> On Apr 11, 2015, at 9:59 AM, Stanley Halpin <[email protected]> > wrote: > > Assuming you were using 200mm at 20’, f/11 the depth of field would be 4”. > 50mm at 20’, f/11 would be 5’9” > > The one app I am using to calculate these numbers doesn’t want to use an > aperture smaller than f/11. > The other app says 2’11” for 200mm, f/22 at 20’ but I am not sure I quite > trust that.
I checked out depth of field apps in the Apple App Store. I found several, but didn’t find Peter’s f/Calc. Ended up purchasing Simple DoF. Using it I get different results from those you report above: For 200mm, f/ll, at 20’ I get DOF of 1’4” versus you 4”. For 50mm, f/11, at 20’ i get DOF of 31’3” versus your 5’9”. For 200mm, f/22, at 20’ we are closer. I get 2’8” versus your 2’11" I trust you more than the app at this point. But why the—for the most part—wild discrepancies? ------------------------------------------------------------------------------------------ Eric Weir Decatur, GA USA [email protected] "Our world is a human world." - Hilary Putnam -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
