SpitfireIX
Philosopher
If I may indulge in the slightest moment of woo, in my life I've seen a pile of snapshots in my time and the best of the Moon photos are remarkably clear and good for being the products of amateurs.
There. That's out of my system, since a Hasselblad shooting 120 film leaves a lot of sparepixelsgrains of silver that can be sacrificed to the cropping process. And the most striking thing about them is how CLEAR they are. We think of air as being invisible, but on Earth it and what it contains are always there, reflecting and refracting light.
http://www.clavius.org/photoqual.html
JayUtah said:As a matter of fact, a significant percentage of the lunar surface photographs are blurred, unfocused, incorrectly exposed, or otherwise flawed. These photos weren't generally known to the public until recently because they weren't interesting to editors and publishers of popular works and therefore not cost-effective to duplicate. But now that it's possible to efficiently digitize the many thousands of photographs taken on the moon (even the bad ones) and distribute them cheaply via the Internet, we can see the full gamut of lunar surface photography. . . .
The Apollo astronauts were trained in "zone focusing", a technique used by photojournalists and sports photographers who often don't have the time to focus visually or by measurement. At a high f-stop, a camera's depth of field increases. This means that when the lens is set to focus at a certain distance, objects somewhat nearer and farther from this ideal distance are also sharply focused. The narrower the aperture (i.e., the higher the f-stop), the greater the depth of field. And the sloppier the photographer can be be about his focus setting. The Zeiss Biogon lens used by the astronauts had an indicator that specified the near and far boundaries of the depth of field for each combination of focus and f-stop.
Zone focusing is a technique whereby the f-stop is kept high, resulting in lenient depths of field. The focus range is then divided into "zones" corresponding approximately to near, medium, and far. These zones of clear focus overlap slightly and correspond to preset positions of the focus ring. The Zeiss Biogon lens provided to the astronauts had "detents" or click-stops that corresponded to these three zones. The astronaut had simply to push the tab on the focus ring to one of three easy-to-find stops to select the focus zone depending on the rough distance to the subject.
