Tuesday, 13 November 2012

Chromatic Aberration a Go-Go

Yikes!  It seems my camera has been experimenting with e-peyote.  I had an inkling this image would turn out a little strange, but this is way stranger than I had thought.

Basically, I took the Itorex Pan-Focus lens out for a lunchtime walk last week, bolted onto the front of my Panasonic GF1.  It was a sunny day, and I pointed the assembly directly towards, but not at, the sun.  Those leaves belong to one of the weirdest plants on the planet (including totally bonkers things like Rafflesia): Gunnera manicata a.k.a. the Giant Brazilian Rhubarb.  Each leaf is about about four feet across, and the whole plant, including the underside of the leaf ribs, is covered with wicked spines.  Seriously strange: the first time you see one, you suspect that someone may have slipped something hallucinogenic into your drink.  They are distinctly alien-looking, especially when heavy rain has exposed their ugly, knobbly rhizomes.

But the weirdest thing is the optical distortion.  Now that's what I call chromatic aberration! I'm used to seeing a rainbow effect in the LCD viewer of a digital camera when it is pointed towards the sun, but it rarely actually appears in the final image.  Here, it looks so much like the result of some tacky filter that I'd be embarrassed ever to use the image for any serious purpose.  Wot, no starburst?

Strangest of all, though, are the "doughnut" rings scattered over the whole frame.  It must be some kind of internal reflection off the cheap glass element that sits in front of the fixed f/40 pinhole, or maybe it's a virtual image of the pinhole itself.  I have no idea -- I'm a photographer, not a physicist, I'm afraid.

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