View Full Version : Black Gamma and Noise.


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Paul Kellett
January 1st, 2009, 07:14 AM
Page 75 of the manual.
Black Gamma

-99 to +99

Adjust the level of black gamma function that emphasizes only the dark areas of the picture to clear the tones or on the contrary de-emphasizes it to reduce noise.


So does this do the same as crispening to reduce noise ?
I'm trying to reduce noise in the blacks for when i shoot in low light.

Paul.

Alister Chapman
January 1st, 2009, 07:48 AM
Black gamma adjusts the bottom of the gamma curve up and down, in effect stretching or compressing the darker parts of the image. By using a + setting you can make dark areas of the image brighter which lifts those areas up out of the noise that can effect the darker parts of the picture. However if you bring the black gamma up too high you loose contrast and can end up with your darks raised so high that it is very difficult to get any detail in the darks and the image doesn't look good.

Paul Kellett
January 1st, 2009, 07:57 AM
So adding black gamma reduces noise by "brightening" the blacks ?
I thought that would add noise, like having the effect of adding more gain to the blacks.

Ideally, for when i'm shooting in low light, maybe wedding receptions/disco's i'd like to add gain but not so much in the blacks, can't see much detail in dark jackets anyway or outside in dark skies.

I've played with the crispening but it doesn't seem to do much.

I'm happy with the pp i use but just want to lower the noise a bit when using the gain, i do go up as high as +12db sometimes.

Thanks for the explanation Alistair.

Paul.

Bill Ravens
January 1st, 2009, 08:00 AM
Once things sink too deeply into the blacks, overall s/n gets overwhelmed by "n" (noise) The dark current of the sensor produces noise where no image exists. The idea, here, is to raise the shadows above the sensors idle/spontaneous noise level. Raise the shadows too much, however, and you get mud.

Steve Phillipps
January 1st, 2009, 08:04 AM
You guys want to be careful when altering these settings, really should be left to an expert, as tech guys have all sorts of measuring equipment that lets them know exactly what's going on. I'm very cautious when changing anything, just because it looks good on your particular monitor doesn't mean it will on anything, especially broadcast where you might find things have gone very wrong.
Steve

Bob Grant
January 1st, 2009, 03:17 PM
Maybe I'm missing something here but I would have thought increasing black gamma will increase noise. You are adding gain at the bottom end of the curve where S/N is at its lowest. The dark current noise of the sensor is fixed by physics, not much can be done about it apart from cooling the camera.
On the other hand decreasing black gamma will crush the blacks and that's certainly not a look I'm fond of. However if shooting in low light with the gain up reducing the noise going into the encoder may yield benefits that outweigh the look of crushed blacks.

Alister Chapman
January 1st, 2009, 03:30 PM
I've been thinking about this one and I need to go have a look at what actually happens. Certainly increasing gain will increase noise. I may have to eat my words!

Paul Frederick
January 1st, 2009, 05:21 PM
This was recently posted in another thread...great info that may be of help. It explains crispening and black gamma quite well.

Sony | Micro Site - XDCAM EX (http://pro.sony.com/bbsc/ssr/micro-xdcamexsite/resource.latest.bbsccms-assets-micro-xdcamex-latest-ShootingTipsIndex.shtml)

Paul Kellett
January 1st, 2009, 05:58 PM
I've been thinking about this one and I need to go have a look at what actually happens. Certainly increasing gain will increase noise. I may have to eat my words!

I did have a play with black gamma today.
Lowering (-) the black gamma did make the blacks blacker, as expected, sort of like lowering the normal black, it also appeared to lessen the noise in very dark areas.
I experimented in a room in my house, curtains shut, light off, 12db gain, although i looked on my camera screen, i haven't got a posh monitor.

If i'm shooting a wedding reception and i need to add gain then i can live with the blackest things staying black if it means no noise in those areas, ie black/dark dinner jackets, shadows under tables, dark hair etc.

If i'm reading the EX1 manual correctly then this is what the black gamma effects.


Thanks to everyone for chipping in, if we can come up with a less noisey PP for dark scenes
then i think we'd all be happy.

Thanks.
Paul.

Bill Ravens
January 1st, 2009, 07:44 PM
it may be the case, and i just don't know for sure, that black gamma works more like a noise gate, setting it lower effectively shuts the door on any kind of signal, be it noise or not. Worst thing about these nebulous descriptions we get from Sony, who knows?

Greg Boston
January 1st, 2009, 11:11 PM
it may be the case, and i just don't know for sure, that black gamma works more like a noise gate, setting it lower effectively shuts the door on any kind of signal, be it noise or not. Worst thing about these nebulous descriptions we get from Sony, who knows?

Black Gamma is analogous to Black Stretch/Compress on other cameras. It is altering the shape of the bottom of the gamma curve.

-gb-

Piotr Wozniacki
January 2nd, 2009, 02:40 AM
Black Gamma is analogous to Black Stretch/Compress on other cameras. It is altering the shape of the bottom of the gamma curve.

-gb-

I agree with Greg, and compressing blacks has always been my preferred method of getting rid of some dark areas' noise (along with detail, of course - but I like that look, especially in low-light scenery; it's more "filmic" to me).

Bob Grant
January 2nd, 2009, 03:32 AM
What I think does work like a gate is "Black". From the description this is the same as what is known as Master Pedestal.
Anything above the Black level is then affected by Black Gamma.
Anything below the Black level is clamped to black.

The manual seems to recommend two adjustments to reduce noise. Black Gamma and Low Key Sat.

Atilio Menendez
January 2nd, 2009, 09:41 AM
Not only the black gamma is important here, also the general gamma curve.
Paul, which gamma curve are you using? I would recommend cine4. I think that using a "brighter" gamma curve is better than using a darker one (such as cine1) and applying gain to it. The camera achieves the brighter image on cine4 by applying gain in a non-linear fashion. It applies progressively less gain as it gets to higher values and thus protects your highlights from clipping. If you use cine1 and apply gain, gain is applied equally to all brightness values, thus clipping more of your highlights.

Paul Kellett
January 2nd, 2009, 10:41 AM
I'm using STD 1, hi sat, i like the punchier colours i get.

Paul.

Wayne Zebzda
February 28th, 2009, 02:35 AM
I will be shooting a reflective suit made of 3m products (ths very same substance on traffic signs) . The hope is for the suit to look like a 2 dimentional object running down the middle of the road, like flat pixels, tiny squares flatly moving like computer animation in the dark . I would like the lowest noise possible in the darks and have one evening to shoot with my film permit. The reflective material shoots back all the light to the source which is a camera and car head lights.
I will post the results but would appreciate any picture tweaking you think might help
Thanks (Mahalo),
Wayne Z

Alister Chapman
February 28th, 2009, 03:26 AM
I have been looking very closely at the EX noise levels and what can be done with the PP to minimise the noise.

My first and perhaps most significant discovery is that the different STD and Gamma curves all have very different noise levels. The worst is STD1 which is much, much noisier than any of the other Gammas. I found CineGamma 1 to have the least noise.

From what I can tell the camera applies gain after the gamma curve. This has a bearing on the peak white levels and black levels that are recorded. As the gain is increased so is the recorded white clip level, so with gain above 0db it is very easy to record illegal levels.

The Black level setting effects the pedestal. I have found on both my EX1 and EX3 setting black to -4 at 0db gives no pedestal (measured with a scope). You might want to use -3 to be sure of not clipping any blacks.

Crisping sets the level at which detail correction is applied to the image. My trials indicate that increasing the crispening to a positive value makes the camera apply less detail correction to low contrast areas of the image. From my experiments I have decided that a value of +20 to +30 helps control noise in darker areas. It's not a massive difference but it does help.

Detail Frequency changes the width of the detail correction that is applied to the image. Remember that the camera is not clever enough to differentiate between noise and true image detail so detail correction gets applied to both. Personally I prefer to increase the detail frequency to make the edges thinner, this make the noise less obvious and gives a less processed looking image. However you have to be careful as go to high (thin) and you will get twitter, aliasing and stress the codec. I use Frequency at +30 to +40.

Now with the above settings the picture is already looking a little softer, but it is still just a little too sharp for me so I run the Detail at -8 to -10 just to take the edge off.

I don't use black stretch, but Increasing it to a positive value can help if you have large areas shadows but this also brings up the noise levels in dark areas.

Further improvements can be gain by using the Low Key sat control to reduce the chroma saturation in dark parts of the image. Again it's not a big difference but it helps if you run it at -15 it helps control saturation noise in dark images.

While I was looking at all these setting I also noticed that if you use the CineGammas with the STD or HISAT matrix you get a slightly odd colour response curve, this may be contributing to the IR problems, but needs further investigation to confirm. Whatever it seems that using the STD or HISAT matrix with the CineGammas gives some very uneven colour response with big peaks at certain wavelenghths, in particular reds. I found that by using the Cinema Matrix I get a much flatter and more natural response, however the image is much less saturated. So for a natural look with CineGammas I am using Cinema Matrix at +35.

So if you set up a profile using
CineGamma 1
Black -4
Detail -8
Crispening +20
Frequency +30
Cinema Matrix at +35

and then compare that to Standard setting 1 you will see a massive difference in noise. Additionally as CineGamma 1 records to about 109IRE if you use -3db gain you will get a further reduction in noise and also now only have levels going up to 104IRE.

The trade off of this PP is that the overall sensitivity of the camera is reduced by about 1.5 stops over standard. Even if you then apply 6db gain you still have a clean picture. If you need a setup for low light try the above settings but with STD Gamma 4 or CineGamma 4.

Please not that these are just my findings and are not necessarily based on science! But they do seem to work.

Paul Kellett
February 28th, 2009, 06:38 AM
I don't use black stretch, but Increasing it to a positive value can help if you have large areas shadows but this also brings up the noise levels in dark areas.

.


Very informative Alistair, thanks for posting.
When you say black stretch, i presume you mean black gamma yes ?

Thanks.
Paul.

Alister Chapman
February 28th, 2009, 07:37 AM
Sorry, yes black gamma. It has the same effect as black stretch.

Piotr Wozniacki
February 28th, 2009, 07:59 AM
Finally, Alister's confirmed with his insightful post that what I've been doing since the beginning isn't wrong - namely, using Cinema color matrix, rather then Hisat, especially in conjunction with Cine gammas.

Cranked up a little (like Alister's +35), it's always looked better to me than using Hisat color matrix with individual pairs convoluted to fight the dominating Red channel (and I have seen people using PP's with R-G as low as -75 or as high as +75). Sorry, Bill ;-)

Alister Chapman
February 28th, 2009, 08:33 AM
I spent quite a while with a really good 52" monitor (proper monitor, not a TV) and a waveform monitor looking at various settings. I had not really realised before just how uneven and inaccurate chroma response with the CineGammas and both Standard and HiSat matrices is. There is a really big and quite narrow peak in the reds and I do wonder if this is what makes the IR issue so pronounced. As I said this needs to be investigated further. I've never really used the Cinema Matrix as it has always looked very under saturated, but it was almost out of desperation, trying to get a flat chroma response with the CineGammas that I tried it once again. The difference is quite dramatic to say the least. I'm really pleased with these settings as I now have what I regard as a good starting point for any "looks" that I may want to brew using the individual matrix settings.
It started out as an investigation in to reducing noise, which it does quite dramatically compared to the factory default, but I have also found a really pleasing and I think very natural look.

I would be interested to see the results of the BBC's noise evaluation with these settings. The other thing to remember is less noise means less stress on the codec which is always a good thing.

Again I'm more than happy to share my findings, just don't take this as the only way to do things, just a suggestion based on a little (well a lot) of experimentation.

Wayne Zebzda
February 28th, 2009, 01:30 PM
Many thanks Alister!

Wayne Z

Juan McFarland
March 2nd, 2009, 07:00 AM
Alister, thank you for taking the time to post your findings and explain them as well. I'm looking forward to trying them out.

In regard to gain structure and recording latitude I have questions and observations related to your findings:
You reported less noise with the minus 3db setting. Based on theory (correct me if I'm wrong -it's usually the case!), signal to noise ratio of the sensors is not improved by lowering the sensor output. A gain reduction will reduce noise, but you also get less signal, the end result is the same amount of noise relative to the signal (although some of that noise may now be crushed into the blacks, so that noise is gone since that part of the image is now black, so in a way I guess this does reduce noise!). You found that the using Cine 1 and -3db had the camera clipping at about 104 IRE*. IF the noise reduction improvement using this scenario is resulting from the noise in the dark areas of the image being hidden in the blacks would it be better to shoot at 0db to maintain maximum (109 IRE) latitude and either compress the black gamma or crush the blacks? This method of preserving maximum latitude up to 109 IRE seems to make more sense to me.

That said:
Do you think the EX1/3 sensors are calibrated to zero db in relation to the 0db gain display indicator, Or did the Sony engineers cheat a bit to make the camera seem faster than it actually is by amplifying the sensor output and claiming the amplified level as "zero" db? This would explain improved s/n ratios at negative gain settings.


And finally, some interesting observations of clip levels relative to combinations of camera gain and gamma settings.

*When minus 3db gain is selected I noticed that only Cine 1 makes the camera clip at 104 IRE.


Observed clipping levels using Cine and Standard gamma settings when -3db is used as follows:

Cine gamma 1 clips at 104 ire (based on Alister's finding using a waveform, and my observations of the lowered histogram graph)
Cine gamma 2 clips at 100 ire (based on this being the 'broadcast safe setting' and my observation of an even lower histogram graph)
Cine gamma 3 clips at 101-103 ire (I'm estimating because I'm using the histogram, no waveform scope available. Histogram graph is maxing out between the 100 and 104 readings previously established.)
Cine gamma 4 clips at 101-103 ire (I'm estimating because I'm using the histogram, no waveform scope available. Histogram graph is maxing out between the 100 and 104 readings previously established.)
Standard gamma settings 1 through 4, (interesting!) all the Standard Gamma settings clip at 109 ire when the camera is -3db!!

Alister Chapman
March 3rd, 2009, 04:11 PM
Just quickly as I'm between shoots..

-3d gives less noise and you are correct also less output, but you can compensate for less output by opening up the iris, which does not add noise, that improves the signal to noise.

Cinegamma 2 at -3db limits at 96IRE so you loose headroom.

Keith Moreau
March 3rd, 2009, 04:39 PM
Alister, thanks for the great information you've presented here, I'm going to try to digest it and implement it when I have a chance.

I've found that the -3db gain setting reduces the headroom as is indicated on the histogram for most picture profiles. There is a 'brick wall' on the right side with -3db set.

If I can't increase the output level beyond the brick wall it's hard for me to understand how making the EX1 clip at lower levels will would decrease the noise as well, it seems it would have the opposite effect. I've been using the 0db setting for shooting for a while since I realized this and though I haven't done any scientific tests I'm pretty happy with the footage and the increased latitude I get.

Alister Chapman
March 4th, 2009, 03:36 AM
The headroom brick wall exists with any of the Gammas, standard or Cine. You have to remember that anything above 100IRE is not "legal". That is to say that when video that goes above 100% is broadcast, encoded or put on a DVD it may simply get clipped at 100% so any extra information may be lost. Now, how bad that is will depend on the software you encode with, how it behaves above 100IRE, the broadcast chain, the codec, the DVD player, the monitor and many many other things. You might get away with it, or you might not. Best practice is to keep your peak white level at or below 100IRE. So while at first glance you may have more latitude it really depends on how you will work with the material in the post production chain.

Any noise is going to be most apparent in the darker parts of the image. If you can swamp the noise by bring the video brightness above the noise floor then your picture will be cleaner. By reducing the gain to -3db you reduce the noise level and thus make it easier to swamp the noise by opening up the iris to increase the amount of light coming in relative to the noise signal. The small loss of latitude or headroom is not going to make much difference as the top end of the Gamma curve is compressed anyway, either through the use of a knee or Cinegamma. Most of your noise is at lower levels which have higher gain due to the way the gammas work.

If as you say you can't see how reducing the gain can give a reduction in noise look at it the other way. As you increase gain you will see an increase in noise. A like for like correctly exposed shot at +9db gain will be very noisy while a 0db gain shot will not.

Mark Twittey
March 4th, 2009, 07:31 AM
G'day Alister,
I have just ried your PP settings on a small shoot this week, It is very nice very natural looking pictures, not over saturated.
Could you confirm with that PP, what the other settings are?
Colour Correction, Offset White, Black Gamma e.t.c.
Thanks

Keith Moreau
March 4th, 2009, 10:39 AM
The headroom brick wall exists with any of the Gammas, standard or Cine. You have to remember that anything above 100IRE is not "legal". That is to say that when video that goes above 100% is broadcast, encoded or put on a DVD it may simply get clipped at 100% so any extra information may be lost. Now, how bad that is will depend on the software you encode with, how it behaves above 100IRE, the broadcast chain, the codec, the DVD player, the monitor and many many other things. You might get away with it, or you might not. Best practice is to keep your peak white level at or below 100IRE. So while at first glance you may have more latitude it really depends on how you will work with the material in the post production chain.

Any noise is going to be most apparent in the darker parts of the image. If you can swamp the noise by bring the video brightness above the noise floor then your picture will be cleaner. By reducing the gain to -3db you reduce the noise level and thus make it easier to swamp the noise by opening up the iris to increase the amount of light coming in relative to the noise signal. The small loss of latitude or headroom is not going to make much difference as the top end of the Gamma curve is compressed anyway, either through the use of a knee or Cinegamma. Most of your noise is at lower levels which have higher gain due to the way the gammas work.

If as you say you can't see how reducing the gain can give a reduction in noise look at it the other way. As you increase gain you will see an increase in noise. A like for like correctly exposed shot at +9db gain will be very noisy while a 0db gain shot will not.

Thanks for taking the time to reply here. I've observed the brick wall in the histogram to not be present for some PP settings with -3db gain, present in others. I'm actually an electronics engineer so I'm pretty well versed in gain vs signal to noise ratio and I believe your statement about additional positive gain also raising the noise floor (as well as the signal level) is correct, although I'm debating whether negative gain (-3db) will reduce the noise relative to the signal level. My intuition and training suggests that negative gain will reduce the noise floor but also the desired low level signals along with it, for example by adding attenuation to a signal prior to being processed further, which doesn't help reduce the noise floor relative to desired signal.

I also agree that the extra headroom afforded by the 0db setting adds headroom in the non-legal areas of the signal, however since I'm color correcting the signal if necessary to reduce non-legal whites I feel the 0db gain gives me more latitude and choices.

Using the camera's histogram as an example there is also a 'brick wall' on the left side, similar to the right side when using -3b gain. That brick wall doesn't seem to go away for any reason with different PP or gain settings, but the right brick wall does go away with 0db gain settings.

Of course all my theory and instinct becomes irrelevant if the EX's terminology or use of the term 'gain' has a different meaning. Like is '0db' gain labels in the camera are in fact electrically +3db and -3db gain is in fact 'no gain' electrically. I guess actual scientific tests of the noise levels at -3db vs 0db would end the debate and I apologize if this has already taken place previously for the EX camcorders.

Thanks again for your time Alister, this is all very helpful and interesting.

Bill Ravens
March 4th, 2009, 11:18 AM
Good post, Keith. I agree. Reducing gain, typically, drops the signal level without dropping the noise level, which is really a function of the fixed "dark current" of the detector.

I've observed that I CAN move the left hand "brick wall" in the histogram by adjusting the black level.

Alister Chapman
March 4th, 2009, 05:14 PM
Lets look at it a different way. As Bill says the bulk of the noise comes from the sensors dark current . The gain setting controls the amplifiers that amplify the output of the sensors. They are set with a nominal 0db point where the best balance between noise, linear output and dynamic range is thought to be. Assuming 0db actually means no amplification then -3db means attenuation of the sensors output by 3db. If we take the output from the sensor and attenuate it by 3db we will reduce everything, reduce the noise by 3db and reduce the output signal by 3db. However we can increase the output signal of the sensor by increasing the amount of light falling on the sensor simply by opening the iris. Opening the iris is a linear function so even the amount of light in dark areas will be increased, the entire image will be made brighter by opening the iris. Thus the signal to noise is improved as for the same output we are attenuating the noise by 3db. So where you have enough light in hand to reach the desired exposure you can get a better S/N ratio by using negative gain or attenuation of the sensors output. Even if -3db gain is not actually an attenuation, but simply 3db less gain than there is at 0db the same applies, there will be 3db less noise.

I would agree that 0db gives the best dynamic range, but you do have some serious over shoots into illegal levels to deal with in the edit. Given the slightly reduce headroom (but still over 100%) levels with -3db gain and Cinegammas 1,3 and 4 I don't think that the tiny bit of extra lattitude (quarter of a stop perhaps) will always be preferable to less noise. Noise is difficult to get rid of once it's there and a "clean" image will grade better and withstand post production better than a noisy signal. As I have said there is no "right way" or "wrong way" to apply the gammas and gain and different settings will work for different situations.

You can adjust the black level, but you are not adjusting the gain or sensitivity, just changing the level at which the blacks are clipped. Raising the black level will simply raise the raise the brightness of the darkest level that can be recorded. Other than for setting the pedestal correctly I can't really see a great deal of use for the Black Level setting.

Mark: all the other PP settings are at factory default. Glad you like the look.

Keith Moreau
March 5th, 2009, 05:54 PM
Alister, thanks for taking the time for the explanation,. I think it makes sense to me now. I also do audio and your explanation is akin to turning up your electric guitar as hot as you can and then reducing the signal down at the mixing console, the noise floor is reduced. I guess if you want to keep your recorded levels below what is possible then the brick wall is ok and you don't have to deal with superwhites in post.

Do we all know scientifically for a fact that -3db actually results in lower noise for a given signal level, up to the point where it hits the brick wall other than the assumptions about what is going on with -3db vs 0db?

Bill, I've tried adjusting the black level but no matter what I do I can't get the left side brick wall to go away, I can get it to move the wall to the right but not all the way to the left.

Thanks all again for the good info.

Alister Chapman
March 6th, 2009, 01:32 AM
I can see the differences in noise in my images between 0db and -3db.

Michael Maier
April 19th, 2009, 10:25 AM
Crisping sets the level at which detail correction is applied to the image. My trials indicate that increasing the crispening to a positive value makes the camera apply less detail correction to low contrast areas of the image. From my experiments I have decided that a value of +20 to +30 helps control noise in darker areas. It's not a massive difference but it does help.

Interesting findings, specially given the BBC tests produced very different recommendations. The BBC tests recommend a crispening setting of -45. What’s your opinion on that Alister?


By the way, any new findings on the cinema matrix use?

Also, when you use the matrix set to cinema, do you use all factory default settings for Level, Phase and color settings (R-G, R-B, G-R etc) or do you use Bill’s TC3?

Thanks.

Simon Wyndham
April 21st, 2009, 01:29 PM
The BBC tests recommend a crispening setting of -45.

There is a big difference in aims between what Alister is aiming for in his PP and what Alan Roberts was. Roberts is aiming for as close to a scientific replication of the way film handles detail.

You will notice that Alan reduces the detail right down, so the crispening gives some compensation to this. It would be more useful if the EX included a Level Depend setting.

One thing to be careful of with the cinegammas is shooting interview shots. Better to use STD gammas for such shots since the cines can compress those tones in a not very nice manner. I prefer Cine 4 out of all of them.

Michael Maier
April 21st, 2009, 04:29 PM
There is a big difference in aims between what Alister is aiming for in his PP and what Alan Roberts was. Roberts is aiming for as close to a scientific replication of the way film handles detail.

You will notice that Alan reduces the detail right down, so the crispening gives some compensation to this. It would be more useful if the EX included a Level Depend setting.


Hi Simon. Not really sure I understand what you mean above.

One thing to be careful of with the cinegammas is shooting interview shots. Better to use STD gammas for such shots since the cines can compress those tones in a not very nice manner. I prefer Cine 4 out of all of them.

Cine4 if you would "have" to shoot an interview with a cinegamma or for general use? I find Cine1 to be best in handling high contrast scenarios like day externals with shadows than Cine4. I like Cine 4 for low light.

Michael Maier
May 3rd, 2009, 02:42 AM
Hi Simon, I'm still interested in your reply :)

Alister Chapman
May 4th, 2009, 02:47 AM
I can't work out why Alan suggests setting crispening to -45. It increases noise in the shadows. I know Alan did not spend a large amount of time with the camera and didn't find many things such as the difference in cinegamma peak levels at different gain settings and differences in noise with different gammas.

With all these settings there is no right or wrong way to set the camera up. Different people and different projects will have different needs and want different things from the camera. For many years European broadcast cameras were set up according to a setting called EBU75, developed by the BBC and EBU. The whole idea behind this setting was not to get the best out of the camera, but to provide a setting that restricted the gamut to a level that could be displayed on even the cheapest of CRT TV sets without any artifacts. Sadly the BBC's standard HD setup is still largely based on the old EBU75 setup, restricting the colour range to around 75% of what is perfectly legal for broadcast.

I almost always use the cinema matrix at +30 as at 0 the chroma levels are way down.

I also completely agree with Simon about not using cinegammas for interviews as even the slightest over exposure of skin tones will not look natural.

Serena Steuart
May 4th, 2009, 03:00 AM
Crispening affects the lower luminance regions of the image where you find noise.Giving it a positive value ensures that detail isn't applied to noise, and the higher the value the higher the threshhold at which sharpening is applied. To quote Sony:
"Crispening is a function that prevents detail signals being generated around noise or small picture edge transitions, when the DETAIL function is set on. This allows you to select the threshhold (based on transition level) of picture edge transitions to which detail signals should not be added. "

Michael Maier
May 4th, 2009, 04:01 AM
Makes sense Alister.
Maybe the BBC setting is a typo and he really meant +45?
Maybe somebody who knows him should ask. If it's a typo it needs to be corrected. Noise is a big thing.

Although I tend to agree with the BBC settings in using the cinema matrix if you are shooting drama or want to emulate film or are going to filmout. The normal matrix is too saturated for that, looks more like TV in most cases.

Simon Wyndham
May 4th, 2009, 04:25 PM
Crispening affects the lower luminance regions of the image where you find noise.Giving it a positive value ensures that detail isn't applied to noise, and the higher the value the higher the threshhold at which sharpening is applied.

No. Crispening affects the whole image. The Level Depend function that I mentioned earlier that appears on higher priced cameras would enable tuning of the luminance level at which detail is applied.

I can't work out why Alan suggests setting crispening to -45. It increases noise in the shadows.

True, very true. But I think the reason is that Alan doesn't aim to perform functions such as reducing noise. He actually aims for the opposite, to eliminate as much as he can the electronic processing while using some functions to subtly get the result he wants. *However* like Alister I do not always agree with the settings that Alan comes up with. He rarely gets the time he needs to do these setups with any degree of fine tuning, by his own admission.

David C. Williams
May 4th, 2009, 05:30 PM
http://pro.sony.com/bbsccms/assets/files/micro/xdcamex/solutions/Improving_Picture_Sharpness.pdf

Not specifically the EX, but Sony jargon stays fairly consistent.

Serena Steuart
May 4th, 2009, 07:10 PM
No. Crispening affects the whole image.

Gosh, Sony don't understand their crispening function!

Simon Wyndham
May 5th, 2009, 03:05 AM
Gosh, Sony don't understand their crispening function!

No, they understand it perfectly. Read again the quote you gave from the Sony description
"This allows you to select the threshhold (based on transition level) of picture edge transitions to which detail signals should not be added."

That description is not talking about luminance levels, but edge frequency. The crispening function tunes the point at which the detail circuits kick in. By tuning the crispening you can fine tune things to make sure that the camera is not applying any detail correction to the noise in the picture at all levels of luminance.

The Level Depend adjustment found on cameras like the PDW-700, 510, 530 etc allows you to adjust the luminance level at which the detail correction kicks.

The function is explained here http://pro.sony.com/bbsccms/assets/files/micro/xdcamex/solutions/Shoot_without_Course_Dark_Areas.pdf

Serena Steuart
May 5th, 2009, 03:48 AM
Ok!............

Bob Grant
May 5th, 2009, 06:03 AM
Would not the Black Limiter setting in Detail achieve what you're looking for?

Paul Kellett
May 5th, 2009, 07:30 AM
What exactly does the black limiter do ? And the white limiter for that matter.
Can you explain it in plain english please.

Thanks.
Paul.

Alister Chapman
May 5th, 2009, 02:31 PM
I believe the Black/White limiters limit the luma level of the applied detail correction edges.

Crispening works on the levels within the image not frequency. So you can choose to not apply detail correction to small picture level changes while still adding enhancement to larger changes. As noise is generally a small change in level you can use crispening to prevent detail being applied to the noise.

Serena Steuart
May 6th, 2009, 05:36 PM
Crispening, as I understand it, is described here: http://pro.sony.com/bbsccms/assets/files/micro/xdcamex/solutions/Improving_Picture_Sharpness.pdf

Christopher Barry
May 8th, 2009, 05:33 AM
So if you set up a profile using
CineGamma 1
Black -4
Detail -8
Crispening +20
Frequency +30
Cinema Matrix at +35



Could you confirm with that PP, what the other settings are?
Colour Correction, Offset White, Black Gamma e.t.c.


Also, when you use the matrix set to cinema, do you use all factory default settings for Level, Phase and color settings (R-G, R-B, G-R etc) or do you use Bill’s TC3?

Alister, if you don't mind sharing, would you kindly provide us with the complete PP settings you are using? I can see that changing the matrix from Hisat to Cinema may, for example, require the R-G, R-B, G-R values to vary from, say, Bill's TC3 PP.

Alister and all contributors to this thread, thank you.

Michael Maier
May 10th, 2009, 09:40 AM
I second that question.