XDCAM and low light

Craig Seeman · October 9th, 2007, 02:47 PM

Thanks for posting that Steven.

Two things jump out at me. Memory cache recording not available for this model. I have heard elsewhere that although not available at initial release it will be a firmware upgrade. I'm going to double check that with Sony if I can.

The second is the claim that it takes 3 minutes to download 1 hour of "footage" from the SxS card. At 3x speed it would be 20 minutes to download 1 hour of video (recorded at 35mbps). I can't help someone got confused between 3x and 3 minutes.

Serena Steuart · October 9th, 2007, 05:28 PM

At -3dB gain the EX1 provides correct exposure rated at 800ASA. Shots of a model exposed at +/- 2 stops corrected well, without noise being visible in the 2 stops under material I saw projected (unfortunately using a data projector). 2 stops over and the high lights were burned, but the soft graduation looked natural. Don't know the gamma curve selected. Was impressed by images in a poorly lit auditorium (at -3dB) where the Z1 would have needed 18dB. This was a default gamma and looked even better when I dialed in black stretch. I didn't have time to try out other cinegamma curves.

David Koo · October 9th, 2007, 05:32 PM

I hope this low light comparison is accurate...

That would be simply awesome...

But, the surface area gained by going to 1/2 inch chips does not seem intuitively to explain these kind of impressive results...

To me, these results seem to defy physics...

Again I hope it's true, but I'm a little skeptical...

Steven Thomas · October 9th, 2007, 06:15 PM

Thanks Serena,
Wow... It looks like the EX will be a decent perfomer in low light. This is VERY good news! This makes me believe the sample images at the start of this thread are looking better and better....

Jiri Bakala · October 9th, 2007, 10:07 PM

Quote:

Originally Posted by Craig Seeman

The second is the claim that it takes 3 minutes to download 1 hour of "footage" from the SxS card. At 3x speed it would be 20 minutes to download 1 hour of video (recorded at 35mbps). I can't help someone got confused between 3x and 3 minutes.

Here is a quote from a published review (http://dvuser.co.uk/content.php?CID=171):

"I suspect Sony have left Proxy files from the EX1 for a number of reasons. First, to save space on the cards to allow for more recording time of luscious HD footage, and also, the actual import time for full HD files from the SxS cards can only be described as 'blisteringly fast'. It is getting close to 20x real time. 1-hour of full 1920x1080 HQ HD footage can be imported via the XDCAM EX transfer software in approximately 4 minutes flat! "

20x the transfer speed...? Whoa! That's amazing if true!

Alister Chapman · October 10th, 2007, 03:03 AM

3x Transfer speed is for XDCAM HD disk based systems. SxS is much much faster. Rough tests I did at IBC suggested transfer speeds of around 4 to 5 mins for an hours worth of HQ material.

Craig Seeman · October 10th, 2007, 03:18 AM

Sorry for misunderstanding the transfer rate.

!!!! I'm sold!!!!

The ability to offload and even verify the material will not be much longer than a quick coffee break during a shoot.

I can't help but think this camera is going to be a viable ENG camera as News moves into HiDef.

Alister, I assume you were offloading to a laptop with SxS port (MacBook or Vaio), no?

Quote:

Originally Posted by Alister Chapman

3x Transfer speed is for XDCAM HD disk based systems. SxS is much much faster. Rough tests I did at IBC suggested transfer speeds of around 4 to 5 mins for an hours worth of HQ material.

Brian Cassar · October 10th, 2007, 04:47 AM

Quote:

Originally Posted by Alister Chapman

3x Transfer speed is for XDCAM HD disk based systems. SxS is much much faster. Rough tests I did at IBC suggested transfer speeds of around 4 to 5 mins for an hours worth of HQ material.

Is this transfer speed referring to transfer of files

1) from the camera itself connectd directly to a pc, or
2) from an express port on a laptop, or
3) from the USB card reader connected to a pc?

Will the 3 different modes of transfer mentioned above have any effect on the transfer rate? I've noticed that the USB express card reader neds to be connected to a mains supply - rather strange since all current card readers draw the necessary power from the USB itself. It seems that there are some more electronics inside there doing soemthing. I wonder...

Alister Chapman · October 10th, 2007, 06:12 AM

The transfer from SXS is limited by by the speed of the computers hard drive! The speed is the same from the camera or USB reader and just a tiny bit faster if you have an express slot on the computer. As I said the main bottleneck is the the speed of the computers hard drive as the SxS card can stream at 800Mb/s.

Kevin Shaw · October 10th, 2007, 08:27 AM

Quote:

Originally Posted by Craig Seeman

The second is the claim that it takes 3 minutes to download 1 hour of "footage" from the SxS card. At 3x speed it would be 20 minutes to download 1 hour of video (recorded at 35mbps). I can't help someone got confused between 3x and 3 minutes.

As others have noted it apparently is quite fast, which makes sense given that the maximum stated transfer rate of 800 Mbps is more than 20 times the maximum recording bandwidth of 35 Mbps. So 3+ minutes to transfer 60 minutes of footage is plausible.

Craig Seeman · October 10th, 2007, 08:11 PM

And yet when I asked the Sony Rep at HD World in NYC today (they had 2 EX1 on hand) he said he had tested the previous day on a recent Sony Vaio and found the transfer speed to be about 3 times real time (although he seemed a bit unsure).

Quote:

Originally Posted by Kevin Shaw

As others have noted it apparently is quite fast, which makes sense given that the maximum stated transfer rate of 800 Mbps is more than 20 times the maximum recording bandwidth of 35 Mbps. So 3+ minutes to transfer 60 minutes of footage is plausible.

Brian Cassar · October 15th, 2007, 01:42 AM

Returning back to the original title of this thread, I've just noticed that B&H are stating that minimum illumination for the EX1 is 4 lux at f1.6 and 18dB!! From where did they get this figure? This is not what I call a low light capable camera at these figures! I've noticed also that they are stating that sensitivity is not quoted by manufacturer - in fact it was! I hope that it is a typo error... Even though the original official min illumination is stated as being 0.14 lx (typical) (1920 x 1080/59.94i mode, F1.9, +18 dB gain, with 64-frame accumulation), if one had to switch off the 64-frame accumulation and take in cosideration that it is a F1.9 lens, I do not think the min illumination will end up as 4 lux. .....I hope......

Serena Steuart · October 15th, 2007, 02:06 AM

The 0.14 lux is an imaginative statement and is of interest if filming comets (quite useful, actually). The other figure is f/10 on a white card (90% reflectance) at 2000 lux, presumably at -3dB gain, 1/60 second ; from which I calculate 8 lux at 18dB gain at f/2.0 at 1/60sec and about 4 lux at 1/33 sec. So it's possible. Going the other way: 64 x 0.14 = 8.96 lux. I think I've seen the 8 on a presentation table, so that might be right.

edit: when the EX is put in the "low light" category that is relative to other HD cameras, so if one has been shooting with a Z1 then 8 lux is good.

Brian Cassar · October 15th, 2007, 02:30 AM

Thanks Serena for the technical reply. The problem is that I'm presently used to filming at very low light situations with an SD Sony camcorder (DSR-300) rated at F11 at 2000lux - and it does wonders. I know that SD and HD sensors differ but I'm just curious to know how much will I loose with a F10 at 2000 lux sensitivity? Will it be just one stop or could it be more?

Martin Mayer · October 15th, 2007, 04:43 AM

Quote:

Originally Posted by Serena Steuart

edit: when the EX is put in the "low light" category that is relative to other HD cameras, so if one has been shooting with a Z1 then 8 lux is good.

Confused: is that "8 lux is good" statement supposed to be compared with the quoted "4 lux" rating given in the Z1 spec?

October 10th, 2007, 03:03 AM	#21
Alister Chapman Inner Circle Join Date: Dec 2005 Location: Bracknell, Berkshire, UK Posts: 4,957	3x Transfer speed is for XDCAM HD disk based systems. SxS is much much faster. Rough tests I did at IBC suggested transfer speeds of around 4 to 5 mins for an hours worth of HQ material. __________________ Alister Chapman, Film-Maker/Stormchaser http://www.xdcam-user.com/alisters-blog/ My XDCAM site and blog. http://www.hurricane-rig.com

October 10th, 2007, 06:12 AM	#24
Alister Chapman Inner Circle Join Date: Dec 2005 Location: Bracknell, Berkshire, UK Posts: 4,957	The transfer from SXS is limited by by the speed of the computers hard drive! The speed is the same from the camera or USB reader and just a tiny bit faster if you have an express slot on the computer. As I said the main bottleneck is the the speed of the computers hard drive as the SxS card can stream at 800Mb/s. __________________ Alister Chapman, Film-Maker/Stormchaser http://www.xdcam-user.com/alisters-blog/ My XDCAM site and blog. http://www.hurricane-rig.com

October 15th, 2007, 02:06 AM	#28
Serena Steuart Major Player Join Date: Jun 2006 Location: Studio Alnitak, Melbourne, Victoria, Australia Posts: 640 Images: 3	The 0.14 lux is an imaginative statement and is of interest if filming comets (quite useful, actually). The other figure is f/10 on a white card (90% reflectance) at 2000 lux, presumably at -3dB gain, 1/60 second ; from which I calculate 8 lux at 18dB gain at f/2.0 at 1/60sec and about 4 lux at 1/33 sec. So it's possible. Going the other way: 64 x 0.14 = 8.96 lux. I think I've seen the 8 on a presentation table, so that might be right. edit: when the EX is put in the "low light" category that is relative to other HD cameras, so if one has been shooting with a Z1 then 8 lux is good. Last edited by Serena Steuart; October 15th, 2007 at 02:11 AM. Reason: additional comment

October 9th, 2007, 02:47 PM	#16
Craig Seeman Inner Circle Join Date: Feb 2004 Location: Brooklyn, NY, USA Posts: 3,841	Thanks for posting that Steven. Two things jump out at me. Memory cache recording not available for this model. I have heard elsewhere that although not available at initial release it will be a firmware upgrade. I'm going to double check that with Sony if I can. The second is the claim that it takes 3 minutes to download 1 hour of "footage" from the SxS card. At 3x speed it would be 20 minutes to download 1 hour of video (recorded at 35mbps). I can't help someone got confused between 3x and 3 minutes.

October 9th, 2007, 05:28 PM	#17
Serena Steuart Major Player Join Date: Jun 2006 Location: Studio Alnitak, Melbourne, Victoria, Australia Posts: 640 Images: 3	At -3dB gain the EX1 provides correct exposure rated at 800ASA. Shots of a model exposed at +/- 2 stops corrected well, without noise being visible in the 2 stops under material I saw projected (unfortunately using a data projector). 2 stops over and the high lights were burned, but the soft graduation looked natural. Don't know the gamma curve selected. Was impressed by images in a poorly lit auditorium (at -3dB) where the Z1 would have needed 18dB. This was a default gamma and looked even better when I dialed in black stretch. I didn't have time to try out other cinegamma curves.

October 9th, 2007, 05:32 PM	#18
David Koo Regular Crew Join Date: Oct 2006 Location: Cincinnati, OH Posts: 51	I hope this low light comparison is accurate... That would be simply awesome... But, the surface area gained by going to 1/2 inch chips does not seem intuitively to explain these kind of impressive results... To me, these results seem to defy physics... Again I hope it's true, but I'm a little skeptical...

October 9th, 2007, 06:15 PM	#19
Steven Thomas Trustee Join Date: Sep 2005 Location: Gilbert, AZ Posts: 1,896	Thanks Serena, Wow... It looks like the EX will be a decent perfomer in low light. This is VERY good news! This makes me believe the sample images at the start of this thread are looking better and better....

October 15th, 2007, 01:42 AM	#27
Brian Cassar Major Player Join Date: Jan 2007 Location: Malta Posts: 306	Returning back to the original title of this thread, I've just noticed that B&H are stating that minimum illumination for the EX1 is 4 lux at f1.6 and 18dB!! From where did they get this figure? This is not what I call a low light capable camera at these figures! I've noticed also that they are stating that sensitivity is not quoted by manufacturer - in fact it was! I hope that it is a typo error... Even though the original official min illumination is stated as being 0.14 lx (typical) (1920 x 1080/59.94i mode, F1.9, +18 dB gain, with 64-frame accumulation), if one had to switch off the 64-frame accumulation and take in cosideration that it is a F1.9 lens, I do not think the min illumination will end up as 4 lux. .....I hope......

October 15th, 2007, 02:30 AM	#29
Brian Cassar Major Player Join Date: Jan 2007 Location: Malta Posts: 306	Thanks Serena for the technical reply. The problem is that I'm presently used to filming at very low light situations with an SD Sony camcorder (DSR-300) rated at F11 at 2000lux - and it does wonders. I know that SD and HD sensors differ but I'm just curious to know how much will I loose with a F10 at 2000 lux sensitivity? Will it be just one stop or could it be more?