Olympus-OM
[Top] [All Lists]

[OM] Focus stacking - I have met the enemy...

Subject: [OM] Focus stacking - I have met the enemy...
From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx>
Date: Fri, 02 May 2008 11:17:56 -0400
I have met the enemy and he is me.  After going back to analyze the 
individual frames and reviewing them by rapidly stepping through like a 
movie, I suddenly realized that the last frame didn't fit the sequence. 
  Only then did I recall that (for reasons I can't recall) I re-shot the 
last frame as a near duplicate of the first.

CZM is critically dependent on frames being ordered in the proper 
sequence of focus distance and makes that assumption.  I apparently 
passed it a real "gotcha" by giving it six frames in proper order but a 
seventh that suddenly jumps back to a near replica of frame 1.  When I 
remove the seventh frame and rerun the app using the very simple and 
fully automated "do stack" macro all is well.  Well, all except the few 
wilting blossoms which cause a few artifacts.  But I think these can be 
easily cloned out and the resulting image is eminently usable.  The CZM 
manual also speaks of artifacts near the edges of the frame and I 
noticed that there is a strange mirroring of the branch where it nears 
the right hand edge of the frame.  But this is also easily cropped.

Here's what it looks like.  The first frame is the full image with 
comments on the motion artifacts and mirroring.  The second frame is a 
50% pixel crop showing the area with the motion artifacts.  Even though 
it's only a 50% pixel crop, on screen, it's probably about twice life size.
<http://www.chucknorcutt.com/focus_stack/index.htm>

Chuck Norcutt

==============================================
List usage info:     http://www.zuikoholic.com
List nannies:        olympusadmin@xxxxxxxxxx
==============================================

<Prev in Thread] Current Thread [Next in Thread>
Sponsored by Tako
Impressum | Datenschutz