pretty close to right on. Actually, Cine 4 is a good, reliable, all around gamma setting, particularly for run n' gun shots.
There is a huge amount of info & opinions on this stuff- probably more than you want to know, but in Adam Wilt's original review of the EX1:
ProVideo Coalition.com: Camera Log by Adam Wilt | Founder | Pro Cameras, HDV Camera, HD Camera, Sony, Panasonic, JVC, RED, Video Camera Reviews
he provides very good summary information regarding most of these settings. When I read carefully & gave it some thought, I was able to come away with some very useful concepts, a sort of basic framework for understanding what its all about.

Simon Denny June 22nd, 2009 11:58 PM

Thanks Robert,
I shoot manual everything and have, are re-reading all the posts I can find.
Thanks for the link I forgot that one.

Cheers
Edit: I just found on the Sony brochure the cuve diagram which shows the Cine curve for each cine.
Also on the Sony UK site. XDCAM EX Shooting Tips: Issue 7 shows some diagrams

Alister Chapman June 23rd, 2009 12:46 AM

I have been doing a lot of research into the best gammas to use on the EX's for different lighting situations. The cinegammas are designed for shooting footage that will be graded, the images they produce are not entirely natural looking, however they do maximise dynamic range by compressing highlights and at the same time allocating a large part of the recorded signal range to mid tones and shadow detail. This is why shadows can look washed out or milky. However this also gives you more to play with in the grade.

Cinegamma 1 is tailored for shooting bright scenes or scenes where there will be large areas of highlights. CG1 is tailored for maximum highlight handling with lower shadow dynamic range compared to CG3 and CG4.
Cinegamma 2 is essentially the same as CG1, except the overall level is reduced making it broadcast safe at 0db. Cinegammas 1,3 and 4 all record up to 109% at 0db and 104% at -3db.
Cinegamma 3 has strong highlight compression but the compression starts later than CG1 so it's not as compressed as CG1. Midtones and shadows are stretched more than CG1. This gives more dynamic range to mid tones and shadows compared to CG1 at the expense of some highlight handling.
Cinegamma 4 is similar to CG3 but with the mid tones lifted still further so that it gives a brighter looking picture overall.

My preference is to use CG1 for outdoor, brightly lit scenes or scenes where highlight handling is critical. Then I use CG3 for indoor and scenes on dull days where extreme highlight handling is less critical, but shadow detail becomes more important. What I have also found is that when shooting interviews the cinegammas work best when they are slightly under exposed compared to standard gammas and then graded in post. If using cinegammas I tend to expose skin tones at around 60%.

Cinegamma 1 on the EX is the same as Hypergamma HG4 on the PDW-700, F900R etc and cineegamma 2 is the same as Hypergamma HG2. With CG1/HG4 : 460% D-range is compressed to 109%.

Serena Steuart June 23rd, 2009 12:50 AM

1 Attachment(s)
Cine4 provides the greatest dynamic range but that doesn't make it best for all situations. It rolls over highlights more than the other gammas (see attached) so if you want contrast in those regions (e.g. sunsets) you're better off with cine1. Cine4 gives you a lot of latitude for good middle exposure without clipping highlights, but you need your important areas of the image in the more linear portion of the gamma curve. Exposing to put the histogram to the far right (as the guiding principle) is likely to over expose important parts of the subject, rendering skin (for example) in unfortunately orange tones. Having said that, Cine4 is my default setting.

EDIT: that was written before seeing Alister's note. Good point about grading in post --- I tend to assume that and forget to mention it.

Simon Denny June 23rd, 2009 01:43 AM

Alister,
I watched your presentation on the Sony site with footage taken from the EX1 and this got me thinking that Cine 4 was blowing the highlights out on certain situations.
Cine 4 seems to have the best overall brightness for a particular indoor setup but I guess as will most things it’s one’s own personal taste.
I have copied this fron the Sony site so I hope this is within the rules?
• CINE1 preset smoothes the contrast in darker areas and accentuates gradation changes in brighter areas.
• The CINE2 preset gives almost the same results as CINE1, and limits video signals under 100% video level.
• Select CINE2 when you wish to limit video signals under 100% video level in case you have constraint in white level head room at 100% in post production environment.
• The CINE3 preset emphasizes the contrasts in bright and dark areas more than CINE1 and CINE2, and accentuates gradation changes on the black side.
• The CINE4 preset emphasizes the contrast in dark areas more than CINE3. (Contrast in dark areas is weaker than STD3, and contrast in brighter areas is stronger.)

Edit:
Serena,
Not sure I understand that graph with Cine 2 and 3. Are they being clipped at 65 and 80.

Serena Steuart June 23rd, 2009 02:06 AM

Simon, not being clipped. I was only interested in comparing 1 and 4 to STD 1, so didn't do the extra work. The curves go to 109, but I stopped at 100.

Those Sony descriptions of the gammas I always found rather uninformative (other than cine2), even after I quantified the actual curves.

Simon Denny June 23rd, 2009 02:24 AM

Yeah Cine 2 is clipped or rolled off to be legal it looks like.
I'm with you on Sony's gamma descriptions.

Alister Chapman June 23rd, 2009 01:08 PM

Serena, I think leaving out the top 10% of the curves is a mistake as much of the important highlight compression takes place in the top end of the curves. The top 15% of the cinegammas can contain as much as 40% of the input signal and this has a great bearing on how bright scenes will look.

Bill Ravens June 23rd, 2009 01:59 PM

Quote:

Originally Posted by Alister Chapman (Post 1162433)
Serena, I think leaving out the top 10% of the curves is a mistake as much of the important highlight compression takes place in the top end of the curves. The top 15% of the cinegammas can contain as much as 40% of the input signal and this has a great bearing on how bright scenes will look.

I would agree. It seems from Serena's curve extrapolations, that Cine3 might actually yield higher latitude than C4 or even C1, depending on where things get clipped at 109%. The problem with extrapolations are that they are based on some mathematical model/curve fit routine. It is extremely difficult to decide what algorithm gives the best fit, so everything is a rather of a guess.

Serena Steuart June 23rd, 2009 09:05 PM

Quote:

Originally Posted by Alister Chapman (Post 1162433)
Serena, I think leaving out the top 10% of the curves is a mistake as much of the important highlight compression takes place in the top end of the curves. The top 15% of the cinegammas can contain as much as 40% of the input signal and this has a great bearing on how bright scenes will look.

I agree with the comments. The trend indicates how each curve will treat highlights, confirmed by practical assessments. The intention was to quantify the differences between the curves as a basis for photographic testing. I could repeat for greater precision but it would be more to satisfy my curiosity than for practical needs. I should say that the curves were not merely extrapolations, as I think Bill implied. I did try to fit a mathematical curve to them, but all were a poor fit.

Simon Denny June 23rd, 2009 09:22 PM

I read that the BBC recommend Cine 3 for best over all shooting. I found this on their web page for the EX1,3 settings.

Alister Chapman June 24th, 2009 12:52 AM

The BBC recommendation is interesting as it implies several things. One is that all footage will be graded as Cine 3 will produce illegal levels and somewhat washed out blacks (in a gradable way). The issue that the BBC have when making such recommendations is that they are looking for a general purpose setting that will work for most applications. This doesn't mean it's always the best setting. I would have recommended a standard gamma ( 2 or 3) with a fixed knee at 85 as this will work for most shoots without producing illegal levels.

The problem with just using the cinegammas without grading is that while it might look nice in your edit, if your programme then goes through any kind of limiter or legaliser the highlights get chopped off. So anything broadcast stands to look a lot worse than when it was shot if the material is not carefully graded or legalised.

There is no right or wrong gamma to use, it will depend on your own specific requirements, the look you are trying to achieve and your workflow. The only gamma I will never use is standard gamma 1 as it is very noisy and never use cinegamma 2 at -3db as it gets clipped at 94% restricting lattitude.

Simon Wyndham June 24th, 2009 01:34 AM

Quote:

The issue that the BBC have when making such recommendations is that they are looking for a general purpose setting that will work for most applications.
Depends which document this was from. If it was from Alan Roberts documentation then generally he was after the best result for grading and 'film look'. For general use, as you say, STD gamma 3 with the set knee is the best option, and the reason why this is the default setting, although STD gamma 4 is also a good option if you wish to stay in that realm but want more scope for a grade afterwards.

I'm tending to use Cine 1 a lot for my outdoor shots now. It gives great results when combined with Tiffen DFX.

Piotr Wozniacki June 24th, 2009 01:47 AM

I think it's important to mention that when delivery is only planned to the computer screen or BD, those values recorded above 100% which would be illegal in broadcast or SD DVD are completely OK, and can contain information that can be displayed without clipping.

Therefore, I'm basically using 4 PP's, based on the following gamma curves:

- Cine1 for bright outdoor scenes without backlight (clear sky)
- Cine4 for dull outdoor scenes with strong backligh (like from white cloudy sky)
- Std1 for low contrast indoor scenes, with low light but without backlight
- Std4 for low light indoor scenes with backlight

I'm using Std gammas for lowlight indoors mainly because the overall brightess they yield is substantially higher than that of Cine gammas.


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