Si2k and greenscreen

[Peter Moretti]

Bob, good luck with this and I'm very curious to find out how the key went.

It looks to me like the car could have been lit more brightly, and a little less warm. Sometimes it's a good idea to be sure the talent's hair is a little more under control, e.g. girl with the dirty blonde hair.

But I think you should definitely be able to get a good key out it. And I think having a moving background may make selling the key easier, although you will have to match color temps and pobably lighten some areas on the talents' face. Just a guess.

Thanks very much for sharing, and if you get a chance, let us know how it all turned out ;).

[Bob Hart]

Peter.


I think it was that I did not have the half CTO gel for the 1.2K HMI.

I believe there is also a style thing happening. I think the backgrounds are to be oversaturated and contrasted. Power resources were also very limited in the shed we were using as a studio.

I'm trusting my DOP. He has about 30 years of film lighting experience in 35mm commercials in AU and offshore in Singapore and Jakarta. He tells me there is a technique called green suppression which he has seen used in similar circumstances for commercials.

On a previous shoot, he created stuff out of the available light I was already set to give up on.

Girl with dirty blonde hair? The young guy might be a little concerned about that observation.

[Peter Moretti]

Hey Bob,

If that's not a girl in left of the second still you posted (post #6) then I've become too old for this business, LOL! :)

[Alex Raskin]

The boy is dirty blonde.

The girl is clearly blonde.

[Bob Hart]

No clean or dirty female blonds in there. The two fairheadeds are Cameron and David, both minors playing the parts of crimmy teenagers on their way to juvenile court, so no last names without parental consents.

You have it correctly Peter and they say that making movies is ageless. Lisa Bennet has the dark hair. She is a true professional and very committed, enquires in detail about her role and the backstory behind her character, then "owns" the character entirely.

[Kaspar Kallas]

Hi

1. Is this V1.1 or V2.0 - big difference in compression quality. Judging from the stills it should be quite easy key in compositing, not one click thing but nothing really complicated in nuke for example. Just make sure You use advanced detail2 debayering, or do sharpening in Your compositing software.

2. -3dB does NOT make less grain, it just limits the highlights never reaching 100% so it actually just clips dynamic range - not good for anything that I know....

3. If you are shooting things slightly underexposed (lots of dark areas in the image) it is actually better to shoot +3 to +6 to get clearer image, but should not necessity in this case.

My soon to be 2 euro cents
-Kaspar

[Alex Raskin]

Kaspar: >> -3dB does NOT make less grain, it just limits the highlights never reaching 100% so it actually just clips dynamic range

Are you sure? How can decreased gain value work as a limiter?

Also, I do remember doing a (not scientific) test a year ago when I first got my SI2K, and it appeared that -3dB gain setting was a bit cleaner than 0dB. I'm referring to the amount of digital noise. Don't know what "grain" corresponds to in digital realm.

It'd be great if Ari chimed in on this.

[Bob Hart]

Kaspar.


Thanks for your advice.

As a user of DVR2.0, could you tell me if it records only to ".mov" files. I could not find ".avi" files in the beta demo version.


To everyone, another question.

I tried fitting a SSD into a dataport ( digital magazine ). The P+S recorder unit does not see the SSD. My XP computer does see it in the dataport. I have a dataport dock on the computer.

I then initialised and formatted the SSD in my XP computer to NTFS. I copied a project file and camera file across to it, then put it back into the P+S recorder unit. The P+S recorder unit still does not see the SSD.

Any advice on what I am doing wrong will be greatly appreciated.

[Kaspar Kallas]

Hi

1. The gain/grain issue - this is analogue gain - the actual voltage on the sensor is changed. So this does not work as as it does on majority of video cameras and even RED and Arri, where the digital data is scaled. Because all sensors are linear that means 1/2 of the bits are used to see the brightest stop of the image, the next stop is 1/2 of the remaining bits and so forth. The noise in all of it is uniform. So when you start to gamma the image from linear you will gain the lower stops by power function therefore you scale up the noise. So the more underexposed your image is, the more noise you will manage to "pull up".
Now there is different base noise is the sensor but when image is properly exposed you still see very little of it.
About -3DB just do a simple test, shoot something overexposed and measure the digital value of the pixel. Because the voltage is lower the pixel will never achieve full saturation but it will be flat grey, not more image information.

For shooting in really dark circumstances it helps to actually gain the camera up to get cleaner image. For example the Werner Herzog's "Cave of Forgotten Dreams" everything inside the cave is shot with +6db because we had only 3 led light-panels that were allowed to be used.

2. DVR is MOV only, not a problem fro me because I have used MOV as long as it has been an option.

3. I dont know almost anything about PS bodies, I have built my own recorders mostly - yet this year I was working on feature in Argentina that had hired one - I really was not impressed, it was v1 and had only USB connection the HDD. It didn't handle humidity as well, even worse than Arri D20.

Thank You
-Kaspar

[Bob Hart]

Kaspar.


Thanks for the info.


1. Thanks for the info on -3db. Gavan O'Sullivan, who DPed was metering with the spotmeter and colour temp meter he normally uses on film.

Also, as I mentioned, he treated the SI2K as a film camera. His exposures were a bit hotter than I have been using but they all look better than my own, which verifies your suggestions.


2. I am a bit sad about losing native .avi files in DVR2.0. It means going through a conversion step for work on Windows PCs instead of editing from the camera files. This direct workflow was the competitive attraction we had over the RED for Windows PC.

I concede more clients asking for the SI2K were editing on FCP or AVID than on PCs, so native camera-original .mov files which can be pulled straight into FCP are likely more competitve.

I guess SI and P+S must have researched and found more work is done on macs with .mov files than with .avi files on Windows PCs. We may shoot on DVR1.681 for clients who are on WindowsPC and use DVR2.0 for Mac clients.


3. We have the later version of the P+S camera bodies. These have SATA to the D:\> drive.

As for laptop computers, we have not had a lot of luck yet getting them to work reliably as recorders. We are still using DVR1.681. What laptop have you found to be reliable in real-world conditions?

[Alex Raskin]

Kaspar, what you said about SI2K noise. What is the bottom line. Do you recommend shooting at 0dB setting, because you say this does not increase noise but provides correct gamma/latitude throughout the brightness range?

What noise are we talking about - does your 0dB example include noise in the dark areas of the image, which you say won't be affected negatively by increasing gain from -3dB to 0dB?

Bob, mov's should not be an issue on PCs. What are you guys editing with. Adobe Premiere CS5 takes virtually anything and converts it into its own intermediate format, internally, on-the-fly. That includes mov's. I did not work with Cineform mov's in CS5, but all others were imported just fine.

Regarding external drive, while SSDs seem attractive, they don't seem to work reliably as external storage with SI2K/SiliconDVR. Both I and Justin Lovell reported the same issues (we use custom laptops, actually): SSD drive would randomly get data corrupted. In my case, audio started lagging behind the video - a lot, and variably throughout short (10min) clips! This never happens with HDDs, so just stay with them.

HDD vs SSD: latter wins on speed of data transfer, and because it is not susceptible to vibrations and thus can be used in rough environments like running with cam etc.

However, all CFHD needs (due to low data bandwidth) is a 5400rpm drive, so speed is not an issue here. And with the second advantage, you'd have to have your OS drive to be SSD as well - which apparently you don't.

Why SSD then?

[Bob Hart]

"What are you guys editing with?" -- Bob sheepishly looks away and replies very quietly so no one else can overhear, "Premiere Pro 2/Prospect2KV3".

"Why SSD then?" -- Bob sheepishly looks away in the other direction - "Thought I would get ablity to record longer bursts of uncompressed when needed but mainly to be able to switch out of adaptive mode".

If somebody had cobbled together a RAID array out of 50 CF cards in a device which looked like a dog comb, I probably would have bought that too.

[Alex Raskin]

LOL on the dog comb :)))

Adaptive vs FS1: seriously, even the cheapest HDD with 5400rpm will let you record FS1.

If you can't, most likely you have a processor/memory/FSB bottleneck, and not the speed of the hard drive used...

Uncompressed: I toyed with it years ago, and can honestly say it won't make much difference vs CFHD FilmScan1 (called Quality 3 in SiliconDVR v1.x) on anything, including green screen.

Now. What's up with all that sheepish stuff. Go get'em, tiger!! :)

[Bob Hart]

"Sheepish stuff." - I guess it is safe to admit that I was so cheap that I tried to live with Premiere Pro 1/Cineform on a 1.6Ghz Pentium for as long as I could. It probably was not meant to work that way but it did - albeit slowly.

[Peter Moretti]

Bob,

A 1.6 Pentium and an SI2K? Talk about a five dollar saddle on a thoroughbred, LOL!! Godbless!