SHP setting at DVinfo.net

Lev Naumov · December 27th, 2007, 09:18 PM

Sorry for interrupting you again, but I appreciate for your help. I'm trying to make a presets for my needs and can one tell me, how SHP works. Does negative sharpness really MAKE picture blurer, or it just DOESN'T MAKE it sharper? In other words: sharpness is controlled digitally, by DSP or it influences only optics? In which position sharpness function has no influence to the picture at all: when it is -9 or when 0?

Kris Bird · December 28th, 2007, 11:41 AM

Hi Lev, good question and one I've not yet found the answer to. It should be easy enough to test with a scope (digital or analogue), by looking for sharpening artefacts... One point, though- while recording with "minimum artificial sharpening" might sound like the best solution (i.e. with the intent of sharpening to-taste in post), but there are other consequences-- how will the image be treated by the mpeg2 codec? If details are too soft then will the mpeg2 codec think it's not an edge, and de-prioritise? Also- if your goal is film-out, the last thing you want is a soft source image. Canon's "Cine" preset has sharpness turned *up*, not down! Just some points which you might already know :) I'll let you know when I've got around to testing, in regards to answering your question directly.

Lev Naumov · December 28th, 2007, 07:04 PM

Thank you beforehand.

Does anyone else can add something?

Kris Bird · December 30th, 2007, 11:15 AM

Just tested, there's definitely oversharpening/overshoot at SHP=0

Based on limited testing so far, -7 has a tiny bit of artefacting, maybe. -9 has none.

(Note: that *doesn't* mean it really doesn't sharpen at all at -9, just that over-sharpening isn't visible on my scope in front of me right now).

The amount of artefacting at -5 SHP is almost nil, I'm considering this setting for a feature film shoot I have coming up in Feb. I'm worried about losing a little detail though, since obviously when this processing is done the internal DSP has more bits to play with... so too low a SHP setting might be losing info by the time it gets truncated to 8 bits and pumped through the codec. Upshot is that I'll be shooting either -5 or above, artefacts or not.. TBC

Lev Naumov · January 4th, 2008, 05:26 AM

Thanks a lot!
But this looks strange: no artefacts on -9 and -5 and some artefacts on -7. Did I understand you right?

Kris Bird · January 4th, 2008, 06:17 AM

Sorry if my post wasn't clear-- -9 has none (to my eye), -7 was just about visible.. -5 was still 'practically nil', meaning not enough to worry me! Approaching 0 it became quite obvious/visible.

Lev Naumov · January 4th, 2008, 04:23 PM

Ok, I got it, thanks a lot.

December 27th, 2007, 09:18 PM	#1
Lev Naumov New Boot Join Date: Nov 2007 Location: Amsterdam Posts: 17	SHP setting Sorry for interrupting you again, but I appreciate for your help. I'm trying to make a presets for my needs and can one tell me, how SHP works. Does negative sharpness really MAKE picture blurer, or it just DOESN'T MAKE it sharper? In other words: sharpness is controlled digitally, by DSP or it influences only optics? In which position sharpness function has no influence to the picture at all: when it is -9 or when 0?

December 28th, 2007, 11:41 AM	#2
Kris Bird Regular Crew Join Date: Sep 2005 Location: UK Posts: 173	Hi Lev, good question and one I've not yet found the answer to. It should be easy enough to test with a scope (digital or analogue), by looking for sharpening artefacts... One point, though- while recording with "minimum artificial sharpening" might sound like the best solution (i.e. with the intent of sharpening to-taste in post), but there are other consequences-- how will the image be treated by the mpeg2 codec? If details are too soft then will the mpeg2 codec think it's not an edge, and de-prioritise? Also- if your goal is film-out, the last thing you want is a soft source image. Canon's "Cine" preset has sharpness turned up, not down! Just some points which you might already know :) I'll let you know when I've got around to testing, in regards to answering your question directly.

December 28th, 2007, 07:04 PM	#3
Lev Naumov New Boot Join Date: Nov 2007 Location: Amsterdam Posts: 17	Thank you beforehand. Does anyone else can add something?

December 30th, 2007, 11:15 AM	#4
Kris Bird Regular Crew Join Date: Sep 2005 Location: UK Posts: 173	Just tested, there's definitely oversharpening/overshoot at SHP=0 Based on limited testing so far, -7 has a tiny bit of artefacting, maybe. -9 has none. (Note: that doesn't mean it really doesn't sharpen at all at -9, just that over-sharpening isn't visible on my scope in front of me right now). The amount of artefacting at -5 SHP is almost nil, I'm considering this setting for a feature film shoot I have coming up in Feb. I'm worried about losing a little detail though, since obviously when this processing is done the internal DSP has more bits to play with... so too low a SHP setting might be losing info by the time it gets truncated to 8 bits and pumped through the codec. Upshot is that I'll be shooting either -5 or above, artefacts or not.. TBC

January 4th, 2008, 05:26 AM	#5
Lev Naumov New Boot Join Date: Nov 2007 Location: Amsterdam Posts: 17	Thanks a lot! But this looks strange: no artefacts on -9 and -5 and some artefacts on -7. Did I understand you right?

January 4th, 2008, 06:17 AM	#6
Kris Bird Regular Crew Join Date: Sep 2005 Location: UK Posts: 173	Sorry if my post wasn't clear-- -9 has none (to my eye), -7 was just about visible.. -5 was still 'practically nil', meaning not enough to worry me! Approaching 0 it became quite obvious/visible.

January 4th, 2008, 04:23 PM	#7
Lev Naumov New Boot Join Date: Nov 2007 Location: Amsterdam Posts: 17	Ok, I got it, thanks a lot.