Bokeh-Focus-Object Shrinkage Effect? at DVinfo.net

Go Back   DV Info Net > The Tools of DV and HD Production > Open DV Discussion

Open DV Discussion
For topics which don't fit into any of the other categories.


Reply
 
Thread Tools Search this Thread
Old September 26th, 2015, 09:43 AM   #1
Regular Crew
 
Join Date: Jul 2007
Location: Ft Myers, Florida
Posts: 65
Bokeh-Focus-Object Shrinkage Effect?

Ok, so OCD is acting up and trying to find this is driving me nuts. What is the specific name of the effect when the apparent size/outline of an object out-of-focus (blur, bokeh, blah) seems to appear larger than it really is when it actually comes into focus? The effect is subtle, and it isn't a much-covered subject. I learned about it years ago ... just can't remember the name of the effect. Anybody?
Rob Johnson is offline   Reply With Quote
Old September 27th, 2015, 09:44 PM   #2
Inner Circle
 
Join Date: Feb 2007
Location: Tucson AZ
Posts: 2,206
Re: Bokeh-Focus-Object Shrinkage Effect?

Maybe you're thinking of Focus Breathing???? Google it and see if it's what you're thinking of. Basically image size changing as you focus.
Jim Andrada is offline   Reply With Quote
Old September 28th, 2015, 02:02 AM   #3
Major Player
 
Join Date: Nov 2010
Location: Northridge, CA
Posts: 280
Re: Bokeh-Focus-Object Shrinkage Effect?

I think you're talking about bokeh. The way objects look in the out of focus areas. I have no idea if there's a specific term regarding the size. Just the correlation of iris, focus distance and lens length to how out-of-focus the background will be.

For example, (from Philip Bloom's speedbooster test.)

Large OOF objects:
http://philipbloom.net/blog/wp-conte...S-670x376.jpeg

Small OOF objects as focus goes closer to them:
http://philipbloom.net/blog/wp-conte...4-670x376.jpeg
Matt Sharp is offline   Reply With Quote
Old September 28th, 2015, 03:44 PM   #4
Inner Circle
 
Join Date: May 2005
Location: Burnaby, BC, Canada
Posts: 2,963
Re: Bokeh-Focus-Object Shrinkage Effect?

It does sound like lens breathing. Cheaper manual focus lens tend to breathe when rack focusing. It gives the illusion that the object is larger when in fact the entire frame is pushed in when the focus "breathes"

High end productions don't like lens breathing, which is why PL lenses in the higher price range rarely focus breathe. If you want focus breathing, any cheap Samyang Prime might do.
__________________
I wait for the day cost-efficient global shutter 60fps capable CMOS sensors emerge for use on major manufacturers' cameras. (Sony, Canon, etc.) Rolling Shutters are a plague.
Jack Zhang is offline   Reply With Quote
Old October 2nd, 2015, 01:39 PM   #5
Regular Crew
 
Join Date: Jul 2007
Location: Ft Myers, Florida
Posts: 65
Re: Bokeh-Focus-Object Shrinkage Effect?

Quote:
Originally Posted by Jim Andrada View Post
Maybe you're thinking of Focus Breathing?
Quote:
Originally Posted by Jack Zhang View Post
It does sound like lens breathing.
Yes that's it exactly. Len/Focus breathing. Couldn't remember for the life of me! Thanks.
Rob Johnson is offline   Reply With Quote
Old October 3rd, 2015, 11:46 PM   #6
Inner Circle
 
Join Date: Feb 2007
Location: Tucson AZ
Posts: 2,206
Re: Bokeh-Focus-Object Shrinkage Effect?

Glad we could fill in the mental blanks for you. I have more and more of them every year. Now just where did I leave my car keys???
Jim Andrada is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > The Tools of DV and HD Production > Open DV Discussion

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 07:24 PM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network