BobA wrote:
In article ,
Alan Browne wrote:
On 2013.06.24 10:03 , BobA wrote:
In article ,
peternew wrote:
[ ... ]
No. It's not a fixed distance. It's a range in whch there is apparent
focus.

http://en.wikipedia.org/wiki/Hyperfocal_distance

The first line of this article:

In optics and photography, hyperfocal distance is a *distance* beyond
which all objects can be brought into an "acceptable" focus

Read it all
QUOTE
Definition 1: The hyperfocal distance is the closest distance at which a
lens can be focused while keeping objects at infinity acceptably sharp.

When the lens is focused at this distance, all objects at distances from
half of the hyperfocal distance out to infinity will be acceptably sharp.
ENDQUOTE

So while objects from h to infinity are "acceptably" in focus so are
objects from h/2 to h (and of course out to infinity.

Seriously?

Reading the rest of the article doesn't change that the
hyperfocal distance is a distance. Of course it's not
just any distance. The distance must meet criteria.

You have to set the lens to a distance, h -- not a range.
The range h to infinity is the acceptable focus criteria.
The range h/2 to infinity is the acceptable focus property.

Either that, or I need to go back to early grammer school.

It's hard to determine from what they say if it is the
words or the concept of a hyperfocal distance, but
clearly Alan and Peter do not understand one or the
other; and whichever it is, neither Alan nor Peter are
making any sense at all!

For the benefit of both Alan and Peter:

1) "Hyperfocal distance" is a *single* distance, not a range.
2) "Hyperfocal distance" is not an area.
3) "Infinity/3" is still Infinity.

But as to Peter's curious method of determining hyperfocal distance:

"Look at the closest distance for which you get an in
focus image for infinity. Then look and se where you
are in focus at about 1/3 of that distance at
f/16. The area between that point and infinity will be
your hyperfocal distance.

The first step provides focus at the hyperfocal
distance, so what need is there for the rest of that
nonsense! Not to mention that those steps absolutely do
not provide any clue about the hyperfocal distance.
(I'm still wondering how that reference to f/16 has
significance!)

Here is a very simple chart showing the camera
location at C, the Focus distance at F, the nearest
point considered in focus at NF, and the far edge
of the Depth of Field at Inf.

The hyperfocal distance when those conditions are
met is the distance from C to F. When all else is
constant, the distance from C to F is greater for
larger apertures.

C NF F Inf
| | | |
|-----|---------|-----------/~~~/--|

| |-----------------------/~~~/--|
Depth of Field

|-----------------|
Hyperfocal Distance


Obviously Hyperfocal distance is a fixed distance, not a
range and cannot be considered an area.

--
Floyd L. Davidson http://www.apaflo.com/
Ukpeagvik (Barrow, Alaska)