Visible grain with the FX1

David Delaney · July 23rd, 2006, 03:17 PM

I am wondering about something. I have a scene that I am just testing. With Zebra stripes on, most of it is blown out - so I know there is more than enough light, but there seems to be alot of grain. Not sure why or if I am doing something wrong. It is almost like I have a DOF adapter on it...any ideas? My iris is open all the way, but the gain is on 9db (also, is there a way to change the gain in small increments?)

Ben Winter · July 23rd, 2006, 03:29 PM

If gain is on, it'll give you grain. That's what gain does, gives you brightness at the expense of video noise (grain). If you don't want grain, take off the gain--especially if things are blown out, you obviously don't need it.

My rule of thumb is use gain as a last resort for low-light situations. The image quality goes downhill as you increase gain.

In the settings menu you can change what H M L settings are for gain in smaller increments, so you could change medium gain to +7dB instead of +9.

Ideally you shouldn't be using gain at all. If you do, don't go above 3db.

Ron Evans · July 23rd, 2006, 04:13 PM

I regularly use 12db of gain with aperture at f4 on my FX1 in theatre environment with no noticable grain. There must be something else wrong at 9db, I never use iris wide open so that may have an effect. Gain is defined by the engineers. O on one camera is very different than 0 on another camera even using the same CCD's. The FX1 is much better in this regard compared to the DVX100 which becomes unusable above 6db of gain.

Ron Evans

Chris Barcellos · July 23rd, 2006, 04:21 PM

In viewing my HDV stuff on my Dell monitor LCD flat panel monitor, I notice a lot of grain too, but I think that has to do with the monitor, and perhaps the rescaling process to show it on the monitor. Any one notice that with their LCD monitors ?

David Delaney · July 23rd, 2006, 05:30 PM

I am viewing the grain right on the flip out screen.

Chris Barcellos · July 23rd, 2006, 06:29 PM

Quote:

Originally Posted by David Delaney

I am viewing the grain right on the flip out screen.

You should not judge the grain by the LCD. How does the product look on screen, or in edit ?

David Delaney · July 23rd, 2006, 06:43 PM

Haven't gotten that far yet. I only have VV5, so I don't know if it will handle HD at this point...I will probably have to upgrade to see the results on screen.

Ron Evans · July 23rd, 2006, 08:18 PM

What does the picture look like played back from the camera to a TV through the component outputs? Neither the camera LCD or a LCD PC monitor will give a good indication of picture quality. You need to feed the output to a true HD monitor. I also have the Dell 24" monitor and it is nowhere near as good as the Sony HiScan. The scaler in the Dell causes problems in playback even at the 1:1 pixel setting turning the picture into a poor cable image with motion lag etc.

Ron Evans

Carlos E. Martinez · July 24th, 2006, 05:40 AM

Apparently you need something like this to view HD in an SD monitor:

http://www.blackmagic-design.com/products/hdlink/

Seems to have sold thousands around the world.

Ron Evans · July 24th, 2006, 06:58 AM

Carlos that is a SDI converter to DVi or HDMI. The HD output directly from the FX1 is component or iLink and will be interlaced 1080i. So any screen will need to be either native interlace ( HD CRT ) or in the case of LCD or Plasma have to use a scaler to at the very least convert to progressive. The Dell 24" PC monitor LCD has ample resolution and all the connectors needed for the FX1 directly but is progressive and I think it is this converter in the Dell that degrades the picture from the FX1. Software conversion in NLE's produces a better picture on the Dell but still inferior to the Sony HiScan CRT. I think there are two very important parameters for displaying HD, the scaler that is being used and the speed of the display ( a real problem for low cost LCD's). IF you don't have a HD CRT or high quality progressive display then you will not see the true output from the FX1.

Ron Evans

Richard Iredale · July 24th, 2006, 10:52 PM

The FX1/Z1 are well-known for their LACK of video noise when compared to other HDV cameras. On some informal tests I ran with the FX1 against the VX2000 last spring, I noticed that the VX2000 was about two stops more light-sensitive. Then I noticed that there was a lot less video noise in the FX1 image (this was with the lens wide-open and +18db of gain). I imported the FX1 footage into Vegas and boosted it further by one stop. Even then the video noise was not as bad as on the VX2000 image. So I would have to conclude that the FX1 can easily be boosted by 18db with only a modest hit in noise.

July 23rd, 2006, 03:17 PM	#1
David Delaney Trustee Join Date: Feb 2006 Location: Niagara Ontario Canada Posts: 1,121	Visible grain with the FX1 - even when it is bright? I am wondering about something. I have a scene that I am just testing. With Zebra stripes on, most of it is blown out - so I know there is more than enough light, but there seems to be alot of grain. Not sure why or if I am doing something wrong. It is almost like I have a DOF adapter on it...any ideas? My iris is open all the way, but the gain is on 9db (also, is there a way to change the gain in small increments?)

July 23rd, 2006, 04:21 PM	#4
Chris Barcellos Inner Circle Join Date: Nov 2005 Location: Elk Grove CA Posts: 6,838	In viewing my HDV stuff on my Dell monitor LCD flat panel monitor, I notice a lot of grain too, but I think that has to do with the monitor, and perhaps the rescaling process to show it on the monitor. Any one notice that with their LCD monitors ? __________________ Chris J. Barcellos

July 23rd, 2006, 03:29 PM	#2
Ben Winter Trustee Join Date: Jun 2005 Location: Hollywood, CA Posts: 1,675 Images: 1	If gain is on, it'll give you grain. That's what gain does, gives you brightness at the expense of video noise (grain). If you don't want grain, take off the gain--especially if things are blown out, you obviously don't need it. My rule of thumb is use gain as a last resort for low-light situations. The image quality goes downhill as you increase gain. In the settings menu you can change what H M L settings are for gain in smaller increments, so you could change medium gain to +7dB instead of +9. Ideally you shouldn't be using gain at all. If you do, don't go above 3db.

July 23rd, 2006, 04:13 PM	#3
Ron Evans Inner Circle Join Date: Mar 2003 Location: Ottawa, Ontario, Canada Posts: 4,220	I regularly use 12db of gain with aperture at f4 on my FX1 in theatre environment with no noticable grain. There must be something else wrong at 9db, I never use iris wide open so that may have an effect. Gain is defined by the engineers. O on one camera is very different than 0 on another camera even using the same CCD's. The FX1 is much better in this regard compared to the DVX100 which becomes unusable above 6db of gain. Ron Evans

July 23rd, 2006, 05:30 PM	#5
David Delaney Trustee Join Date: Feb 2006 Location: Niagara Ontario Canada Posts: 1,121	I am viewing the grain right on the flip out screen.

July 23rd, 2006, 06:43 PM	#7
David Delaney Trustee Join Date: Feb 2006 Location: Niagara Ontario Canada Posts: 1,121	Haven't gotten that far yet. I only have VV5, so I don't know if it will handle HD at this point...I will probably have to upgrade to see the results on screen.

July 23rd, 2006, 08:18 PM	#8
Ron Evans Inner Circle Join Date: Mar 2003 Location: Ottawa, Ontario, Canada Posts: 4,220	What does the picture look like played back from the camera to a TV through the component outputs? Neither the camera LCD or a LCD PC monitor will give a good indication of picture quality. You need to feed the output to a true HD monitor. I also have the Dell 24" monitor and it is nowhere near as good as the Sony HiScan. The scaler in the Dell causes problems in playback even at the 1:1 pixel setting turning the picture into a poor cable image with motion lag etc. Ron Evans

July 24th, 2006, 05:40 AM	#9
Carlos E. Martinez Trustee Join Date: Oct 2003 Location: Rio de Janeiro, Brasil Posts: 1,138	Apparently you need something like this to view HD in an SD monitor: http://www.blackmagic-design.com/products/hdlink/ Seems to have sold thousands around the world.

July 24th, 2006, 06:58 AM	#10
Ron Evans Inner Circle Join Date: Mar 2003 Location: Ottawa, Ontario, Canada Posts: 4,220	Carlos that is a SDI converter to DVi or HDMI. The HD output directly from the FX1 is component or iLink and will be interlaced 1080i. So any screen will need to be either native interlace ( HD CRT ) or in the case of LCD or Plasma have to use a scaler to at the very least convert to progressive. The Dell 24" PC monitor LCD has ample resolution and all the connectors needed for the FX1 directly but is progressive and I think it is this converter in the Dell that degrades the picture from the FX1. Software conversion in NLE's produces a better picture on the Dell but still inferior to the Sony HiScan CRT. I think there are two very important parameters for displaying HD, the scaler that is being used and the speed of the display ( a real problem for low cost LCD's). IF you don't have a HD CRT or high quality progressive display then you will not see the true output from the FX1. Ron Evans

July 24th, 2006, 10:52 PM	#11
Richard Iredale Regular Crew Join Date: Dec 2003 Location: Portland, OR Posts: 67	The FX1/Z1 are well-known for their LACK of video noise when compared to other HDV cameras. On some informal tests I ran with the FX1 against the VX2000 last spring, I noticed that the VX2000 was about two stops more light-sensitive. Then I noticed that there was a lot less video noise in the FX1 image (this was with the lens wide-open and +18db of gain). I imported the FX1 footage into Vegas and boosted it further by one stop. Even then the video noise was not as bad as on the VX2000 image. So I would have to conclude that the FX1 can easily be boosted by 18db with only a modest hit in noise.