Depth of Field - Complications Ensue
Complications Ensue:
The Crafty TV and Screenwriting Blog




Baby Name Voyager graphs baby name frequency by decade.

Social Security Administration: Most popular names by year.

Name Trends: Uniquely popular names by year.

Reverse Dictionary Search: "What's that word that means....?"

Facebook Name Trees Match first names with last names.


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

 

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 bob, 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 bob, 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.