Black stretch to increase lattitude? Main difference between FX1 and Z1? at DVinfo.net

Ignacio Rodriguez · February 10th, 2005, 09:14 AM

Today my local Sony rep read an article I wrote which mentioned the FX1/Z1 and it's shortcomings, one of which I understand is lattitude. This comes from comparison pictures I have seen of the FX1 versus XL2 and DVX100. He quickly wrote me a note suggesting that, because the Z1 has configurable black stretch, lattitude can be enhanced. Is this to be believed?

By the way if you can read spanish the article is located at http://www.canal.cl/0004.htm.

Christopher C. Murphy · February 10th, 2005, 09:28 AM

Can you translate it for us?

Douglas Spotted Eagle · February 10th, 2005, 09:29 AM

Not quite to be believed, no.
Black stretch will give the *appearance* of greater latitude, but it doesn't in fact, give you greater latitude. Black stretch is wonderful in low light or where you've got lots of dynamic range requirement. I've got shots of cheerleaders with bright halogens directly behind them, and while the halogens are not blown out to the point of zero detail, the cheerleader is lit well. Then surrounding her is black night sky. Without black stretch, I've got gradients appearing in the sky, but with black stretch on, the sky is a smooth, noise-free sky in the middle of some very extreme colors and luma values.
One caution of black stretch, it does tend to slightly desaturate very rich colors. I particularly noticed it in reds and middle blues.

David Cherniack · February 10th, 2005, 09:37 AM

Spot,

If you grade the desatuated colors in post does it increase noise?

David

Douglas Spotted Eagle · February 10th, 2005, 09:56 AM

No, but that's commenting with my eye, not commenting based on a scope. The stuff I'm talking about though, we projected on to a 20' screen, and still were just blown away by the quality.

David Cherniack · February 10th, 2005, 10:26 AM

So would you recommend black stretch for alll or most low light shooting?

Ignacio Rodriguez · February 10th, 2005, 10:39 AM

> Black stretch will give the *appearance* of greater latitude,
> but it doesn't in fact, give you greater latitude.

I see. Well I don't see... but I understand. So it's more like a gamma control... that you can use in the camera to control the image much as you would in post, with the advantage of doing it before compression. But it will not get more information into the image, formally speaking, right?

> Can you translate it for us?

I could translate the article, but most of what is mentioned in it is stuff that has been extensively discussed in the forum and covered in much more detail by Steve Mullen and others. It's an article intended for a less educated audience. I wrote as a way to impress my potential clients <grin>.

I do express my opinion about the shorcomings I see in FX1/Z1 comparing it to the DVX100, XL2 and PD170. Mainly low-light response, which is an issue with documentary work of the type I do, where you don't carry around lighting. I use a PDX10 so I know how a pain it can be to not have enough sensitivity, and I want my next cam to be far more sensitive than the PDX10, which the FX1/Z1 is not.

I also mention the potential problems with tape drops and the MPEG2 GOP structure. This is scary stuff and I don't know if the new Sony tapes will be that much better.

But the article doesn't slam the camera. It actually talks about how the introduction of HDV can be as important as the introduction of DV. Whatever the shortcomings, I think the FX1/Z1 will be of great use in the hands of indie filmakers.

I do not mention it in the article, but I think we owe the camera's quality and price point to JVC who really scared Sony into rushing it to market.

Mike Tiffee · February 10th, 2005, 10:43 AM

Translated link:

http://translate.google.com/translat...language_tools

Christopher C. Murphy · February 10th, 2005, 10:50 AM

Cool, thanks..

Ignacio Rodriguez · February 10th, 2005, 10:54 AM

The translation is so weird to read!

I see now that there is a mistake in the article: the loss of a GOP should of course result in the loss of half a second, not a full second.

February 10th, 2005, 09:14 AM	#1
Ignacio Rodriguez Contributor Join Date: Sep 2003 Location: Santiago, Chile Posts: 932	Black stretch to increase lattitude? Main difference between FX1 and Z1? Today my local Sony rep read an article I wrote which mentioned the FX1/Z1 and it's shortcomings, one of which I understand is lattitude. This comes from comparison pictures I have seen of the FX1 versus XL2 and DVX100. He quickly wrote me a note suggesting that, because the Z1 has configurable black stretch, lattitude can be enhanced. Is this to be believed? By the way if you can read spanish the article is located at http://www.canal.cl/0004.htm. __________________ Ignacio Rodríguez in the third world. @micronauta on Twitter. Main hardware: brain, eyes, hands.

February 10th, 2005, 09:28 AM	#2
Christopher C. Murphy Trustee Join Date: Sep 2003 Location: Boston, MA Posts: 1,707	Can you translate it for us? __________________ Christopher C. Murphy Director, Producer, Writer

February 10th, 2005, 09:29 AM	#3
Douglas Spotted Eagle VASST Join Date: Jan 2004 Location: Stockton, UT Posts: 5,648	Not quite to be believed, no. Black stretch will give the appearance of greater latitude, but it doesn't in fact, give you greater latitude. Black stretch is wonderful in low light or where you've got lots of dynamic range requirement. I've got shots of cheerleaders with bright halogens directly behind them, and while the halogens are not blown out to the point of zero detail, the cheerleader is lit well. Then surrounding her is black night sky. Without black stretch, I've got gradients appearing in the sky, but with black stretch on, the sky is a smooth, noise-free sky in the middle of some very extreme colors and luma values. One caution of black stretch, it does tend to slightly desaturate very rich colors. I particularly noticed it in reds and middle blues. __________________ Douglas Spotted Eagle/Spot Author, producer, composer Certified Sony Vegas Trainer http://www.vasst.com

February 10th, 2005, 09:56 AM	#5
Douglas Spotted Eagle VASST Join Date: Jan 2004 Location: Stockton, UT Posts: 5,648	No, but that's commenting with my eye, not commenting based on a scope. The stuff I'm talking about though, we projected on to a 20' screen, and still were just blown away by the quality. __________________ Douglas Spotted Eagle/Spot Author, producer, composer Certified Sony Vegas Trainer http://www.vasst.com

February 10th, 2005, 10:39 AM	#7
Ignacio Rodriguez Contributor Join Date: Sep 2003 Location: Santiago, Chile Posts: 932	> Black stretch will give the appearance of greater latitude, > but it doesn't in fact, give you greater latitude. I see. Well I don't see... but I understand. So it's more like a gamma control... that you can use in the camera to control the image much as you would in post, with the advantage of doing it before compression. But it will not get more information into the image, formally speaking, right? > Can you translate it for us? I could translate the article, but most of what is mentioned in it is stuff that has been extensively discussed in the forum and covered in much more detail by Steve Mullen and others. It's an article intended for a less educated audience. I wrote as a way to impress my potential clients <grin>. I do express my opinion about the shorcomings I see in FX1/Z1 comparing it to the DVX100, XL2 and PD170. Mainly low-light response, which is an issue with documentary work of the type I do, where you don't carry around lighting. I use a PDX10 so I know how a pain it can be to not have enough sensitivity, and I want my next cam to be far more sensitive than the PDX10, which the FX1/Z1 is not. I also mention the potential problems with tape drops and the MPEG2 GOP structure. This is scary stuff and I don't know if the new Sony tapes will be that much better. But the article doesn't slam the camera. It actually talks about how the introduction of HDV can be as important as the introduction of DV. Whatever the shortcomings, I think the FX1/Z1 will be of great use in the hands of indie filmakers. I do not mention it in the article, but I think we owe the camera's quality and price point to JVC who really scared Sony into rushing it to market. __________________ Ignacio Rodríguez in the third world. @micronauta on Twitter. Main hardware: brain, eyes, hands.

February 10th, 2005, 09:37 AM	#4
David Cherniack Regular Crew Join Date: Sep 2003 Location: Toronto Posts: 186	Spot, If you grade the desatuated colors in post does it increase noise? David

February 10th, 2005, 10:26 AM	#6
David Cherniack Regular Crew Join Date: Sep 2003 Location: Toronto Posts: 186	So would you recommend black stretch for alll or most low light shooting?

February 10th, 2005, 10:43 AM	#8
Mike Tiffee Regular Crew Join Date: Oct 2004 Posts: 150	Translated link: http://translate.google.com/translat...language_tools

February 10th, 2005, 10:50 AM	#9
Christopher C. Murphy Trustee Join Date: Sep 2003 Location: Boston, MA Posts: 1,707	Cool, thanks.. __________________ Christopher C. Murphy Director, Producer, Writer

February 10th, 2005, 10:54 AM	#10
Ignacio Rodriguez Contributor Join Date: Sep 2003 Location: Santiago, Chile Posts: 932	The translation is so weird to read! I see now that there is a mistake in the article: the loss of a GOP should of course result in the loss of half a second, not a full second. __________________ Ignacio Rodríguez in the third world. @micronauta on Twitter. Main hardware: brain, eyes, hands.