Resolution loss and low light response at 1/30 or 1/25?

Anhar Miah · December 16th, 2004, 05:43 PM

component hey?

could it be that it is uncompressed signal i.e before the mpeg2 hit thus your seeing no res loss?

I know this whole issuse was raised before about compressed not compressed component output, please lets not start that again..

John Jay · December 16th, 2004, 08:33 PM

<<<-- Originally posted by Toke Lahti : <<<-- Originally posted by John Jay : its more an interlacing thing, than format. If the speed drops below the field rate than it delivers the dominant field. -->>>

But is it like this with fx1?
I got a quick chance to test a little a bit of my fellow workers fx1 and I also noticed that it's resolution didn't lower to half with slower shutter.

I didn't have resolution charts with me or anything but we shot high resolution poster with fine print in it and monitored it with hp's L2335 monitor (with component hd connection).

I didn't see any diffrence in resolution.
How is this possible?
Are the ccd's after all progressive?

Eg. if shutter speed is 1/12 s, exposure & readout time for one field is 1/24 s, so camera has to record that one field to both fields of one frame on tape. For PAL tape mechanism has to write one field for every 1/50 s, so info from another field does not get soon enough. Recording two even fields and then two odd field would lead to 25 Hz flicker problems.
So slow shutter with interlaced ccd's means always that you can use only one field. Right? -->>>

If you grab a still from footage shot below 1/50 and examine it in say Photoshop with a shot at 1/50 you will see a difference...

Toke Lahti · December 17th, 2004, 06:31 AM

<<<-- Originally posted by John Jay : If you grab a still from footage shot below 1/50 and examine it in say Photoshop with a shot at 1/50 you will see a difference... -->>>

Why I didn't see the diffrence with the monitor?
It has a resolution of 1920x1200, so if the resolution drops to half, it should be _very_ noticable.
If the resolution does not drop to half, does the camera then have progressive ccd's?
Then Reel-stream mod would become very interesting...

John Jay · December 17th, 2004, 04:04 PM

<<<-- Originally posted by Toke Lahti :

Why I didn't see the diffrence with the monitor?
It has a resolution of 1920x1200, so if the resolution drops to half, it should be _very_ noticable.
If the resolution does not drop to half, does the camera then have progressive ccd's?
Then Reel-stream mod would become very interesting... -->>>

I dont know, but if you post some grabs I will attempt to answer your Q

Also if it was progressive at slower shutter speed it would look like you boosted gain by 6db - did you see extra noise?

Ignacio Rodriguez · December 20th, 2004, 02:14 PM

Barry Green has demonstrated that there is resolution loss with CineFrame. Here ¡s the thread: http://www.dvinfo.net/conf/showthrea...&postid=255005

Toke Lahti · December 20th, 2004, 06:31 PM

<<<-- Originally posted by Ignacio Rodriguez : Barry Green has demonstrated that there is resolution loss with CineFrame. -->>>

Thanks for the link. It's a bit surprising that CF's resolution is a bit better than it could theoretically be at least without any smart DI(>540 lines).
But I wasn't talking about CF, I was talking about slow shutter speeds and I haven't seen a chart with them...

Ignacio Rodriguez · December 20th, 2004, 07:06 PM

> I was talking about slow shutter speeds

Hmmm now that you mention it, so was I initially when I started this thread. But, from what I have read, it seems that when operating in CineFrame mode the shutter speed does decrease, at least Steve Mullen's article seems to suggest it. I guess it's time to read the manual.

December 16th, 2004, 08:33 PM	#17
John Jay Major Player Join Date: Sep 2002 Location: US & THEM Posts: 827	<<<-- Originally posted by Toke Lahti : <<<-- Originally posted by John Jay : its more an interlacing thing, than format. If the speed drops below the field rate than it delivers the dominant field. -->>> But is it like this with fx1? I got a quick chance to test a little a bit of my fellow workers fx1 and I also noticed that it's resolution didn't lower to half with slower shutter. I didn't have resolution charts with me or anything but we shot high resolution poster with fine print in it and monitored it with hp's L2335 monitor (with component hd connection). I didn't see any diffrence in resolution. How is this possible? Are the ccd's after all progressive? Eg. if shutter speed is 1/12 s, exposure & readout time for one field is 1/24 s, so camera has to record that one field to both fields of one frame on tape. For PAL tape mechanism has to write one field for every 1/50 s, so info from another field does not get soon enough. Recording two even fields and then two odd field would lead to 25 Hz flicker problems. So slow shutter with interlaced ccd's means always that you can use only one field. Right? -->>> If you grab a still from footage shot below 1/50 and examine it in say Photoshop with a shot at 1/50 you will see a difference... __________________ John Jay Beware *PLUGGER-BYTES*

December 17th, 2004, 04:04 PM	#19
John Jay Major Player Join Date: Sep 2002 Location: US & THEM Posts: 827	<<<-- Originally posted by Toke Lahti : Why I didn't see the diffrence with the monitor? It has a resolution of 1920x1200, so if the resolution drops to half, it should be _very_ noticable. If the resolution does not drop to half, does the camera then have progressive ccd's? Then Reel-stream mod would become very interesting... -->>> I dont know, but if you post some grabs I will attempt to answer your Q Also if it was progressive at slower shutter speed it would look like you boosted gain by 6db - did you see extra noise? __________________ John Jay Beware *PLUGGER-BYTES*

December 20th, 2004, 02:14 PM	#20
Ignacio Rodriguez Contributor Join Date: Sep 2003 Location: Santiago, Chile Posts: 932	Barry Green has demonstrated that there is resolution loss with CineFrame. Here ¡s the thread: http://www.dvinfo.net/conf/showthrea...&postid=255005 __________________ Ignacio Rodríguez in the third world. @micronauta on Twitter. Main hardware: brain, eyes, hands.

December 20th, 2004, 07:06 PM	#22
Ignacio Rodriguez Contributor Join Date: Sep 2003 Location: Santiago, Chile Posts: 932	> I was talking about slow shutter speeds Hmmm now that you mention it, so was I initially when I started this thread. But, from what I have read, it seems that when operating in CineFrame mode the shutter speed does decrease, at least Steve Mullen's article seems to suggest it. I guess it's time to read the manual. __________________ Ignacio Rodríguez in the third world. @micronauta on Twitter. Main hardware: brain, eyes, hands.

December 16th, 2004, 05:43 PM	#16
Anhar Miah Major Player Join Date: Dec 2003 Location: United Kindom, England Posts: 290	component hey? could it be that it is uncompressed signal i.e before the mpeg2 hit thus your seeing no res loss? I know this whole issuse was raised before about compressed not compressed component output, please lets not start that again..

December 17th, 2004, 06:31 AM	#18
Toke Lahti Major Player Join Date: Oct 2004 Location: Helsinki, Finland Posts: 158	<<<-- Originally posted by John Jay : If you grab a still from footage shot below 1/50 and examine it in say Photoshop with a shot at 1/50 you will see a difference... -->>> Why I didn't see the diffrence with the monitor? It has a resolution of 1920x1200, so if the resolution drops to half, it should be _very_ noticable. If the resolution does not drop to half, does the camera then have progressive ccd's? Then Reel-stream mod would become very interesting...

December 20th, 2004, 06:31 PM	#21
Toke Lahti Major Player Join Date: Oct 2004 Location: Helsinki, Finland Posts: 158	<<<-- Originally posted by Ignacio Rodriguez : Barry Green has demonstrated that there is resolution loss with CineFrame. -->>> Thanks for the link. It's a bit surprising that CF's resolution is a bit better than it could theoretically be at least without any smart DI(>540 lines). But I wasn't talking about CF, I was talking about slow shutter speeds and I haven't seen a chart with them...