View Full Version : The purpose behind setting the gain to -3db


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 :)