4:4:4 10bit single CMOS HD project - Page 77 at DVinfo.net

Go Back   DV Info Net > Special Interest Areas > Alternative Imaging Methods

Alternative Imaging Methods
DV Info Net is the birthplace of all 35mm adapters.


Closed Thread
 
Thread Tools Search this Thread
Old July 27th, 2004, 07:01 PM   #1141
Trustee
 
Join Date: Jan 2003
Location: Wilmington NC
Posts: 1,414
steve please provide a smear test if you can

take the camera and shoot a light that is taking about 5x5 pixels of less of the screen and see if you get dark streaks from it with the 3300

I am fooling with a footage clip on the machine in Combustion now..I will try and send a WMV via email if you want it...

Ok...I think I am starting to understand the smear thing...I have footage that is 16bit tiff files in Combustion..everything looks good..when I BOOST the gamma in the SHADOWS the "smear" comes out..if I just boost the MIDS and HIGHS the smear never shows...so how hard would you guys think you need to push the darks for this camera in a Cine type shoot for a film? also if you DON"T have a HOTSPOT in the frame and you push the darks hard they are fine....

things are looking better from my POV now....maybe I can work with this after all....

The new lens is a HUGE improvement over the cheap CCTV lenses I had...new one is a $350 8-51mm C-mount zoom

guys I need some FTP space if you want to see some clips/video.... I can't send files via email, they will not fit..anyone have FTP??
Obin Olson is offline  
Old July 27th, 2004, 08:32 PM   #1142
Trustee
 
Join Date: Mar 2003
Location: Virginia Beach, VA
Posts: 1,095
Quote:
Ok...I think I am starting to understand the smear thing...I have footage that is 16bit tiff files in Combustion..everything looks good..when I BOOST the gamma in the SHADOWS the "smear" comes out..if I just boost the MIDS and HIGHS the smear never shows...so how hard would you guys think you need to push the darks for this camera in a Cine type shoot for a film? also if you DON"T have a HOTSPOT in the frame and you push the darks hard they are fine....
The whole point is to push the shadows. If you're not pushing the shadows (of course there's a point to where you can push), then you're missing a couple bits in the low end-in other words you taking your 10-bit image and making it 8 or even 6-bits, cause those darks a hiding a huge amount of bit depth. You're looking at a linear image. If you check back a couple pages ago to where I placed some linear images in my post as samples, linear images are very dark, and you have to raise those darks to get the proper image. You have to apply an overall gamma of around 1.7-2.2. If the darks from that gamma gain go nuts, and you have to crush them, then you're loosing a lot of dynamic range. I've worked with a lot of linear images, and they should be clean when you do the gamma correction to match them to the gamma of the monitor/display device. There could be some non-linearity in the bottom, and I'm not sure how that skews the results or limits the dynamic range. Maybe if Les Dit could check out some of the image, he could find out what the true dynamic range of the image is.
Jason Rodriguez is offline  
Old July 27th, 2004, 08:53 PM   #1143
Trustee
 
Join Date: Jan 2003
Location: Wilmington NC
Posts: 1,414
ok 1.7-2.0 gamma is ok for the darks in what I shot today

someone needs to allow this message board atleast a way to upload stills for viewing on the boards!
Obin Olson is offline  
Old July 27th, 2004, 08:55 PM   #1144
Trustee
 
Join Date: Mar 2003
Location: Virginia Beach, VA
Posts: 1,095
Oh, Okay,

Then that's good.

BTW, I have ftp space (not much, but enough for stills).

Email me at jrod@mindspring.com and I'll post it.
Jason Rodriguez is offline  
Old July 27th, 2004, 08:58 PM   #1145
Major Player
 
Join Date: May 2004
Location: Knoxville, TN (USA)
Posts: 358
Quote:
Obin Olson wrote:
someone needs to allow this message board atleast a way to upload stills for viewing on the boards!
You can upload images to the wiki, but they are currently limited to 1 MB. This is probably way too small -- tomorrow I'll try to remember how to change the setting.
Rob Scott is offline  
Old July 27th, 2004, 09:00 PM   #1146
Trustee
 
Join Date: Jan 2003
Location: Wilmington NC
Posts: 1,414
Ok Jason..when I push the gamma in the DARKS at about 3.8 it looks really bad

shadows are ok at 1.6 gamma. No higher then that...what do you think?

I guess having the option to do anything with gamma is great when you compare this with videotape stuff...
Obin Olson is offline  
Old July 27th, 2004, 09:06 PM   #1147
Major Player
 
Join Date: Mar 2004
Location: chicago
Posts: 434
@Rob: 1 MB. This is probably way too small

Not necessarily, depending on the purpose of the upload -- 720p frames only take up about 800k with JPEG at 100% quality

- ben
Ben Syverson is offline  
Old July 27th, 2004, 09:09 PM   #1148
Regular Crew
 
Join Date: Sep 2002
Location: Loveland, CO
Posts: 101
FTP Space -- Have a little to share...

Quote:
Originally posted by Obin Olson : guys I need some FTP space if you want to see some clips/video.... I can't send files via email, they will not fit..anyone have FTP??
Hi Obin,

I can give a little FTP space and bandwidth, send me email and I give you a login and password.

marjamar@speedwing.net
__________________
Rodger Marjama
www.speedwing.net
Rodger Marjama is offline  
Old July 27th, 2004, 09:26 PM   #1149
Trustee
 
Join Date: Mar 2003
Location: Virginia Beach, VA
Posts: 1,095
Okay, here's Obin's pic:

http://home.mindspring.com/~jrod/gamma_DARKS_3.8.jpg

BTW Obin, at 10bits, and a gamma of 3.8, there is no way you're going to make those blacks look good.

In Combustion you should go to the "Master" setting (not shadows, mids, highs), and then apply a gamma of 1.7.

Actually even better, you should go to the LUT in the footage tab (under output), and then give that a gamma of 1.7 so that there's no "filters" being applied. That's the nice thing about Combustion, you can apply LUT's to images, something that AE doesn't let you do. Just watch out, because the default LUT clips the shadows and highlights, you don't want that, so stretch the curve over to the end of the highlights and shadows. But try the LUT feature. And again, you need an overall gamma of 1.7, not separate gammas for each of the different sections of the image, because those gammas are ON TOP of the gamma of the master. So you're applying a gamma of 3.8 to the base gamma of 1, not applying an overall 1.7 which would look much different.
Jason Rodriguez is offline  
Old July 27th, 2004, 09:28 PM   #1150
Trustee
 
Join Date: Jan 2003
Location: Wilmington NC
Posts: 1,414
ohhhh....hmm I did not know that...

cool I will dink around with the LUT...


thanks..good stuff!
Obin Olson is offline  
Old July 27th, 2004, 09:30 PM   #1151
Inner Circle
 
Join Date: May 2003
Location: Australia
Posts: 2,761
<<<-- Originally posted by Ben Syverson :

@Wayne: How fast can you run the shutter and not drop below 24FPS in 8 bit and in 10 bit modes, and can the software be setup to force a set synced frame rate (24fps)?

You're clearly not reading the posts -- if you catch up on the discussion, you'll see where we're at.

@Wayne: What is the perforamnce difference when running global shutter to compared to rolling shutter.

Again, we've been over this, for now it's rolling shutter only.
- ben -->>>

Sorry, I did but I think I mean a few more advanced things then were covered.

I know you have talked about it not doing 24fps exactly, but I'm curiiouse if the config and options have a more advanced realtime mode that forces the sytem to let it sync to an exact FPS. I don't remember you mentioning how fast the shutter could run. In Obin's camera faster shutter means more bandwith (which maxes out), but if yours had a frame buffer you should be able to do much faster shutters.

When I said performance difference between Global and rolling, I was meaning in terms of any effects on picture quality and max shutter speed (global leaks a bit, and who knows what else).

Thanks

Wayne.
Wayne Morellini is offline  
Old July 27th, 2004, 09:33 PM   #1152
Trustee
 
Join Date: Jan 2003
Location: Wilmington NC
Posts: 1,414
So jason you don't think that smearing is all that bad ?

I will send you a raw tiff file of that 3.8 DRAKS gamma pic for you to take a look at
Obin Olson is offline  
Old July 27th, 2004, 09:40 PM   #1153
Major Player
 
Join Date: Mar 2004
Location: chicago
Posts: 434
Wayne, like I mentioned before, currently there is no way to "lock" the frame rate, but as I mentioned, Sumix is currently planning on incorporating such a feature. If you want to run at 24fps exactly, you'll have to run the camera at 40mhz, and take only 24 of the 40 or so frames per second. At 24mhz, you're always going to be brushing up against 24fps. Personally, I'd rather run at 24mhz/23.5fps and take my increased exposure even if it means a few more editing headaches. But folks who want absolute sound sync on 50 seconds of footage :) can set that up at 40mhz.

I haven't tested global vs rolling because currently the firmware/software is rolling-only for motion. Global would clearly be preferable, and I've brought that up with Sumix, but until that's a possibility, I won't waste time testing it.

- ben
Ben Syverson is offline  
Old July 27th, 2004, 10:07 PM   #1154
Trustee
 
Join Date: Jan 2003
Location: Wilmington NC
Posts: 1,414
clip that has been CC and gamma set at 1.7

http://obin.weet.us/cc-1.wmv
http://obin.weet.us/raw image.tiff
http://home.mindspring.com/~jrod/gamma_DARKS_3.8.jpg

2 above are the same shots..if you can open the raw black and white take a look at that...the dark is the one I pushed the crap out of the dark GAMMA
Obin Olson is offline  
Old July 27th, 2004, 10:13 PM   #1155
Trustee
 
Join Date: Mar 2003
Location: Virginia Beach, VA
Posts: 1,095
Obin,

I think you need to shoot an 18% grey card.

Because right now we have NO idea how much dynamic range we're getting out of this camera.

Your images look good (sans the bad bayer demosaicer), but they might be too bright, you might be clipping too much of the shadow dynamic range.

Get a light meter, and shoot a grey card. I'm not sure what the ISO of these cameras is, you might be able to find that out from Steve. But once you find that out, go shoot a grey card, and see where that shows up in your file. Then you can see how much gamma correction it takes to make that 18% grey 50% grey inside Combustion. A white card is 2 and 2/3 stops over 18% grey. So then you can see how many stops over white that you're getting before it clips.

Without these tests, and no pun intended, we're shooting in the dark :-)

But your images do look good :-)
Jason Rodriguez is offline  
Closed Thread

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > Special Interest Areas > Alternative Imaging Methods

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 11:33 AM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network