Sharpness Control at DVinfo.net

Chris Long · October 24th, 2003, 09:19 AM

What exactly does the Sharpness setting, as found in the Custom Preset menu, control? How does it do what it does?

Jeff Donald · October 24th, 2003, 10:07 AM

Usually it controls edge detail (increases contrast of edges). But unfortunately noise contained within the image is sharpened too. I turn sharpness on NTSC video down most of the way, especially on monitors.

Ignacio Rodriguez · October 24th, 2003, 12:58 PM

I turn the sharpness setting down two or three steps for a more natural look when using the built-in optics, but I turn it back up to the default when using a cheapo wide-angle adapter to compensate a bit for the softening from the low quality lens.

Julian Luttrell · October 24th, 2003, 01:59 PM

I agree with the sentiment here - I usually dial sharpness down two clicks because I find the factory default leaves rather obvious video edge effects.

Regards,

Julian

Boyd Ostroff · October 24th, 2003, 03:06 PM

Personally I turn it all the way to the minimum on my PDX-10. I dislike that over-sharpened edge look. You will also note some color fringes under high contrast situations when using the default settings, and it makes noise more noticeable in low light situations.

But it really depends on your likes and dislikes. Shoot a few seconds using different settings, playback on a monitor and decide for yourself...

Chris Long · October 24th, 2003, 05:48 PM

Thanks all! Much to explore...

Shawn Mielke · October 25th, 2003, 03:16 PM

The amount of sharpness, for me, depends on the type of shot. In well balanced lighting with little contrast, I often have sharpness turned all the way up. I just love the texture of details, as on plants, leaves, foliage, surfaces. But edges of things, trees, people, in relatively high contrast, gives away the effect being had on the image, and can make for a jaggy mess, especially with a good deal of distance from the subject. In closeups, I think it can be brilliant. Experimentation is experience is key!

Tom Hardwick · October 26th, 2003, 02:46 AM

I've played with the sharpness preset and I'd like to rename it as a softness control. Unlike you guys I find the softening left of centre unacceptable, but that could be because I've been shootiing a lot of buildings in testing the camera. The brick wall makes a very revealing subject in many ways.

tom.

Jeff Donald · October 26th, 2003, 06:01 AM

It's a trade off between a too soft image and the enhanced noise of the sharpened image. I suspect there may a difference between PAL and NTSC, as to how the sharpened image looks. I find the noise much more objectionable than the soft image.

Boyd Ostroff · October 26th, 2003, 09:56 AM

It's my belief that when you turn the sharpness all the way down you're seeing what the CCD's actually capture. The sharpening is a "filter" applied to that image in an attempt to enhance the detail. Please feel free to correct me if you have information to the contrary, but this seems to hold true for most of the digital still cameras I've used. I really don't think this control does any "softening" to the raw image.

I would prefer to get the actual CCD data onto my tape. If I think it looks too soft later (when I can view it at my leisure on a monitor back home) then it's a simple matter to apply a sharpening filter in my NLE. This will yield the same effect, possibly even with more subtle control.

But like I said before, it's all a matter of personal taste and style, and it's a good thing that we all do things a little differently or the world would be a pretty boring place ;-)

Gints Klimanis · October 27th, 2003, 02:01 PM

Boyd,

Do you know if this sharpening filter (looks like a high frequency shelf boost, to me) is at a neutral setting ( 0 dB gain) at the
middle setting or the minimum setting? On the Vx2000, the factory default is set to the middle of the range. I've seen the artifacts at max Sharpness, but I have not yet experimented with min Sharpness.

Thanks.

Jeff Donald · October 27th, 2003, 02:27 PM

The software (NLE) filter gives you much more control. However, rendering time for some people could be a real problem. I think 0 dB would not be a middle setting but lower (minus 2 or the lowest setting). The middle setting would be what the manufacture thinks looks best. But sharpening is definitely added at the middle position. Noise is also being added or enhanced at the middle setting.

Graeme Nattress · October 27th, 2003, 03:10 PM

I like the look of the PDX10 with the sharpness at a minimum. Again, it's been said that if you want sharpness after teh fact you can add it in your NLE, but you can't take it off after it's been added in the camera.

I wonder also if the DV codec will not work better on an image that has less sharpness??

Boyd Ostroff · October 27th, 2003, 04:15 PM

I tend to agree with what Jeff and Graeme say. I think the minimum sharpness setting represents the raw CCD data and you apply more of the sharpening filter as you increase it.

True, rendering time will be a factor. This seems pretty much like the same trade-offs you would experience with a physical glass filter in front of your lens. You might very well acheive the same effects in post, at the expense of rendering. But as Graeme points out, once you've recorded something filtered to tape then you don't have the option of changing your mind later.

I also think it's extremely hard to make judgements on things like sharpness based on the viewfinder and flip-out LCD. Unless you can judge an effect like this on an external monitor, or from experience with the camera, you are taking a bit of a chance. I formed my opinion on the sharpness after viewing tapes that I had made. Then to set my mind at rest, one day I hooked up an external 16:9 screen to the camera and just experimented around with the sharpness control while pointing the camera at different subjects. In pretty much all cases I liked the minimum setting the best. As you increase the sharpness you defiinitely start to see more noise, as Jeff points out. You also start to notice more fringes around the edges of high contrast objects.

However, I'm sure there may be situations where more sharpness can work in your favor, as Shawn describes. And for that matter, other people just see things with different eyes. But regardless, I think you will find any time you spend with a monitor connected to the camera well spent. This is a great way to get an understanding of what all the custom preset items do.

Gints Klimanis · October 27th, 2003, 04:49 PM

>Again, it's been said that if you want sharpness after teh fact >you can add it in your NLE, but you can't take it off after it's >been added in the camera.

Actually, you can take it off after it's been added. While it may be difficult to determine the exact filter parameters, the whole effect seems to a high frequency shelf filter which boosts frequencies above a specified frequency. The slope from the filter frequency to the shelf edge frequency will almost definitely be 6 dB/octave.
To reduce the effect, apply the opposite, which is a high frequency shelf filter with attenuation. Sure, the full signal can't be completely recovered, but most of the sharpening can be undone.

Someday, someone (yeah right) may dial into a camcorder designer for the exact specifications of the sharpening filter and how they correspond to the values in the camcorder menu.
If anyone is willing to take a picture of a black on white vertical
bar that is one CCD element wide for ten or so settings of the sharpness filter, I'll do the frequency domain analysis.

October 24th, 2003, 09:19 AM	#1
Chris Long Regular Crew Join Date: Jul 2003 Location: Middletown, Maryland USA Posts: 177	Sharpness Control What exactly does the Sharpness setting, as found in the Custom Preset menu, control? How does it do what it does?

October 24th, 2003, 10:07 AM	#2
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	Usually it controls edge detail (increases contrast of edges). But unfortunately noise contained within the image is sharpened too. I turn sharpness on NTSC video down most of the way, especially on monitors. __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors

October 24th, 2003, 12:58 PM	#3
Ignacio Rodriguez Contributor Join Date: Sep 2003 Location: Santiago, Chile Posts: 932	I turn the sharpness setting down two or three steps for a more natural look when using the built-in optics, but I turn it back up to the default when using a cheapo wide-angle adapter to compensate a bit for the softening from the low quality lens. __________________ Ignacio Rodríguez in the third world. @micronauta on Twitter. Main hardware: brain, eyes, hands.

October 25th, 2003, 03:16 PM	#7
Shawn Mielke Major Player Join Date: Jul 2003 Location: Santa Rosa, California Posts: 745	The amount of sharpness, for me, depends on the type of shot. In well balanced lighting with little contrast, I often have sharpness turned all the way up. I just love the texture of details, as on plants, leaves, foliage, surfaces. But edges of things, trees, people, in relatively high contrast, gives away the effect being had on the image, and can make for a jaggy mess, especially with a good deal of distance from the subject. In closeups, I think it can be brilliant. Experimentation is experience is key! __________________ Breakthrough In Grey Room

October 26th, 2003, 06:01 AM	#9
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	It's a trade off between a too soft image and the enhanced noise of the sharpened image. I suspect there may a difference between PAL and NTSC, as to how the sharpened image looks. I find the noise much more objectionable than the soft image. __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors

October 24th, 2003, 01:59 PM	#4
Julian Luttrell Regular Crew Join Date: Oct 2002 Location: Cambridge, UK Posts: 164	I agree with the sentiment here - I usually dial sharpness down two clicks because I find the factory default leaves rather obvious video edge effects. Regards, Julian

October 24th, 2003, 03:06 PM	#5
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,802	Personally I turn it all the way to the minimum on my PDX-10. I dislike that over-sharpened edge look. You will also note some color fringes under high contrast situations when using the default settings, and it makes noise more noticeable in low light situations. But it really depends on your likes and dislikes. Shoot a few seconds using different settings, playback on a monitor and decide for yourself...

October 24th, 2003, 05:48 PM	#6
Chris Long Regular Crew Join Date: Jul 2003 Location: Middletown, Maryland USA Posts: 177	Thanks all! Much to explore...

October 26th, 2003, 02:46 AM	#8
Tom Hardwick Inner Circle Join Date: Mar 2003 Location: Billericay, England UK Posts: 4,711	I've played with the sharpness preset and I'd like to rename it as a softness control. Unlike you guys I find the softening left of centre unacceptable, but that could be because I've been shootiing a lot of buildings in testing the camera. The brick wall makes a very revealing subject in many ways. tom.

October 26th, 2003, 09:56 AM	#10
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,802	It's my belief that when you turn the sharpness all the way down you're seeing what the CCD's actually capture. The sharpening is a "filter" applied to that image in an attempt to enhance the detail. Please feel free to correct me if you have information to the contrary, but this seems to hold true for most of the digital still cameras I've used. I really don't think this control does any "softening" to the raw image. I would prefer to get the actual CCD data onto my tape. If I think it looks too soft later (when I can view it at my leisure on a monitor back home) then it's a simple matter to apply a sharpening filter in my NLE. This will yield the same effect, possibly even with more subtle control. But like I said before, it's all a matter of personal taste and style, and it's a good thing that we all do things a little differently or the world would be a pretty boring place ;-)

October 27th, 2003, 02:01 PM	#11
Gints Klimanis Inner Circle Join Date: Jun 2003 Location: San Jose, CA Posts: 2,222	Boyd, Do you know if this sharpening filter (looks like a high frequency shelf boost, to me) is at a neutral setting ( 0 dB gain) at the middle setting or the minimum setting? On the Vx2000, the factory default is set to the middle of the range. I've seen the artifacts at max Sharpness, but I have not yet experimented with min Sharpness. Thanks.

October 27th, 2003, 02:27 PM	#12
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	The software (NLE) filter gives you much more control. However, rendering time for some people could be a real problem. I think 0 dB would not be a middle setting but lower (minus 2 or the lowest setting). The middle setting would be what the manufacture thinks looks best. But sharpening is definitely added at the middle position. Noise is also being added or enhanced at the middle setting. __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors

October 27th, 2003, 03:10 PM	#13
Graeme Nattress RED Problem Solver Join Date: Sep 2003 Location: Ottawa, Canada Posts: 1,365	I like the look of the PDX10 with the sharpness at a minimum. Again, it's been said that if you want sharpness after teh fact you can add it in your NLE, but you can't take it off after it's been added in the camera. I wonder also if the DV codec will not work better on an image that has less sharpness?? __________________ www.nattress.com - filters for FCP

October 27th, 2003, 04:15 PM	#14
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,802	I tend to agree with what Jeff and Graeme say. I think the minimum sharpness setting represents the raw CCD data and you apply more of the sharpening filter as you increase it. True, rendering time will be a factor. This seems pretty much like the same trade-offs you would experience with a physical glass filter in front of your lens. You might very well acheive the same effects in post, at the expense of rendering. But as Graeme points out, once you've recorded something filtered to tape then you don't have the option of changing your mind later. I also think it's extremely hard to make judgements on things like sharpness based on the viewfinder and flip-out LCD. Unless you can judge an effect like this on an external monitor, or from experience with the camera, you are taking a bit of a chance. I formed my opinion on the sharpness after viewing tapes that I had made. Then to set my mind at rest, one day I hooked up an external 16:9 screen to the camera and just experimented around with the sharpness control while pointing the camera at different subjects. In pretty much all cases I liked the minimum setting the best. As you increase the sharpness you defiinitely start to see more noise, as Jeff points out. You also start to notice more fringes around the edges of high contrast objects. However, I'm sure there may be situations where more sharpness can work in your favor, as Shawn describes. And for that matter, other people just see things with different eyes. But regardless, I think you will find any time you spend with a monitor connected to the camera well spent. This is a great way to get an understanding of what all the custom preset items do.

October 27th, 2003, 04:49 PM	#15
Gints Klimanis Inner Circle Join Date: Jun 2003 Location: San Jose, CA Posts: 2,222	>Again, it's been said that if you want sharpness after teh fact >you can add it in your NLE, but you can't take it off after it's >been added in the camera. Actually, you can take it off after it's been added. While it may be difficult to determine the exact filter parameters, the whole effect seems to a high frequency shelf filter which boosts frequencies above a specified frequency. The slope from the filter frequency to the shelf edge frequency will almost definitely be 6 dB/octave. To reduce the effect, apply the opposite, which is a high frequency shelf filter with attenuation. Sure, the full signal can't be completely recovered, but most of the sharpening can be undone. Someday, someone (yeah right) may dial into a camcorder designer for the exact specifications of the sharpening filter and how they correspond to the values in the camcorder menu. If anyone is willing to take a picture of a black on white vertical bar that is one CCD element wide for ten or so settings of the sharpness filter, I'll do the frequency domain analysis.