DV Info Net

DV Info Net (https://www.dvinfo.net/forum/)
-   Canon VIXIA Series AVCHD and HDV Camcorders (https://www.dvinfo.net/forum/canon-vixia-series-avchd-hdv-camcorders/)
-   -   reduce depth of field on Canon HV20 (https://www.dvinfo.net/forum/canon-vixia-series-avchd-hdv-camcorders/120789-reduce-depth-field-canon-hv20.html)

Steve Brady September 29th, 2007 12:08 PM

1 Attachment(s)
Quote:

Originally Posted by Robert Ducon (Post 751752)
Even then Steve, Pieter is right. The fully open Iris on the HV20 is still shaped like a diamond - it only consists of four-blades. So Pieter, that's the best you'll get! And, it's not bad, really.

Like I said, the trick is to lock the aperture with the camera zoomed out fully. If you lock the aperture with the camera zoomed in at all, you can't get a fully open iris. This is straight out of my camera (it's the Num Lock light on my keyboard):

Robert Ducon September 29th, 2007 06:19 PM

I stand corrected! Now that I think of it, I've gotten an image similar to that too, but the focus was so far out that it was just pretty colours (shot at night, street lights, etc).

Pieter Jongerius September 30th, 2007 06:06 AM

Hi Steve&Robert,
thanks voor 'zooming in' on my relatively OT statement there. Helps me a lot!
Pieter
(ps - and I learned a new word: bokeh ;)

Loney Childress October 18th, 2007 08:54 AM

I too would love to be able to do DOF effects more naturally, but it costs so dang much. In a short movie I made (before buying my HV20) I did the green screen trick. I think it looks alright.

Here's a link, not to my movie but a short demo of some of the effects in my movie. You'll see one is a DOF effect using green screen. I don't think it looks half bad.

http://youtube.com/watch?v=AXec4XjmtHE

Rob Gregory-Browne October 24th, 2007 09:49 PM

For anyone who gets hung up on depth of field, I urge you to see Orson Welles's Touch of Evil.

Michael Jouravlev October 25th, 2007 12:30 AM

Zooming in does not produce shallower DOF if the subject takes up the same portion of the screen.

Chris Hurd October 25th, 2007 07:24 AM

Actually yes, technically this is indeed true. Zooming in will in fact produce a shallower depth of field. However this technique for decreasing depth of field is not all that useful because the subject size obviously changes as focal length changes. For a full explanation, see our definitive article "The Ultimate Depth-of-Field Skinny" by Jeff Donald, located at http://www.dvinfo.net/articles/optics/dofskinny.php -- hope this helps,

Daniel Browning October 25th, 2007 10:13 PM

You are both correct.

Quote:

Originally Posted by Michael Jouravlev (Post 764393)
Zooming in does not produce shallower DOF if the subject takes up the same portion of the screen.

Michael, you're saying that DoF does not change if the operator moves the camera so that the framing is the same, no matter the focal length.

Quote:

Originally Posted by Chris Hurd (Post 764512)
Zooming in will in fact produce a shallower depth of field...[but]...the subject size changes as focal length changes.

Chris, you're saying that the DoF will change if the operateor does not move the camera.

It's important to note the difference, because if a shot is framed the same way at wide angle and telephoto, the telephoto shot will yeild more diffuse background blur due to magnification, even though the DoF is the same.

Brad Mirman November 19th, 2007 11:53 AM

DOF Test
 
I did a quick test on DOF for the HV 20. You can view it here:

http://www.vimeo.com/393169

Make sure to select Full Screen to see detail.

Hope it helps.

Brad

Rob Gregory-Browne November 19th, 2007 03:53 PM

Hey, Brad, thanks for the DOF test on the HV20. The image is gorgeous.

I'm curious -- are you the same Brad Mirman who wrote Resurrection? One of the creepiest serial killer movies of all time.

rgb


All times are GMT -6. The time now is 02:06 AM.

DV Info Net -- Real Names, Real People, Real Info!
1998-2024 The Digital Video Information Network