Image sharpness... at DVinfo.net

July 13th, 2002, 02:33 AM

I'm a little disappointed with the results I've been getting on my Sony PD150 when a human subject is far enough away from the camera so as to be entirely visible on screen. In the following link, http://www.rileysfarm.com/pd150test.htm, my son, Samuel looks to be in fairly good focus by my amateur standards. (He's not happy to have been part of the testing of the camera). When I zoom out, keeping manual focus on, the rest of my kids look a little pixelated and fuzzy around the edges. Do I need smaller iris? More lighting? Is that a "normal" amount of detail for a shot that far away from the subject? Any ideas would be appreciated.

Chris Hurd · July 13th, 2002, 08:14 AM

Well, all DV camcorders in general suffer from "pixel averaging" on wide angle, long distance shots. When a given subject, such as Samuel in your case, is occupying a smaller portion of the screen, there are fewer pixels available to represent him. This leads to a softening of the image. As a result, DV has never been a very good format for long distance shooting at full wide angles (wide angle is okay for close-ups and medium shots though). Sounds like a typical case of pixel averaging to me... the fix is to get closer to your subjects, or maybe try applying a sharpening filter when you're editing this material. Hope this helps,

July 13th, 2002, 11:15 AM

I'll be interested to take a look at some of these Sundance film festival winners (Tadpole, Personal Velocity) that were shot on the PD150 to see how they handle longer range shots of human subjects. Is there any place on the web you can buy DVD or VHS copies of independent films, listed by the kind of cameras used to make them?

The man of a thousand questions signing off...

Mike Rehmus · July 13th, 2002, 11:24 AM

Looks fairly good to me. Long shots are not the strength of video. You only have 720 by 480-odd pixels to represent the image. Your son, who probably subtends, lets be generous, 1/10th of the picture, has to be represented by 72 x 48 pixels or around 3500 pixels. Not very many. It is not surprising that edge detail will exhibit stairstepping and other resolution-deficiency artifacts.

July 13th, 2002, 02:33 AM	#1
JimRiley Posts: n/a	Image sharpness... I'm a little disappointed with the results I've been getting on my Sony PD150 when a human subject is far enough away from the camera so as to be entirely visible on screen. In the following link, http://www.rileysfarm.com/pd150test.htm, my son, Samuel looks to be in fairly good focus by my amateur standards. (He's not happy to have been part of the testing of the camera). When I zoom out, keeping manual focus on, the rest of my kids look a little pixelated and fuzzy around the edges. Do I need smaller iris? More lighting? Is that a "normal" amount of detail for a shot that far away from the subject? Any ideas would be appreciated.

July 13th, 2002, 08:14 AM	#2
Chris Hurd Obstreperous Rex Join Date: Jan 2001 Location: San Marcos, TX Posts: 27,368 Images: 513	Well, all DV camcorders in general suffer from "pixel averaging" on wide angle, long distance shots. When a given subject, such as Samuel in your case, is occupying a smaller portion of the screen, there are fewer pixels available to represent him. This leads to a softening of the image. As a result, DV has never been a very good format for long distance shooting at full wide angles (wide angle is okay for close-ups and medium shots though). Sounds like a typical case of pixel averaging to me... the fix is to get closer to your subjects, or maybe try applying a sharpening filter when you're editing this material. Hope this helps, __________________ CH Search DV Info Net \| 20 years of DVi \| ...Tuesday is Soylent Green Day!

July 13th, 2002, 11:15 AM	#3
JimRiley Posts: n/a	Human subjects.. I'll be interested to take a look at some of these Sundance film festival winners (Tadpole, Personal Velocity) that were shot on the PD150 to see how they handle longer range shots of human subjects. Is there any place on the web you can buy DVD or VHS copies of independent films, listed by the kind of cameras used to make them? The man of a thousand questions signing off...

July 13th, 2002, 11:24 AM	#4
Mike Rehmus Wrangler Join Date: May 2002 Location: Vallejo, California Posts: 4,049	Looks fairly good to me. Long shots are not the strength of video. You only have 720 by 480-odd pixels to represent the image. Your son, who probably subtends, lets be generous, 1/10th of the picture, has to be represented by 72 x 48 pixels or around 3500 pixels. Not very many. It is not surprising that edge detail will exhibit stairstepping and other resolution-deficiency artifacts. __________________ Mike Rehmus Hey, I can see the carrot at the end of the tunnel!