The purpose behind setting the gain to -3db at DVinfo.net

Shiv Kumar · August 8th, 2007, 10:11 AM

I remember seeing an excellent video posted here by someone who had recently bought the XH A1. An early morning shot in park (on his way to work). Simply incredible and inspiring!

In his post he says he always sets the gain to -3db. I'm curious as to what that gets him.

Less noise?

Don Palomaki · August 8th, 2007, 11:33 AM

Potentially somewhat less noise (of CCD thermal and dark current origins) in the image, and perhaps slightly bit less effective usable dynamic. The lower noise may be most apparent in images with large areas of shadow or low contrast, and the dynamic range may be most apparent in images with high intensity spots. Other exposure setting (e.g., using a slow shutter) may have the effect of offsetting the some of benefit of a -3 dB setting.

Whether or not -3 dB is appropriate for a give shoot is largely a matter of image content and personal preference.

Richard Hunter · August 8th, 2007, 05:07 PM

Setting -3dB also helps if you are trying for a narrow depth of field because it means you have to open the lens a bit more to compensate.

Richard

Shiv Kumar · August 9th, 2007, 01:53 AM

Don, Richard,

Thank you both for your replies. Very informative. Didn't think about the -3db trick to get more depth of field.

Richard Hunter · August 9th, 2007, 08:49 AM

Neither did I. I picked it up from a Chris Hurd post on the forum. :)

Richard

Joe Bryan · August 9th, 2007, 02:34 PM

Less depth of field actually

Shiv Kumar · August 10th, 2007, 07:37 AM

Yes, Correct :)

August 8th, 2007, 10:11 AM	#1
Shiv Kumar Major Player Join Date: Jul 2007 Location: Gainesville, VA, USA Posts: 327	The purpose behind setting the gain to -3db I remember seeing an excellent video posted here by someone who had recently bought the XH A1. An early morning shot in park (on his way to work). Simply incredible and inspiring! In his post he says he always sets the gain to -3db. I'm curious as to what that gets him. Less noise?

August 8th, 2007, 11:33 AM	#2
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,488	Potentially somewhat less noise (of CCD thermal and dark current origins) in the image, and perhaps slightly bit less effective usable dynamic. The lower noise may be most apparent in images with large areas of shadow or low contrast, and the dynamic range may be most apparent in images with high intensity spots. Other exposure setting (e.g., using a slow shutter) may have the effect of offsetting the some of benefit of a -3 dB setting. Whether or not -3 dB is appropriate for a give shoot is largely a matter of image content and personal preference. __________________ dpalomaki@dspalomaki.com

August 8th, 2007, 05:07 PM	#3
Richard Hunter Trustee Join Date: Dec 2004 Location: Lipa City Batangas, Philippines Posts: 1,110	Setting -3dB also helps if you are trying for a narrow depth of field because it means you have to open the lens a bit more to compensate. Richard

August 9th, 2007, 01:53 AM	#4
Shiv Kumar Major Player Join Date: Jul 2007 Location: Gainesville, VA, USA Posts: 327	Don, Richard, Thank you both for your replies. Very informative. Didn't think about the -3db trick to get more depth of field.

August 9th, 2007, 08:49 AM	#5
Richard Hunter Trustee Join Date: Dec 2004 Location: Lipa City Batangas, Philippines Posts: 1,110	Neither did I. I picked it up from a Chris Hurd post on the forum. :) Richard

August 9th, 2007, 02:34 PM	#6
Joe Bryan Regular Crew Join Date: Oct 2006 Location: Alabama Posts: 31	Less depth of field actually

August 10th, 2007, 07:37 AM	#7
Shiv Kumar Major Player Join Date: Jul 2007 Location: Gainesville, VA, USA Posts: 327	Yes, Correct :)