Possible errata in ASC Film manual re: super-8 DoF?
Posted 14 March 2006 - 06:42 PM
Posted 15 March 2006 - 10:09 PM
this may be of interest for you: DOF calculators
thanks, it was quite helpful -- The calculator ref.'ed above seems great. It assumes .025 mm as the CoC for 35mm which is about the same (within 2%) as ASC manual's .001 inches -- great. It then uses .0007 for 16mm (the ASC manual says either stick with .001 or go to .0005, this calc is in the middle -- good) and uses .0004 for 8mm (ASC manual says .002 -- five times larger and even larger than the value used for 35mm - NOT good! My original contention was that they meant .0002 but used .002 by mistake). As this calc. shows, the CoC generally gets smaller as the format gets smaller. Bottom line -- this calc gives very close results for 35mm with the ASC manual (called "all formats in ASC manual), but different results than are found in the ASC 8mm tables (example: 13mm lens at f/4 has a hyperfocal distance of over 13 feet [calc] or less than 2 feet? [ASC manual]).
Posted 16 March 2006 - 07:16 AM
This is really a question for David Mullen.
Personally I would trust the DOF tables in the Manual, they look logical to me. Though strangly in my book (9th) on a 13mm at f/4.0 the Hyperfocal Distance is 2' 9".
Posted 16 March 2006 - 07:59 AM
data for schneider/beaulieu 6-70.
Posted 16 March 2006 - 05:30 PM
Sorry Andy, after trying to be careful and precise with these numbers, I did accidentally slide a column over - it is 2' 9" in my 9th ed. also. Still a huge difference from the 13 feet of the calc.
More to the point (thanks S8 Booster for the schneider info).
From the schneider/beaulieu 6-70 tables above:
12mm f/1.4 hyperfocal = 34' 2"
(chart shows 1/2 hyperfocal which is where near focus starts)
at 10' distance: near = 6' 6"; far = 22' 1"
13mm f/1.4 hyperfocal = 7' 10"
(no common foc. lgth between ASC and schneider tables)
at 10' distance: near = 4'5"; far = inf.
the calc. S8 Booster ref. to:
12mm f/1.4 hyperfocal = 33' 8"
13mm f/1.4 hyperfocal = 39' 7"
Hoping to get a DoF "expert" to double check this before I figure out how to bring this to the attention of someone involved with the manual.
Posted 16 March 2006 - 05:49 PM