Go Back   Steve's Digicams Forums > Digital SLR and Interchangeable Lens Cameras > Canon EOS dSLR

Reply
 
Thread Tools Search this Thread
Old Apr 20, 2010, 2:20 PM   #1
Member
 
Join Date: Apr 2010
Location: Plymouth, UK (the original one!)
Posts: 59
Default I can't get the hang of this Depth of Field lark!

Been involved with photography for more than 30 years and I just can't seem to get the hang of this depth of field lark!

What can I say? It's beyond me!

I thought that the more you opened up the aperture the less Depth of Field you got, but I took three different images all at the same exposure settings (1/10 sec @ f3.5, exif intact) all with the same lens from the same distance and the Depth of Field is different in all of them :help:

Focus was on the third Uniross battery from the right.







Beats me!

Ed Bray is offline   Reply With Quote
Sponsored Links
Old Apr 23, 2010, 12:58 PM   #2
Member
 
Join Date: Apr 2010
Location: Plymouth, UK (the original one!)
Posts: 59
Default

No comments?
Ed Bray is offline   Reply With Quote
Old Apr 23, 2010, 1:12 PM   #3
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

I saw it when you first posted it and looked at the EXIF info, trying to figure out if you modified it (since EXIF editors are easily available), and if your post was accurate in saying they were all taken "at the same exposure settings (1/10 sec @ f3.5, exif intact) all with the same lens from the same distance"; or if you you edited some of them before downsizing to post them (for example, shooting from a far enough distance to get good depth of field and using gaussian blur to simulate a shallower depth of field on the first two but not the last one).

I didn't spend a lot of time on it, and I figured you'd let us in on what you did eventually.
JimC is offline   Reply With Quote
Old Apr 23, 2010, 1:40 PM   #4
Member
 
Join Date: Apr 2010
Location: Plymouth, UK (the original one!)
Posts: 59
Default

As stated, all three images were taken at the same distance with the same exposure settings with the same lens. The exif data has not been manipulated in any way!

There is very little processing apart from resizing and some USM, no blur was used, all the differences in depth of field were as taken in camera!

There is also nothing wrong with the lens such as sticking aperture blades either!

I was hoping some members would try to attampt to solve the riddle?
Ed Bray is offline   Reply With Quote
Old Apr 23, 2010, 1:43 PM   #5
Senior Member
 
TCav's Avatar
 
Join Date: Sep 2005
Location: Washington, DC, Metro Area, Maryland
Posts: 13,572
Default

That Canon TS-E 24mm f/3.5L II is a very nice lens.
__________________
  • The lens is the thing.
  • 'Full Frame' is the new 'Medium Format'.
  • "One good test is worth a thousand expert opinions." - Tex Johnston, Boeing 707 test pilot.
TCav is offline   Reply With Quote
Old Apr 23, 2010, 1:45 PM   #6
Senior Member
 
billy's Avatar
 
Join Date: May 2004
Location: Ohio USA
Posts: 1,733
Default

Not sure on this, but I can tell you that the third photo was not taken at the same angle as the rest.
billy is offline   Reply With Quote
Old Apr 23, 2010, 1:54 PM   #7
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

Quote:
Originally Posted by Ed Bray View Post
As stated, all three images were taken at the same distance with the same exposure settings with the same lens. The exif data has not been manipulated in any way!
[snip]

I was hoping some members would try to attampt to solve the riddle?
If that's the case, then it's probably only a riddle to us and not to you, hence my comment that you'd probably let us know what you did eventually. ;-)

IOW, some technique (other than normal Depth of Field calculations) would apply to those images (use of specialized lenses like a Lens Baby with Soft Focus additions, other lenses with that ability, etc.).

With a standard lens, you're not going to have that much variation unless the aperture was stopped down more than indicated in the EXIF (or not stopped down as much as indicated in the EXIF) unless editing was performed.

What was the focus distance from the battery you were focusing on?
JimC is offline   Reply With Quote
Old Apr 23, 2010, 2:08 PM   #8
Member
 
Join Date: Apr 2010
Location: Plymouth, UK (the original one!)
Posts: 59
Default

Quote:
Originally Posted by JimC View Post
If that's the case, then it's probably only a riddle to us and not to you, hence my comment that you'd probably let us know what you did eventually. ;-)

IOW, some technique (other than normal Depth of Field calculations) would apply to those images (use of specialized lenses like a Lens Baby with Soft Focus additions, other lenses with that ability, etc.).

With a standard lens, you're not going to have that much variation unless the aperture was stopped down more than indicated in the EXIF (or not stopped down as much as indicated in the EXIF) unless editing was performed.

What was the focus distance from the battery you were focusing on?
About 8"

Nothing was added to the lens (ie lens baby or filters). But you are close with your theory!
Ed Bray is offline   Reply With Quote
Old Apr 23, 2010, 2:11 PM   #9
Member
 
Join Date: Apr 2010
Location: Plymouth, UK (the original one!)
Posts: 59
Default

Quote:
Originally Posted by TCav View Post
That Canon TS-E 24mm f/3.5L II is a very nice lens.
Bang on, three exposures all the same, one taken with no swing, one taken with full left swing and one with full right swing.

The batteries were arranged to allow full right swing to take the plane of focus along the line of batteries!
Ed Bray is offline   Reply With Quote
Old Apr 23, 2010, 2:12 PM   #10
Senior Member
 
TCav's Avatar
 
Join Date: Sep 2005
Location: Washington, DC, Metro Area, Maryland
Posts: 13,572
Default

Very nicely done.
__________________
  • The lens is the thing.
  • 'Full Frame' is the new 'Medium Format'.
  • "One good test is worth a thousand expert opinions." - Tex Johnston, Boeing 707 test pilot.
TCav is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 9:08 PM.