High Dynamic Range

Exposure values or EVs are numbers that refer to combinations of lens aperture and shutter speed. Your eye is capable of discerning 12EV but a typical camera can only handle about 6.


So if you shoot the same image at a range of speeds and sandwich them together you can see a higher dynamic range, one closer to what you're used to seeing with your eye. Photoshop has a handy tool that will help combine multiple images, and there are several stand-alone programs to help too.

Here's a shot properly exposed for the tree trunk (click any image to enlarge):

There's 4.0EV difference between the black, dark tree trunk and the bright, white surf and clouds behind. Here's the shot combined with a properly exposed beach (Kauai HI).

There are a few artifacts that give away the fact that more than one images is involved: note the branches at the top that were moving in the tradewinds. If there are moving people or cars in one of the shots they'll look ghostly.

This picture, taken just after sunrise, is made up of 4 images with a range of 6.5 EV. When the sky was properly exposed the mountain was just a black silhouette. Properly exposed for the mountain, the sky was completely blown out, totally white.

Here's a better example I made a while back in a dark hangar.

But take a look at these and these!

Was St. Augustine psychic?

St. Augustin, you may recall, was the first archbishop of Canterbury, and was considered the Apostle to the English and a founder of the English Church. [Yike! No he wasn't, as a sharp eyed reader noted in the comment below. Mea Culpa, wrong Saint Augustine. The right one was 200 years earlier (November 13, 354 – August 28, 430) and was one of the most important figures in the development of Western Christianity, and considered to be one of the church fathers. He framed the concepts of 'original sin' and 'just war'.]

About 1400 [make that 1600] years ago he wrote:

"Usually, even a non-Christian knows something about the earth, the heavens, and the other elements of this world, about the motion and orbit of the stars and even their size and relative positions, about the predictable eclipses of the sun and moon, the cycles of the years and the seasons, about the kinds of animals, shrubs, stones, and so forth, and this knowledge he holds to as being certain from reason and experience. Now, it is a disgraceful and dangerous thing for an infidel to hear a Christian, presumably giving the meaning of Holy Scripture, talking nonsense on these topics; and we should take all means to prevent such an embarrassing situation, in which people show up vast ignorance in a Christian and laugh it to scorn. The shame is not so much that an ignorant individual is derided, but that people outside the household of faith think our sacred writers held such opinions, and, to the great loss of those for whose salvation we toil, the writers of our Scripture are criticized and rejected as unlearned men. If they find a Christian mistaken in a field which they themselves know well and hear him maintaining his foolish opinions about our books, how are they going to believe those books in matters concerning the resurrection of the dead, the hope of eternal life, and the kingdom of heaven, when they think their pages are full of falsehoods and on facts which they themselves have learnt from experience and the light of reason? Reckless and incompetent expounders of Holy Scripture bring untold trouble and sorrow on their wiser brethren when they are caught in one of their mischievous false opinions and are taken to task by those who are not bound by the authority of our sacred books. For then, to defend their utterly foolish and obviously untrue statements, they will try to call upon Holy Scripture for proof and even recite from memory many passages which they think support their position, although they understand neither what they say nor the things about which they make assertion."
-- The Literal Meaning of Genesis, translated by John Hammond Taylor
So was he psychic? No, of course not, no one is. But it looks like this kinda thing has gone on before. Young Earth Creationists, the Intelligent Design bunch, those that don't think evolution is a fact, and others literalists who claim the Bible proves the nonsense they spout could take a hint from one of their own, seems to me.

Can Moonbeams Heal?

Oh puh-leeze.

Must be a slow news day. CNN is touting, front page, an old story from a local TV station in Tuscon that breathlessly reported there's an outfit in Arizona selling moonlight as a cure all.

The piece starts, "Conventional wisdom says that whenever there's a full moon, strange things happen." Right off the bat you know this is gonna be a crock. Or at least you know that if you understand that 'conventional wisdom' is generally wrong—and definitely wrong in this case.

Conventional wisdom had it that the Sun rotates around the earth, remember. Come to think of it 20% of the people in the U.S. still do. Conventional wisdom, for that matter, used to be that Thor made thunder, although that might more rightly be called religious 'wisdom.'

Why can't people get it through their heads that you can't believe everything that comes into it. "Don't believe everything you think," as the bumper snicker says.

The CNN report goes on sagely, "Whether it's hocus pocus or science, moonbeam healing has its believers." Well, duh. And some people believe in fairies and angels. Since when is that news?

Seems these idiots down in Arizona have set up a 50 foot reflector to collect moonlight. One Eric Carr was willing to go on record after spending a few minutes basking in a moonbeam. Doesn't need asthma medicine anymore, he saud. Changed his life.

Yup sure did. Used to just be a closet nut case, now everyone knows.

Figure anyone thought about the fact that moonlight is just reflected sunlight? Or that in this case it is reflected reflected sunlight?

Why not tout the healing power of mirrors?