How to focus on an object while background is out of focus? camera is moving at DVinfo.net

Tom de Boefer · August 7th, 2003, 05:38 AM

Hey all!

I have bought a trv950 and i was wondering how to focus on an object while background is out of focus? The camera is moving.

I am in manual focus mode but when i turn the focusring then everything is out of focus (or in focus)

did i miss something overhere? thx!

(i have to film around a person and the background has to be out of focus)

Tom de Boefer · August 9th, 2003, 02:07 AM

euh this can't be that difficult right??

Frank Granovski · August 9th, 2003, 02:12 AM

Open up the iris, zoom in from 10X, focus your subject. If that doesn't work, use a cam with 1/2" CCDs.

Alex Knappenberger · August 9th, 2003, 03:27 AM

Yup, Frank is right. It's called DOF (depth of field), and to get a shallow DOF with a camera with such a small surface area on the sensor(s) is nearly impossible, unless your at the long end of the lens with a fully opened Iris.

Read up on it.

Tor Salomonsen · August 9th, 2003, 12:29 PM

If you have control over the set a lot could be done with lighting, colours and choice of environment. A light fog will usually make near objects stand out dramatically against a dim background. Also, you might be able to find a filter that softens or blurs all but the central area. (Or even make one by smearing butter on a regular UV filter.)

Young Lee · August 10th, 2003, 12:31 AM

This might solve your problem.

http://www.fiercely-independent.com/...reenClips.html

Yik Kuen · August 10th, 2003, 10:52 PM

Try using the Program AE mode : Portrait.

In this mode, the cam will try to use biggest iris (F1.6 for 950) and control the shutter speed for exposure. This'll give you the shallowest DOF.

Tom de Boefer · August 11th, 2003, 03:30 AM

thx all guys, it's allready working ;-)

Tom Hardwick · August 20th, 2003, 09:40 AM

The short answer Tom is to choose some or all of the following if you want blurry backgrounds.

1) Use full telephoto
2) Use maximum aperture
3) use closest focus.
4) have the background as far away as possible.

It's as simple as that and applies whatever your chip size, focal length, frame rate, lighting conditions.

tom.

Barry Green · August 20th, 2003, 12:02 PM

Those are the rules, and they will help you get the shallowest depth of field and softest background possible under the given circumstances.

However, it should be noted that in a lot of situations it will be simply impossible to get any sort of out-of-focus background with today's video cameras, using these rules alone. For example, using a 1/4" CCD video camera in an indoors interview situation, the camera will be optically incapable of making the background soft.

For these circumstances, I've developed a product that lets you get the shallow-depth-of-field look and soft focus backgrounds. You can see it at www.softscreen.us.

August 7th, 2003, 05:38 AM	#1
Tom de Boefer New Boot Join Date: Jul 2003 Location: Belgium Posts: 8	How to focus on an object while background is out of focus? camera is moving Hey all! I have bought a trv950 and i was wondering how to focus on an object while background is out of focus? The camera is moving. I am in manual focus mode but when i turn the focusring then everything is out of focus (or in focus) did i miss something overhere? thx! (i have to film around a person and the background has to be out of focus)

August 9th, 2003, 02:07 AM	#2
Tom de Boefer New Boot Join Date: Jul 2003 Location: Belgium Posts: 8	euh this can't be that difficult right??

August 9th, 2003, 02:12 AM	#3
Frank Granovski Outer Circle Join Date: May 2002 Location: Hope, BC Posts: 7,524	Open up the iris, zoom in from 10X, focus your subject. If that doesn't work, use a cam with 1/2" CCDs.

August 9th, 2003, 03:27 AM	#4
Alex Knappenberger High School Student Join Date: Apr 2003 Location: Canton, Ohio, USA Posts: 609	Yup, Frank is right. It's called DOF (depth of field), and to get a shallow DOF with a camera with such a small surface area on the sensor(s) is nearly impossible, unless your at the long end of the lens with a fully opened Iris. Read up on it.

August 9th, 2003, 12:29 PM	#5
Tor Salomonsen Major Player Join Date: Jan 2003 Location: Stavanger, Norway Posts: 265	If you have control over the set a lot could be done with lighting, colours and choice of environment. A light fog will usually make near objects stand out dramatically against a dim background. Also, you might be able to find a filter that softens or blurs all but the central area. (Or even make one by smearing butter on a regular UV filter.)

August 10th, 2003, 12:31 AM	#6
Young Lee Major Player Join Date: Aug 2003 Location: Orange County, CA Posts: 268	This might solve your problem. http://www.fiercely-independent.com/...reenClips.html

August 10th, 2003, 10:52 PM	#7
Yik Kuen Regular Crew Join Date: Dec 2002 Location: Johor Bahru, Malaysia Posts: 135	Try using the Program AE mode : Portrait. In this mode, the cam will try to use biggest iris (F1.6 for 950) and control the shutter speed for exposure. This'll give you the shallowest DOF.

August 11th, 2003, 03:30 AM	#8
Tom de Boefer New Boot Join Date: Jul 2003 Location: Belgium Posts: 8	thx all guys, it's allready working ;-)

August 20th, 2003, 09:40 AM	#9
Tom Hardwick Inner Circle Join Date: Mar 2003 Location: Billericay, England UK Posts: 4,711	The short answer Tom is to choose some or all of the following if you want blurry backgrounds. 1) Use full telephoto 2) Use maximum aperture 3) use closest focus. 4) have the background as far away as possible. It's as simple as that and applies whatever your chip size, focal length, frame rate, lighting conditions. tom.

August 20th, 2003, 12:02 PM	#10
Barry Green Barry Wan Kenobi Join Date: Jul 2003 Location: North Carolina Posts: 3,863	Those are the rules, and they will help you get the shallowest depth of field and softest background possible under the given circumstances. However, it should be noted that in a lot of situations it will be simply impossible to get any sort of out-of-focus background with today's video cameras, using these rules alone. For example, using a 1/4" CCD video camera in an indoors interview situation, the camera will be optically incapable of making the background soft. For these circumstances, I've developed a product that lets you get the shallow-depth-of-field look and soft focus backgrounds. You can see it at www.softscreen.us.