Re: [OM] IMG: Sunrise, Moonset

[Ken Norton]

> Nothing like a little math to obfuscate things. I never did get the
> hyperfocal thing. We were lead to believe that everything between the marks
> was "in focus". In or out. Kinda digital. But when you turn the focusing
> ring what you see is definitely analogue. What is magical about those little
> marks? Well maybe it was the limitations of the media and equipment of the
> day. I think that "hyperfocal" is a carryover from the past that may not
> have much relevance with today's technology. The hyperfocal spread is
> shrinking as the technology improves to the point where it becomes
> meaningless. Maybe that's why the markings disappeared.

DoF is an output-based calculation. It has to do with the reasonable
appearance of sharpness to the normal human eye (as opposed to the
Moose Eye), in an 8x10 print at normal viewing distances. Personally,
I find that adding one stop to the hyperfocal markings is a little
better for me as song as I'm not punching up too hard into diffraction
blurring.

As to the disappearance of the markings, I'm a whole lot more cynical.
The markings disappeared with second-generation autofocus systems that
no longer focus the lens through a helicoid and extension, but through
the changing of the effective focal length of the lens (internal lens
movement).  Without a big rotating barrel and a very minimal movement
in the focus mechanism itself, the ability to adequately display DoF
markings in any usable way has been eliminated. Fuji has done a good
job, though of bringing back some of this within the viewfinder with
distance-scale focusing.

AG
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