Depth of FieldComplications Ensue
Complications Ensue:
The Crafty Screenwriting, TV and Game Writing Blog




Archives

April 2004

May 2004

June 2004

July 2004

August 2004

September 2004

October 2004

November 2004

December 2004

January 2005

February 2005

March 2005

April 2005

May 2005

June 2005

July 2005

August 2005

September 2005

October 2005

November 2005

December 2005

January 2006

February 2006

March 2006

April 2006

May 2006

June 2006

July 2006

August 2006

September 2006

October 2006

November 2006

December 2006

January 2007

February 2007

March 2007

April 2007

May 2007

June 2007

July 2007

August 2007

September 2007

October 2007

November 2007

December 2007

January 2008

February 2008

March 2008

April 2008

May 2008

June 2008

July 2008

August 2008

September 2008

October 2008

November 2008

December 2008

January 2009

February 2009

March 2009

April 2009

May 2009

June 2009

July 2009

August 2009

September 2009

October 2009

November 2009

December 2009

January 2010

February 2010

March 2010

April 2010

May 2010

June 2010

July 2010

August 2010

September 2010

October 2010

November 2010

December 2010

January 2011

February 2011

March 2011

April 2011

May 2011

June 2011

July 2011

August 2011

September 2011

October 2011

November 2011

December 2011

January 2012

February 2012

March 2012

April 2012

May 2012

June 2012

July 2012

August 2012

September 2012

October 2012

November 2012

December 2012

January 2013

February 2013

March 2013

April 2013

May 2013

June 2013

July 2013

August 2013

September 2013

October 2013

November 2013

December 2013

January 2014

February 2014

March 2014

April 2014

May 2014

June 2014

July 2014

August 2014

September 2014

October 2014

November 2014

December 2014

January 2015

February 2015

March 2015

April 2015

May 2015

June 2015

August 2015

September 2015

October 2015

November 2015

December 2015

January 2016

February 2016

March 2016

April 2016

May 2016

June 2016

July 2016

August 2016

September 2016

October 2016

November 2016

December 2016

January 2017

February 2017

March 2017

May 2017

June 2017

July 2017

August 2017

September 2017

October 2017

November 2017

December 2017

January 2018

March 2018

April 2018

June 2018

July 2018

October 2018

November 2018

December 2018

January 2019

February 2019

November 2019

February 2020

March 2020

April 2020

May 2020

August 2020

September 2020

October 2020

December 2020

January 2021

February 2021

March 2021

May 2021

June 2021

November 2021

December 2021

January 2022

February 2022

August 2022

September 2022

November 2022

February 2023

March 2023

April 2023

May 2023

July 2023

September 2023

November 2023

January 2024

February 2024

June 2024

September 2024

October 2024

 

Thursday, April 12, 2007

Q. What does ccd size have to do with dof? dof is a function of the lens, no?
The lens focuses light onto the image plane. A smaller CCD gives you a smaller image plane, which gives you the same effect as a smaller aperture.
Q. Check this out.
Or maybe I'm misinformed. Can someone straighten us out?

Labels:

4 Comments:

Depth-of-field is a function of aperture width to image-surface width (that is, the width of the lens opening to the size of the ccd sensor). The length of your lens does not change dof, but it makes it more visible in the final image (because you are, in essense, zooming in on the same image as you zoom your lens).
The reason small ccd cameras exhibit less dof is because they have roughly the same width lens as the larger ccd cameras--that is, for a given lens/aperture width, increasing the size of your ccd increases the perceived dof. This is the same reasoning as the reverse--for the same ccd, increasing the aperture (f-stop) will increase the dof.
Lastly, the Redrock M2 works by using standard 35mm lenses (even still camera lenses) and projecting them onto a frosted glass plate of 35mm size. Your video camera is just taking a picture of that glass, not of anything out in the real world, so to speak.
Clear as mud?
By the way, I just finished "Crafty TV Writing" and loved it!

By Blogger rjreimer, at 9:01 AM  

Thanks, Bob!

Actually that's quite clear.

And a clever work-around the Redrock folks have come up with.

By Blogger Alex Epstein, at 9:13 AM  

Disclaimer: as my son has smartaleced (sp?) back to me: "If you bigger, you actually mean smaller, well, then yes."
To the point: I am using depth-of-field ( = depth of focus) in an opposite kind of way. A "lot of dof" means the picture is sharp from here to infinity. I am using the same term to actually mean "clearly visible issues with focus, as in some parts are sharp, so are blurry."
So, yes.
The explaination stands -- it's my use of the term that was a bit reversed. Mea culpa.

By Blogger rjreimer, at 10:50 AM  

A couple further notes:

A shallow depth of field (part of the image in focus, but part not) is associated with a "filmic look" and you can really isolate your subject matter, make it pop from the background.

The bigger the CCD or CMOS, the shallower your depth of field. Since you can't make your CCDs or CMOSs bigger, the only conventional way to affect your depth of field to make it shallower is to open you Iris, or aperture up. Plan your lighting for this. If it's already pretty bright and you can't control it, you can cheat and snap your Neutral Density Filter into place, or even throw a polarizer on.

Changing your Zoom WILL NOT affect your depth of field, but it does make it look like it. Back your Cam up, and Zoom in. Also, work with the space of your Subject in relation to background. If your background is really far away, it will blur...or try to move your subject closer to the background, but move your camera farther away. Your mileage may vary.

35 mm adaptors like the REDROCK or Go35 are cool, but they add hassles ranging from really having to watch your focus, to your image being upside down.

Not all shots need a shallow dof, (though it is awesome in most contexts). Remember, on Citizen Cane they went out of their way to ensure that everything was in focus.

I know some of these points were re-iterated, but I wanted this post to be as un-cryptic as possible.

BTW: I just started on Crafty TV writing. digging it so far.

By Blogger Tim, at 5:17 AM  

Post a Comment

Back to Complications Ensue main blog page.



This page is powered by Blogger.