anyone know whats the diff between shutter25 and the 25f mode? at DVinfo.net

Dominik Gehring · September 7th, 2007, 07:59 AM

(or 24, 24f in NTSC land) except the fact that you can switch the shutter speed of course in the 25fmode? looks like they loose same mount of resolution compared to 1080i. (noticable in fine diagonals in wideangle, or red objects)

regards - dom

Richard Hunter · September 7th, 2007, 06:51 PM

Hi Dom. Not sure why you are seeing these as giving similar results, cos they refer to quite different features.

25f is the A1's equivalent of progressive scan. Because the CCDs are not true progressive, there is a slight loss of vertical resolution compared with 50i mode, but most people can't see this unless specifically testing for it. How are you viewing the video - is it direct from the cam, or via an NLE? If NLE, check your project settings in case the clips are somehow getting deinterlaced unnecessarily.

1/25s is the shutter speed, which is actually the amount of time the CCDs collect light before the A/D conversion is carried out. 1/25s is a bit slow for normal shooting, and I would recommend you use 1/50s instead. I'm surprised you see a loss of resolution with 1/25s, I'd expect motion blur rather than that. Maybe you could post some sample frame grabs?

Richard

Bill Pryor · September 7th, 2007, 09:51 PM

Some cameras lose resolution at slower shutter speeds. I've never shot with anything on the Canon other than the standard speed, which for 25F is 1/50, and 1/48 for 24F.

September 7th, 2007, 07:59 AM	#1
Dominik Gehring New Boot Join Date: Aug 2007 Location: Zurich / Zug - Switzerland Posts: 17	anyone know whats the diff between shutter25 and the 25f mode? (or 24, 24f in NTSC land) except the fact that you can switch the shutter speed of course in the 25fmode? looks like they loose same mount of resolution compared to 1080i. (noticable in fine diagonals in wideangle, or red objects) regards - dom

September 7th, 2007, 06:51 PM	#2
Richard Hunter Trustee Join Date: Dec 2004 Location: Lipa City Batangas, Philippines Posts: 1,110	Hi Dom. Not sure why you are seeing these as giving similar results, cos they refer to quite different features. 25f is the A1's equivalent of progressive scan. Because the CCDs are not true progressive, there is a slight loss of vertical resolution compared with 50i mode, but most people can't see this unless specifically testing for it. How are you viewing the video - is it direct from the cam, or via an NLE? If NLE, check your project settings in case the clips are somehow getting deinterlaced unnecessarily. 1/25s is the shutter speed, which is actually the amount of time the CCDs collect light before the A/D conversion is carried out. 1/25s is a bit slow for normal shooting, and I would recommend you use 1/50s instead. I'm surprised you see a loss of resolution with 1/25s, I'd expect motion blur rather than that. Maybe you could post some sample frame grabs? Richard

September 7th, 2007, 09:51 PM	#3
Bill Pryor Contributor Join Date: Jan 2003 Location: Kansas City, MO Posts: 4,449	Some cameras lose resolution at slower shutter speeds. I've never shot with anything on the Canon other than the standard speed, which for 25F is 1/50, and 1/48 for 24F.