Fields of Depth trick?

[Patriarch]

how is it you fake a large field of depth on a video camera - ive simply forgotten something as basic as this...

I recall that the person filmed must be far away from the background, but thats about all I remember

[jbridges]

Here's a trick that I use with video. Physically take the camera as far away from the subject as you can. Then zoom in all the way to your subject. Focus on their eyes or edge of their shoulder. Then zoom out to the framing you want to have. Sometimes after this process I will take the camera back to it's original location and adjust the macro settings to really blur that background out. Just have to be careful when playing with macro, that is if your camera has that capability. Good luck. [img]wink.gif[/img]

[Nigel]

It depends on a few things...

The easiest way is to shoot only on your longer settings with a large aperature.

If you have a camera with removable lenses then you could just rent really nice long Cine lenses.

You could also try shifting the focus plane in post or with a clear filter and some grease--This will need to be tested since it may not give you what you are after. It won't change your DOF but it will look funky.

Do some searching around. P+S Technik has an adaptor that is pretty cool.

Good Luck

[m0d]

Zoom in to focal length of choice.

Adjust focus manually.

Voila!

<font color="#a62a2a" size="1">[ April 30, 2005 10:10 AM: Message edited by: m0d ]</font>

[Nigel]

Mod--

That won't change your DOF.

Good Luck

[curtinparloe]

I've heard this before, but I've never had an adequate explanation of why. I seem to remember it being something to do with the focal length not changing, but surely if you zoom, it does change...

[Nigel]

What Mod described is Critical Focus. Where you zoom in focus and then zoom out to your desired focal length. That will allow you to keep focus from the subject back toward the camera. It is the same as setting the focus with a tape measure.

The thing is if you zoom in focus and then zoom out you are still going to have the DOF of the focal length you end on. For example if you have a 25-250mm zoom and you set to focus while at 250mm but shoot at 25mm you will have to look at the DOF chart for 25mm.

The best choice for you is to shoot at longer focal lengths and move the camera back or start shooting 35.

Good Luck

[curtinparloe]

actually, that's not what he said at all [img]biggrin.gif[/img]

He was talking about shooting without zooming out again, which I understand means a different focal length. Direktyr was getting towards the Critical Focus method you describe, but not zooming out all the way, so the focal length should still be different.

I have read somewhere, however, that this doesn't work, which I found particularly confusing... [img]confused.gif[/img]

[Nigel]

Sorry, I re-read the Mod post...You are right.

Fact: Longer focal lengths decrease DOF.
Fact: Wider aperatures decrease DOF.

Video has wide DOF due to the fact that the lenses will range typically from 4-40 or something like that.

Good Luck

[Nigel]

I just assumed that he got the terms backwards. Since, everyone wants Video to be more shallow.

Good Luck