Getting the background out of focus. at DVinfo.net

Warren Harper · May 25th, 2004, 04:54 AM

I'm working with the Canon xl1s and I need to film a shot where the foreground is in focus (obviously) but I need the background to be heavily out of focus, not just a little of focus. Are there any special settings / techniques to achive this using the xl1s?

Dylan Couper · May 25th, 2004, 07:33 AM

Besides what you probably already know about DOF and 1/3" CCD miniDV cameras, here are two options that will work. The first one is cheaper, and garuanteed to give you as much as you want.

1) Buy or rent a giant diffuser screen and place it behind your subject. There is a specific name for this but I can't remember it.

2) Rent a Mini35 for the day.

Ed Smith · May 25th, 2004, 07:33 AM

Hi Warren,

You need to create depth of field by adjusting the aperture and shutter. I can't remember whether the aperture should be bigger or smaller though???

Another thing that affects depth of field for camcorders is the type of lens used, and how far away from your subject.

If you are using the standard 16x lens then you will need to be quite a distance away from your subject, and then zoom into frame.

Please provide us with more info...

Charles Papert · May 25th, 2004, 08:37 AM

The item that Dylan mentions is called Softscreen. This will work great for a closeup to a medium shot that doesn't require panning. A more elaborate shot will require the use of a Mini35 as Dylan also mentioned.

Regarding Ed's notes, a larger aperture is required for minimal depth of field, along with a long focal length and short distance to the subject. The shutter is not a factor in the equation except that it can be used as the exposure control since you are keeping your aperture open. However, a "heavily" out-of-focus background is a bit of a challenge with a DV camera. There have been endless discussions on this subject here at the DV Info Net, try a search.

Mike Gamba · May 25th, 2004, 10:17 AM

I have used the Mini 35 in the past. Together with a good Prime lense you can obtain great DOF effects. They rent for aproximatelly $600 a day

Warren Harper · May 25th, 2004, 10:43 AM

Thanks guys for all your replies. This forum is great.

I think I will try messing around with the aperture a bit and see how it turns out.

Jimmy McKenzie · May 25th, 2004, 11:08 AM

This can also be done in post. As long as the subject in the foreground doesn't move much, a matte can be created in photoshop and then used as a reveal track or a track matte in your nle suite. The amount of feather when creating the black and white track matte will dictate how many pixels are used during the computerized camera blur. Simply duplicate the clip and place it above the clip in the timeline. Apply much blur to this second or duplicate clip. Then, the track matte shows only the portion of the clip you require to be blurred. This is very useful when you need to blur a section out like a face or license plate à la COPS on Fox.
The above refers to editing with premiere.

Christopher Reynolds · May 26th, 2004, 05:47 AM

hmm, how heavily are you talking here? When I open the aparture all the way then crank up the shutter speed OR use a neutral density filter, that seems to make the background indistinguishable (sp?) ND filters are good for giving shallow depth of field as explained in this article
the reason being it helps keep your scene from looking like you're shooting on the surface of the sun. basically just the aparture on the camera itself throws everything out of focus except the plane of focus...someone already said that but I thought I would elaborate since Im not one to throw away $600.00 for one day, im not so lucky to have pockets bulging with cash

Warren Harper · May 26th, 2004, 06:40 AM

Yeah, I've been messing around with the aperture and exposure settings a bit and it looks like I'll be able to get the effect I'm looking for. Thanks for all the advice :)

Josh Brusin · May 26th, 2004, 09:22 AM

look at options in post. If it's a static shot a feathered mask could work in a pinch...
complex masks are made easy by adding color to the area that will end up being blurry... then combining a quick bezier mask and a color selection will give you potentially a better mask.

Rick Bravo · May 26th, 2004, 10:36 AM

You can also add an extender to your lens. With the Canon, not only will you increase your focal length by 1 1/2 times, you will also lose approximately 1 1/2 - 2 stops in light, thus aiding you in losing depth of field.

The closer you get to your subject, the closer you have to focus...as you focus closer, the more your background goes soft, so, once you get all of your ducks in a row, aperture, nd filters, lens size, etc., a little experimentation should give you what you want.

RB

Charles Papert · May 26th, 2004, 11:48 AM

<<basically just the aparture on the camera itself throws everything out of focus except the plane of focus...someone already said that but I thought I would elaborate since Im not one to throw away $600.00 for one day, im not so lucky to have pockets bulging with cash>>

Christopher, I know you are being facetious here, but I should point out that the method you describe will result in more than four times the depth of field than is achievable with the Mini35 given the same field of view, so it's hardly throwing away money to use such a device if the budget can handle it and a very shallow depth of field is desired at less-than-telephoto focal lengths.

Steve Siegel · May 26th, 2004, 06:21 PM

This may be pretty obvious, but no one mentioned it. If you want the background really out of focus, then once you have opened the aperture as much as you can, it becomes important that the distance between you and your subject is much shorter than the distance to the background. If you are 10 feet from your subject and the background is 30 feet, you will never get the blur you want.

Charles Papert · May 27th, 2004, 07:41 PM

Good note Steve. The closer to the camera the subject is, the shorter the depth of focus (that is, the entire plane that is in focus from front to back) and thus the softer the background. The tricky part is that if you have the exact image size you seek at 10 ft (say, a medium shot), to move the subject to 5 ft and keep that size will require zooming out the camera to a wider focal length, and you are right back where you started!

Christopher Reynolds · May 28th, 2004, 10:34 AM

<<<-- Originally posted by Charles Papert : Christopher, I know you are being facetious here, but I should point out that the method you describe will result in more than four times the depth of field than is achievable with the Mini35 given the same field of view, so it's hardly throwing away money to use such a device if the budget can handle it and a very shallow depth of field is desired at less-than-telephoto focal lengths. -->>>

Charles, sorry I came off that way but I was being serious. I understand your reasoning very much and I agree with you completely. I just wanted to be sure there were other, cheaper (although not as powerful) alternatives out on the table. I am new to this and you definately know what you're doing here so I in no way meant to offend you and apologize if I came off prudent. My choice of words was obviously at fault there.

May 25th, 2004, 04:54 AM	#1
Warren Harper New Boot Join Date: May 2004 Location: Sheffield, UK Posts: 10	Getting the background out of focus. I'm working with the Canon xl1s and I need to film a shot where the foreground is in focus (obviously) but I need the background to be heavily out of focus, not just a little of focus. Are there any special settings / techniques to achive this using the xl1s?

May 25th, 2004, 07:33 AM	#2
Dylan Couper Wrangler Join Date: Jun 2002 Location: Vancouver, British Columbia Posts: 8,314	Besides what you probably already know about DOF and 1/3" CCD miniDV cameras, here are two options that will work. The first one is cheaper, and garuanteed to give you as much as you want. 1) Buy or rent a giant diffuser screen and place it behind your subject. There is a specific name for this but I can't remember it. 2) Rent a Mini35 for the day. __________________ Need to rent camera gear in Vancouver BC? Check me out at camerarentalsvancouver.com

May 25th, 2004, 07:33 AM	#3
Ed Smith Wrangler Join Date: Jan 2002 Location: Hampshire, England Posts: 1,545	Hi Warren, You need to create depth of field by adjusting the aperture and shutter. I can't remember whether the aperture should be bigger or smaller though??? Another thing that affects depth of field for camcorders is the type of lens used, and how far away from your subject. If you are using the standard 16x lens then you will need to be quite a distance away from your subject, and then zoom into frame. Please provide us with more info... __________________ Ed Smith Hampshire, UK Good things come to those who wait My Skiing web www.Frostytour.co.uk For quick answers Search dvinfo.net \| The best in the business: dvinfo.net Sponsors

May 25th, 2004, 08:37 AM	#4
Charles Papert Wrangler Join Date: Jan 2002 Location: Los Angeles, CA Posts: 6,810	The item that Dylan mentions is called Softscreen. This will work great for a closeup to a medium shot that doesn't require panning. A more elaborate shot will require the use of a Mini35 as Dylan also mentioned. Regarding Ed's notes, a larger aperture is required for minimal depth of field, along with a long focal length and short distance to the subject. The shutter is not a factor in the equation except that it can be used as the exposure control since you are keeping your aperture open. However, a "heavily" out-of-focus background is a bit of a challenge with a DV camera. There have been endless discussions on this subject here at the DV Info Net, try a search. __________________ Charles Papert www.charlespapert.com

May 25th, 2004, 10:17 AM	#5
Mike Gamba Tourist Join Date: May 2004 Location: Staten Island, NY Posts: 4	I have used the Mini 35 in the past. Together with a good Prime lense you can obtain great DOF effects. They rent for aproximatelly $600 a day __________________ Mike G.

May 25th, 2004, 10:43 AM	#6
Warren Harper New Boot Join Date: May 2004 Location: Sheffield, UK Posts: 10	Thanks guys for all your replies. This forum is great. I think I will try messing around with the aperture a bit and see how it turns out.

May 25th, 2004, 11:08 AM	#7
Jimmy McKenzie Major Player Join Date: Jan 2004 Location: Waterloo Ontario Posts: 721	This can also be done in post. As long as the subject in the foreground doesn't move much, a matte can be created in photoshop and then used as a reveal track or a track matte in your nle suite. The amount of feather when creating the black and white track matte will dictate how many pixels are used during the computerized camera blur. Simply duplicate the clip and place it above the clip in the timeline. Apply much blur to this second or duplicate clip. Then, the track matte shows only the portion of the clip you require to be blurred. This is very useful when you need to blur a section out like a face or license plate à la COPS on Fox. The above refers to editing with premiere.

May 26th, 2004, 05:47 AM	#8
Christopher Reynolds Regular Crew Join Date: May 2004 Location: North Canton, Ohio Posts: 109	hmm, how heavily are you talking here? When I open the aparture all the way then crank up the shutter speed OR use a neutral density filter, that seems to make the background indistinguishable (sp?) ND filters are good for giving shallow depth of field as explained in this article the reason being it helps keep your scene from looking like you're shooting on the surface of the sun. basically just the aparture on the camera itself throws everything out of focus except the plane of focus...someone already said that but I thought I would elaborate since Im not one to throw away $600.00 for one day, im not so lucky to have pockets bulging with cash

May 26th, 2004, 06:40 AM	#9
Warren Harper New Boot Join Date: May 2004 Location: Sheffield, UK Posts: 10	Yeah, I've been messing around with the aperture and exposure settings a bit and it looks like I'll be able to get the effect I'm looking for. Thanks for all the advice :)

May 26th, 2004, 09:22 AM	#10
Josh Brusin Major Player Join Date: Nov 2003 Location: Chicago, IL Posts: 439	look at options in post. If it's a static shot a feathered mask could work in a pinch... complex masks are made easy by adding color to the area that will end up being blurry... then combining a quick bezier mask and a color selection will give you potentially a better mask.

May 26th, 2004, 10:36 AM	#11
Rick Bravo Major Player Join Date: Sep 2003 Location: Miami, FL Posts: 574	Warren, You can also add an extender to your lens. With the Canon, not only will you increase your focal length by 1 1/2 times, you will also lose approximately 1 1/2 - 2 stops in light, thus aiding you in losing depth of field. The closer you get to your subject, the closer you have to focus...as you focus closer, the more your background goes soft, so, once you get all of your ducks in a row, aperture, nd filters, lens size, etc., a little experimentation should give you what you want. RB __________________ "The future ain't what it used to be." Yogi Berra. www.rbravo.com

May 26th, 2004, 11:48 AM	#12
Charles Papert Wrangler Join Date: Jan 2002 Location: Los Angeles, CA Posts: 6,810	<<basically just the aparture on the camera itself throws everything out of focus except the plane of focus...someone already said that but I thought I would elaborate since Im not one to throw away $600.00 for one day, im not so lucky to have pockets bulging with cash>> Christopher, I know you are being facetious here, but I should point out that the method you describe will result in more than four times the depth of field than is achievable with the Mini35 given the same field of view, so it's hardly throwing away money to use such a device if the budget can handle it and a very shallow depth of field is desired at less-than-telephoto focal lengths. __________________ Charles Papert www.charlespapert.com

May 26th, 2004, 06:21 PM	#13
Steve Siegel Major Player Join Date: Nov 2001 Location: Albuquerque, New Mexico, USA Posts: 840	This may be pretty obvious, but no one mentioned it. If you want the background really out of focus, then once you have opened the aperture as much as you can, it becomes important that the distance between you and your subject is much shorter than the distance to the background. If you are 10 feet from your subject and the background is 30 feet, you will never get the blur you want.

May 27th, 2004, 07:41 PM	#14
Charles Papert Wrangler Join Date: Jan 2002 Location: Los Angeles, CA Posts: 6,810	Good note Steve. The closer to the camera the subject is, the shorter the depth of focus (that is, the entire plane that is in focus from front to back) and thus the softer the background. The tricky part is that if you have the exact image size you seek at 10 ft (say, a medium shot), to move the subject to 5 ft and keep that size will require zooming out the camera to a wider focal length, and you are right back where you started! __________________ Charles Papert www.charlespapert.com

May 28th, 2004, 10:34 AM	#15
Christopher Reynolds Regular Crew Join Date: May 2004 Location: North Canton, Ohio Posts: 109	<<<-- Originally posted by Charles Papert : Christopher, I know you are being facetious here, but I should point out that the method you describe will result in more than four times the depth of field than is achievable with the Mini35 given the same field of view, so it's hardly throwing away money to use such a device if the budget can handle it and a very shallow depth of field is desired at less-than-telephoto focal lengths. -->>> Charles, sorry I came off that way but I was being serious. I understand your reasoning very much and I agree with you completely. I just wanted to be sure there were other, cheaper (although not as powerful) alternatives out on the table. I am new to this and you definately know what you're doing here so I in no way meant to offend you and apologize if I came off prudent. My choice of words was obviously at fault there.