Hi,
from lens FAQ
<snip>
Q10. What are the closest and farthest points that will be in
acceptably sharp focus?
A. Sclose = h * So / (h + (So - f))
Sfar = h * So / (h - (So - f))
or, defining hr = h/(So - f)
Sclose = So * hr/(hr+1)
Sfar = So * hr/(hr-1)
Think of hr as the hyperfocal to subject distance ratio. These
formulas are also correct when hr is defined as hr = h/So and the N
used in computing h is actually Ne.
<snip>
I think the last paragraph is wrong. Can anyone comment?
bye,
Frank
-
This message is from the Pentax-Discuss Mail List. To unsubscribe,
go to http://www.pdml.net and follow the directions. Don't forget to
visit the Pentax Users' Gallery at http://pug.komkon.org .
