T3D using anafa and DOF together

[john bercovitz <bercov@xxxxxxxxxxx>]

The first thing is to go to 
http://www.angelfire.com/ca2/tech3d/techdocs.html
and get
MAOFD Spreadsheet - short (Excel file). 
and 
Spreadsheet for DOF (Excel file). 

Next, get both of them up on your screen.

Start with anafa
Input your lens' focal length, the desired maximum
on-film deviation, the desired stereobase (I like 67
but you might like something else).  Then put in a 
range choices for the distance you will focus on.

I put in 50 mm, 1.67 mm, 67 mm, and then a span of 
distances from 200 to 800 mm (8 to 32").  How deep is 
my scene?  Let's say it is 70 mm.  Then I would choose 
the 400 mm focus distance and set out my objects over 
the distance from an to af.  In other words, I would 
put my closest object at 368 mm and my farthest at 
438 mm as shown on the spreadsheet.  In addition, I 
would set up a temporary monument at 400 mm to focus on.

Next I would go to DOF and input my criterion for
acceptable CofC which is 2000 for this scene since I'll 
say it has fairly sharp-edged & contrasty objects in it.
Then I would enter my lens' focal length, again 50 mm, 
and then a string of f/numbers to check.  Going over to
the next colum which has "enter" at the top, column F,
I would enter the 400 mm from anafa down that whole column.

>From anafa, we know the coverage to be from 368 to
438 mm.  What f/number do I have to stop down to?  It
looks like the second row has the answer:  f/22 will
span from 367.6 to 438.6 mm distance.

John B

PS to MG: How about that little coincidence?  8-)


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