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Reducing Depth of Field on an XL-H1

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stevenerie
Reducing Depth of Field on an XL-H1
on Jul 16, 2007 at 8:39:10 pm

Hello,

I am trying to create a shot where my foreground character is in focus with a soft (out of focus) background. I'm shooting 24f and have tried the built-in ND filters. I'm using the manual focus ring.

What can I do to pull this off?

Thanks!

-Steve


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Todd at Fantastic Plastic
Re: Reducing Depth of Field on an XL-H1
on Jul 17, 2007 at 3:33:59 am

Unfortunately as has been discussed many times on this and other forums like cinematography... it is very VERY difficult (often nearing impossible) to get shallow depths of field with most any camcorder. Even with a larger 2/3" sensor camcorder DoF is going to be very deep, and with the small 1/3" sensors on your XLH1 it is going to be even tougher.

It's just principals of physics and optics which really can't be bent. The smaller the "target area" of the image (the sensor), the deeper DoF will naturally be. And 1/3" is very small. It's exactly the same reason that 16mm film has much deeper DoF compared to 35mm film, given similar focal lengths and f-stops.

There are a couple of things that you can try:

1) Use as long a focal length as your shot will allow (i.e., get as far away from your subject as possible and zoom in as much as you can.

2) Make sure you are shooting "wide open" with the largest f-stop possible. And make sure you are shooting with 0dB gain (or -3dB if the lighting will allow), and open up the iris manually as much as possible. If you are overexposing, use the lens' built-in ND filters to cut it, or for a little more finesse use external front-of-lens neutral density filters. Resist the urge to tweak exposure by varying shutter speed... if you have to, you can adjust it a little, but when shooting 24f you should keep at as close to 1/48th as possible if you want "normal" appearing action (go slower and images will smear, go faster and action will begin to look choppy, like film shot with a narrow-degree shutter).

If you do those two things, you will minimize the depth of field as much as the XLH1 (or any similar camera) will allow. Deep background and extreme foreground objects may have some softness, it might be enough for your particular application.

To get true shallow DoF with the XLH1, the best results come from ditching the stock lens and putting on a 35mm depth-of-field converter, and use cine prime lenses (or still camera lenses will also work, although they are more difficult to use). There are a half dozen or so different DoF converters... ranging from the cheapest which is probably the Letus35 at a few hundred bucks... up to the "Rolls Royce" of converters with is the P+S Technik Mini35 coming in more in the 10 grand neighborhood. They all work pretty much in the same way, but you tend to get what you pay for.

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com






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stevenerie
Re: Reducing Depth of Field on an XL-H1
on Jul 17, 2007 at 11:14:44 am

T2,

Wow! Thank you for that VERY CLEAR explanation!

The news doesn't sound good thought. I will look into a lense system, but I am going to shoot a sample shot and run it thru AE using the new Andrew Cramer tutorial to see if I can fake it in post.

Again, thank you for taking the time to respond so quickly and clearly!!

-Steve


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Frank Tucker
Re: Reducing Depth of Field on an XL-H1
on Jul 17, 2007 at 7:30:33 pm

One other though is to use all of Todd's explanation and also move your subject as far away from the background objects that might be in focus as possible. I have discovered that when shooting outdoors where distance is more easily adjusted, I can achive the effect with a tight zoom and a background separation of about 30 feet or more.

If possible place your subject at least 25-30 feet from the nearest object that will be in the shot. Move as far back as possible and frame with the extended zoom. Use Todd's methods to achive the rest and the results can be quit good. This is much harder to achive indoors in most shooting situation unless you are shooting in a large building where you can achive these distances.

Hope this helps.

Copter Doc
The spin starts here (;->)


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Videomac
Re: Reducing Depth of Field on an XL-H1
on Jul 18, 2007 at 11:10:08 pm

I have used the Optex XL to PL ($695)converter and used a couple of lens a 10mm, 18mm and a 50 from 16mm and a 25-250 Cooke in 35mm in a XL-2 (all the images are multiplied from 7x to 9x depending on the lens) a cheaper way to go but I don't know if it will work on the XL HD



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AlexHuber69
Re: Reducing Depth of Field on an XL-H1
on Jul 19, 2007 at 3:35:30 am

Sorry, but no...

Don't want to be a downer but that doesn't work.

What mount converters like the Optex do is let you replace the lens on your video camera with a real PL mount cinema lens, which most likely will be a much better lens than the stock glass which comes on the camera.

They are a great way to utilize high quality professional lenses on a consumer or prosumer camera.

However they do NOT reproduce a cinema camera's depth of field. In fact they do nothing to affect depth of field whatsoever, it will be exactly the same as before. You will probably get better picture compared to a cheap stock video lens, but the depth of field for any given f-stop setting will be EXACTLY the same. As was pointed out earlier in the thread depth of field is a function of the size of the sensor and just changing to a PL mount doesn't do anything to change that.

To emulate 35mm depth of field you need a depth of field lens adapter like the P&S Technik or one of the cheaper ones (Movietube, Letus35, Brevis35, Redrock micro, etc).

A.



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