20130716

Non-interchangable SLR?

I ran across this article about a new, lensless camera earlier today, and am a bit confused about its terminology.

To start with, I think what they're starting with is a pinhole camera controlled by an LCD screen. That is to say, they open a hole in the LCD lattice to be the pinhole. That would explain what they mention about infinite depth of field (a characteristic of pinhole cameras).

And I think there's something there about opening multiple pinholes at once to get a better image (an interesting idea, for sure).

But where complete confusion sets in, for me, is when they start talking about single pixels as the sensing element behind the LCD array. They must be using a weird definition of a pixel, because one pixel using the normal definition gives almost no information. Try reducing down any picture to height and width of 1 to see what I mean. I won't say there's no information there, but it's a damned small amount.

So I think what they're actually talking about is a single DSLR-like sensor, and possibly doubling that to two sensors. That would make some sense.

Other than that, I think it's a pinhole camera with an array of "pinholes". One limitation, if that's so, is that you'll be limited in exposure length, I believe, because two opposing polarizing elements don't stop all light. Don't believe me (and it's certainly counter to what I heard in physics class in high school)? Well, variable neutral density filters work by taking two one-stop polarizing elements, and rotating one of them. All of them go from two stops to eight (which is a nice range), but even at eight stops, you can still take usable pictures (heck, I've got a ten-stop filter that still allows usable pictures).

Anyway, it's an interesting idea, and I'm curious to see what they do with it.  Thinking about it, something like this would probably be perfect for a cell phone camera, where space is very constrained.  Hmm...

It also just occurred to me... Maybe what they were referring to, in using the word pixel, was a specific spot (any specific spot) on the LCD "screen"ing the sensor.  If so, the article was not well phrased.  It's also a bad term to use, because pixel is short for "picture element", and the screen blocking the sensor does not have any picture elements in it.

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