DOF when using "zoom in to focus" technique at DVinfo.net

Nick Poteri · July 18th, 2004, 06:15 AM

Hi, I'm using a TRV950 for short film development. I use the following technique to focus:
(1) I zoom in to fill the frame with the subject
(2) Focus
(3) Zoom out

While this is foolproof, I'm curious how this technique might affect the depth of field. Is it the case that I will end up with a greater depth of field than if I were to focus at the original focal length without first zooming in?

Thanks,
Nick.

Jeff Donald · July 18th, 2004, 06:46 AM

The three primary factors of DOF are F Number (aperture), Distance to Subject, and Focal Length of the Lens. Your method of achieving critical focus is fine and will not effect DOF.

July 18th, 2004, 06:15 AM	#1
Nick Poteri Tourist Join Date: Jun 2003 Location: London, UK Posts: 4	DOF when using "zoom in to focus" technique Hi, I'm using a TRV950 for short film development. I use the following technique to focus: (1) I zoom in to fill the frame with the subject (2) Focus (3) Zoom out While this is foolproof, I'm curious how this technique might affect the depth of field. Is it the case that I will end up with a greater depth of field than if I were to focus at the original focal length without first zooming in? Thanks, Nick.

July 18th, 2004, 06:46 AM	#2
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	The three primary factors of DOF are F Number (aperture), Distance to Subject, and Focal Length of the Lens. Your method of achieving critical focus is fine and will not effect DOF. __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors