Ordinarily, both Depth of Field calculations and Hyperfocal Distance calculations are based upon the FALSE assumption that they human eye is FOOLED into seeing a certain diameter Blur Circle (vs. a perfectly focused 'Point') and thinking 'In focus'...what is commonly referred to a 'Manufacturer Standard' CoC assumption. Our optical practitioners actually strive to correct our vision to even better standards than 'manufacturer standard', So when we look at a print we actually see 'blurry' rather than 'in focus' (as the charts and DOF scale marks on lenses would fool us into thinking.) That is a key reason that so many photographers decades ago would use the DOF scale marks on lens that was 1-2 EV larger aperture than shooting aperture...if f/16 was shooting aperture, they consulted the DOF scale marks on the lens for f/8.
IOW the standard CoC diameter assumption is too large, in the computation of most calculators and tables and DOF scale marks on lenses! A standard DOFcalculator says 100mm f/8 lens focused at 10m has DOF zone of 5.4m, but what our optician corrects our eyes to has DOF zone of only 1.7m !
And if your calculations for DOF or Hyperfocal Distances are applied to an even bigger print (than 8" x 10") the calculations are INVALIDATED because the Blur Circles are magnified in the enlargement process and the eye CAN more easily see 'blur' rather than 'point' even more dramatically!
One problem in using Hyperfocal Distance calculators is that modern AF lenses (even the ones first available in the 90's for film cameras) have such spatially compressed distance marking that if you needed to set 18' on the distance, where in the gap between 10' and Infinity does one FIND 18' vs. any other distance?! For the 100mm f/8 lens, the Hyperfocal Distance is at 117m...just WHERE is that found on the distance scale, even a manually focused fixed FL lens?!
IOW the standard CoC diameter assumption is too large, in the computation of most calculators and tables and DOF scale marks on lenses! A standard DOFcalculator says 100mm f/8 lens focused at 10m has DOF zone of 5.4m, but what our optician corrects our eyes to has DOF zone of only 1.7m !
And if your calculations for DOF or Hyperfocal Distances are applied to an even bigger print (than 8" x 10") the calculations are INVALIDATED because the Blur Circles are magnified in the enlargement process and the eye CAN more easily see 'blur' rather than 'point' even more dramatically!
One problem in using Hyperfocal Distance calculators is that modern AF lenses (even the ones first available in the 90's for film cameras) have such spatially compressed distance marking that if you needed to set 18' on the distance, where in the gap between 10' and Infinity does one FIND 18' vs. any other distance?! For the 100mm f/8 lens, the Hyperfocal Distance is at 117m...just WHERE is that found on the distance scale, even a manually focused fixed FL lens?!
Last edited: