using a pd150 for D/A conversions- please help with techie question at DVinfo.net

Ashley Cooper · May 17th, 2004, 01:00 PM

To date I've been using my firewire out to my pd150 and then the rca or s-video out from the camera to the external monitor for previews. As I understand it, there needs to be a 7.5 IRE pedistal added when going from digital to analog and prosumer cameras often add around 2-5 IRE just so things don't look horribly wrong. Still, this would not really add accurate results.
Can anyone tell me how much, if any, IRE the pd150 adds?
Also, if I am wrong about anything I've stated above I would really appreciate a correction (and yes I have read Adam Wilt's article and seen the jvc commercial several times).
Thanks for any help!

Greg J. Winter · May 17th, 2004, 08:45 PM

I have measured my set-up with lens cap on as 3.7 IRE.

Greg J. Winter
www.gregjwinter.com

Ashley Cooper · May 18th, 2004, 01:03 AM

Okay, now I'm really confused. If that is what you got with the cap on then you're saying the pd150 adds 3.7 IRE when it records, right? Correct me if I'm wrong, but shouldn't it be at 0 IRE?
Doesn't this ROYALLY mess things up? Unless you're saying that the camera adds 3.7 IRE to the video outputs (for viewing on an external monitor, etc) but records at 0 IRE on the tape then we're always going to get inaccuracte material, right.
3.7 IRE is a very suspicious number at halfway to the 7.5 pedistal. I really hope Sony isn't doing one of their halfway measures of dealing with real problems again.
Sorry for my confusion, but could you tell me how you deal with the 7.5 IRE pedisal issue in NTSC land?
Thanks ahead of time for any help!

Greg J. Winter · May 18th, 2004, 06:53 AM

Unfortunately that is what we have to deal with here.... it's one of the issues we have to deal with using a PD150 or VX2K (both use the same logic board & video chips. At least there is some setup! :-)

So I am saying that I measured this on the video output (that you would use for viewing on monitor). You can use your NLE to change the levels to fit your needs.... I would not a proc amp between the camera and monitor. Adjust the material that you have in the NLE. For most of what I work with a setup of 3.7 is fine for me.... it was the sound the camera's record was what I had the biggest problem with.

Mike Rehmus · May 18th, 2004, 09:02 AM

<<<-- Originally posted by Ashley Cooper : Okay, now I'm really confused. If that is what you got with the cap on then you're saying the pd150 adds 3.7 IRE when it records, right? Correct me if I'm wrong, but shouldn't it be at 0 IRE?
Doesn't this ROYALLY mess things up? Unless you're saying that the camera adds 3.7 IRE to the video outputs (for viewing on an external monitor, etc) but records at 0 IRE on the tape then we're always going to get inaccuracte material, right.
3.7 IRE is a very suspicious number at halfway to the 7.5 pedistal. I really hope Sony isn't doing one of their halfway measures of dealing with real problems again.
Sorry for my confusion, but could you tell me how you deal with the 7.5 IRE pedisal issue in NTSC land?
Thanks ahead of time for any help! -->>>

The camera always adds setup to the analog outputs, regardless of the source. The setup level recorded to tape and output via the iLink port is at 0 as it should be.

The 3.7 IRE setup may or may not be deliberate although I cannot see why Sony would not be controlling this. I'd guess it is a compromise since, although Sony normally handles this issue correctly, the rest of the world may not.

I always have a proc amp and a waveform monitor in series with the analog signal out of my NLE. That way I can set the signal correctly before I send it to VHS/S-VHS tape. The NLE is controllable for the amount of setup and does properly deliver 7.5 units when requested.

Alternatively, my DSR-20 does add the proper (7.5) IRE units of setup on its analog outputs as does my DSR-300.

Ashley Cooper · May 19th, 2004, 01:46 AM

Frankly, that really upsets me and is why I'm hesitant to buy Sony stuff. They do the same thing with their video projectors I believe. Instead of seperate settings for 60hz for NTSC and 50hz for Pal, they make a constant 55hz.
People can slam me for this if they want, but it's this kind of thing that erodes customer confidence and makes it seem like their out to nickle and dime you to death.
Oh well, Panasonic may not be much better.

May 17th, 2004, 01:00 PM	#1
Ashley Cooper Regular Crew Join Date: Feb 2004 Location: Birmingham, AL Posts: 85	using a pd150 for D/A conversions- please help with techie question To date I've been using my firewire out to my pd150 and then the rca or s-video out from the camera to the external monitor for previews. As I understand it, there needs to be a 7.5 IRE pedistal added when going from digital to analog and prosumer cameras often add around 2-5 IRE just so things don't look horribly wrong. Still, this would not really add accurate results. Can anyone tell me how much, if any, IRE the pd150 adds? Also, if I am wrong about anything I've stated above I would really appreciate a correction (and yes I have read Adam Wilt's article and seen the jvc commercial several times). Thanks for any help!

May 17th, 2004, 08:45 PM	#2
Greg J. Winter New Boot Join Date: Jan 2004 Location: Rochester, NY Posts: 21	Set-up on my camera I have measured my set-up with lens cap on as 3.7 IRE. Greg J. Winter www.gregjwinter.com __________________ Greg J. Winter Electronics Engineer www.gregjwinter.com

May 18th, 2004, 01:03 AM	#3
Ashley Cooper Regular Crew Join Date: Feb 2004 Location: Birmingham, AL Posts: 85	Totally confused now- please help! Okay, now I'm really confused. If that is what you got with the cap on then you're saying the pd150 adds 3.7 IRE when it records, right? Correct me if I'm wrong, but shouldn't it be at 0 IRE? Doesn't this ROYALLY mess things up? Unless you're saying that the camera adds 3.7 IRE to the video outputs (for viewing on an external monitor, etc) but records at 0 IRE on the tape then we're always going to get inaccuracte material, right. 3.7 IRE is a very suspicious number at halfway to the 7.5 pedistal. I really hope Sony isn't doing one of their halfway measures of dealing with real problems again. Sorry for my confusion, but could you tell me how you deal with the 7.5 IRE pedisal issue in NTSC land? Thanks ahead of time for any help!

May 18th, 2004, 06:53 AM	#4
Greg J. Winter New Boot Join Date: Jan 2004 Location: Rochester, NY Posts: 21	Unfortunately that is what we have to deal with here.... it's one of the issues we have to deal with using a PD150 or VX2K (both use the same logic board & video chips. At least there is some setup! :-) So I am saying that I measured this on the video output (that you would use for viewing on monitor). You can use your NLE to change the levels to fit your needs.... I would not a proc amp between the camera and monitor. Adjust the material that you have in the NLE. For most of what I work with a setup of 3.7 is fine for me.... it was the sound the camera's record was what I had the biggest problem with. __________________ Greg J. Winter Electronics Engineer www.gregjwinter.com

May 18th, 2004, 09:02 AM	#5
Mike Rehmus Wrangler Join Date: May 2002 Location: Vallejo, California Posts: 4,049	Re: Totally confused now- please help! <<<-- Originally posted by Ashley Cooper : Okay, now I'm really confused. If that is what you got with the cap on then you're saying the pd150 adds 3.7 IRE when it records, right? Correct me if I'm wrong, but shouldn't it be at 0 IRE? Doesn't this ROYALLY mess things up? Unless you're saying that the camera adds 3.7 IRE to the video outputs (for viewing on an external monitor, etc) but records at 0 IRE on the tape then we're always going to get inaccuracte material, right. 3.7 IRE is a very suspicious number at halfway to the 7.5 pedistal. I really hope Sony isn't doing one of their halfway measures of dealing with real problems again. Sorry for my confusion, but could you tell me how you deal with the 7.5 IRE pedisal issue in NTSC land? Thanks ahead of time for any help! -->>> The camera always adds setup to the analog outputs, regardless of the source. The setup level recorded to tape and output via the iLink port is at 0 as it should be. The 3.7 IRE setup may or may not be deliberate although I cannot see why Sony would not be controlling this. I'd guess it is a compromise since, although Sony normally handles this issue correctly, the rest of the world may not. I always have a proc amp and a waveform monitor in series with the analog signal out of my NLE. That way I can set the signal correctly before I send it to VHS/S-VHS tape. The NLE is controllable for the amount of setup and does properly deliver 7.5 units when requested. Alternatively, my DSR-20 does add the proper (7.5) IRE units of setup on its analog outputs as does my DSR-300. __________________ Mike Rehmus Hey, I can see the carrot at the end of the tunnel!

May 19th, 2004, 01:46 AM	#6
Ashley Cooper Regular Crew Join Date: Feb 2004 Location: Birmingham, AL Posts: 85	Wow, that's really not good Frankly, that really upsets me and is why I'm hesitant to buy Sony stuff. They do the same thing with their video projectors I believe. Instead of seperate settings for 60hz for NTSC and 50hz for Pal, they make a constant 55hz. People can slam me for this if they want, but it's this kind of thing that erodes customer confidence and makes it seem like their out to nickle and dime you to death. Oh well, Panasonic may not be much better.