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Old October 18th, 2003, 09:03 PM   #1
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Depth of Field - Canon GL2

I shooting a project probably with a Canon GL2 DV camera and want to decrease the depth of field to make the footage look more like film. I got some suggestion including using a neutral density filter. I've never used one before and was wondering what kind I should get and what other settings I will need to adjust such as the exposure setting. Is this a good ND filter to get?

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Old October 18th, 2003, 09:47 PM   #2
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Probably not strong enough. You probably need an ND8 (3 stop loss). Also you might want to read this article and if you have question, please post in this thread.
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Old October 18th, 2003, 10:17 PM   #3
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Thanks for the site

So I'd need to get a 0.8 Neutral Density filter for 55 mm lens and adjust the f-stop to a low number to acheive depth of field. I'm still a little confused, though, about what to do if the subject is moving and about how much I need to zoom in or not.
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Old October 18th, 2003, 10:55 PM   #4
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Just for clarification the "site" is the DV Info site (our site). Please be a little more specific in your confusion and post your questions in the DOF thread and I'll try and help.
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Old October 19th, 2003, 01:35 AM   #5
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So I'd take a exposure reading put on the ND filter and boost the exposure 3 stops. Then I'd open up the aperture setting the f-stop to a low number like 1.8. Can I keep the shutter speed at 1/60 or do I have to change it?
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Old October 19th, 2003, 08:18 AM   #6
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Unless you're using a handheld light meter the camera will automatically adjust the exposure. However, my preferred method would be to put the camera into Manual Mode and set the shutter speed to 1/60 and adjust the aperture by observing the Zebra Bars.

Whoops, just noticed you have a GL2. Does your camera even have manual? If not, use Shutter Priority (TV Mode) and set your shutter speed to 1/60 second. The aperture will go 3 stops lower than without the filter. If the lens isn't near wide open (F2 to F4) then use a polarizer to reduce the light an additional 1 1/2 stops. You may need to add additional filtration if you're in very sunny locations (beach).
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Old October 19th, 2003, 05:46 PM   #7
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The GL2 has a manual setting. So you're saying that I should adjust the exposure settings based on the zebra lines? I adjust the exposure until the zebra lines go away? Do I still do this with a Neutral Density lens on?

I found a 0.9 ND filter that's 58mm. The compensation when using the filter is 3 stops. If I boost the exposure 3 stops will the zebra lines go away?

I am shooting outdoors, btw. So I need a filter that reduces light. I want to focus on the subject and blur the background in some parts of my project.
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Old October 19th, 2003, 06:20 PM   #8
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Set shutter speed to 1/60th second. Adjust aperture until zebra pattern just disappears.. You will want to do some test with the zebra bars. Some people like there images a little lighter or darker than what the zebra bars will indicate. Depending on the lighting conditions you may need to add additional filtration to get your aperture wide open (F2 to F4 will yield good results).
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Old October 22nd, 2003, 11:08 AM   #9
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Clarification: you need the 58mm filter because you're talking about the size of your threads and that's the only size that will fit the GL2 without a step-down ring.

If your goal is to keep the short DOF, then you want to keep your aperture as open as possible. I shoot with the same goal without external filters all the time. Just set it to manual and put your F-stops anywhere below 4.x, the GL2 works great in the 2.x range and even 1.8 (wide open). If you're outside, hit the ND filter that's built in (I think it is 3 stops as well). Then, adjust your shutter speed appropriately, but stay in increments of 30 (like 60, 120, etc.).

Another thing, you don't necessarily want to remove the zebra stripes completely. This CAN mean youíre under-exposed. I prefer to increase the shutter until they disappear, and then step back one setting so that they are barely there. That gives you the nice bright lines on shoulders and hair.

P.S. I NEVER use anything other than manual mode, because the one thing they don't tell you is that in AV or TV mode, the GL2 uses as much GAIN as it wants, and I don't like GAIN, so my camera never leaves full manual.
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Old October 22nd, 2003, 02:52 PM   #10
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Alex: What percentage do you have your zebra stripes set to when using the disappear/bring 'em back method?

Thanks,
Huey
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Old October 22nd, 2003, 03:28 PM   #11
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You got me . . . I don't remember. I will take a look at my equipment tonight and let you know tomorrow. This is kind of a new thread though. Jeff will move us I'm sure.

Let me take this oppurtunity to say that Jeff is awesome and if you haven't read his skinny on DOF (which he linked at the top of this thread) you need to read it, then read it again.
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Old October 22nd, 2003, 08:47 PM   #12
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Thanks for the kind words Alex, all the mods at DV Info try to be as helpful as possible.

I usually set zebra bars between 70 and 90% depending on the subject. Thatís why I recommend experimenting with different settings when you have the chance.
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Old October 23rd, 2003, 08:54 AM   #13
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<<<-- Originally posted by Brian Huey : What percentage do you have your zebra stripes set -->>>

Mine's at 90 and I've rarely changed it, but like Jeff said, how you use it really depends on the situation. Check out the recent thread on "Light meters for DV camcorders" for more information on where to use these.

Last night I created some examples of some DoF shots using my GL2. I'd like to post them but I don't have a server. If anyone would like to host this jpg let me know.
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Old October 23rd, 2003, 12:53 PM   #14
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If the ND filter is not enough to allow the iris fully open (f1.6), you can increase the shutter speed to 1/120 or 1/250. It will help reducing the exposure, thus minimizing the d.o.f.

If you use the Aperture Priority (Av) mode and set the iris fully open (f1.6), the cam will adjust the shutter speed automatically for a proper exposure.

Then step back away from your subject and zoom-in on it.
Carefully focus manually on the subject and you'll see the background has blurred.
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Old October 23rd, 2003, 01:01 PM   #15
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<<<-- Originally posted by Norm Couture : If the ND filter is not enough to allow the iris fully open (f1.6), you can increase the shutter speed to 1/120 or 1/250.

If you use the Aperture Priority (Av) mode and set the iris fully open (f1.6), the cam will adjust the shutter speed automatically for a proper exposure. -->>>

1. You could do that, but rather than limiting my shutter speed possibilies, I'd rather throw on another filter. Without having to buy one, I'd throw on my polarizer. It's quite dark and will buy another 1.5 to 2 stops.

2. Yes, but AV mode will also utilize gain without your control.

Again, I captured some great examples that I can email if you'd like.
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