Archived posting to the Leica Users Group, 2005/08/30

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Subject: [Leica] Hyperfocal Focusing
From: mark at (Mark Rabiner)
Date: Tue Aug 30 18:20:16 2005

Yes as Marc James Small says you have to define "sharpness" as it's
relative. His relatives are Welsh, so are mine.
People who don't know about this dept of field thing think the only thing
that's in focus is what you've focused at. That one distance. If they have
an astronomy background it can be hard to convince them otherwise. In a
sense they're part right. They've been ignoring all those funny little f
stop numbers all over the lens they figure its like stuff on a VCR you just
ignore 90 percent of it. The pictures still come out or you still get to see
your movie.
They're f stops you've supposedly set already... And that they're laid out

If I'm shooting at f11 I crank the infinity mark over to the 11 at the
right. On the f11 DOF mark at the left I see 10 feet.
Now those marks are based as Marc James Small says on circle of confusion
agreed upon calculations based on the Circle of Confusion Conference (CCC)
held in 1879 in the center of the earth where the magnetic field would be
the most neutral and not throw off their calculations.
These supposed a 8.5 x 6.5 inches (21.6cm x 16.5cm), a size which became
known as whole-plate. Not dinner plate but window pane plate. If the
pictures were round who knows? We'd be shooting Demitasse film.
I want things to look "in focus" or "sharp" (sorry Erwin!) when I print a
13x19 inkjet or 16x20 darkroom print as those are far from uncommon for me
and don't even represent the highest end of things which I think if you
planned for you'd never get your stuff out the door without big wheels and a
hired hand. So if I need an area between 10 feet to infinity sharp (with a
50 in 35mm format) I'll stop it down another stop to f16 for some leeway. At
Brooks they tell you to give it two stops not just one someone on the LUG
said 11 years ago. 
IN commercial photography its not unusual that you need to for sure get
something in focus from say 8 feet to 20;  a definite area. The whole area
for sure as there's stuff in there that the people who are paying you are
selling. So you've got to get into with your DOF issues. And you plan for 5
to 30 in case they decide to plaster the side wall of Times square with it.

But street shooting is the opposite and especially with a rangefinder camera
which you don't want to be always focusing all the time  with as its harder
to do. You want to be shooting fast. From the "hip" even. Daddy Oh.
You need that zone in front of you that you know is sharp. And it tends to
be better and even easier if it just extends all the way out to infinity.
The metaphysical implications are numerous.
So you end up doing Hyperfocal stuff if you realize it or not.
Just remember to breath hard in that paper bag. Helps with focusing.
Always breath.

Mark Rabiner
Portland Oregon

In reply to: Message from msmall at (Marc James Small) ([Leica] Hyperfocal Focusing)