Your cameras has 15 mega-pixels? Bah! Mine has 570 mega-pixels.

By Grant Jacobs 18/01/2010 4

Some engineers at Fermilab are having fun!

Prototype 570 Mp camera. Source: Symmetry magazine.

They’re building a super-sized digital camera using CCDs (Charge Coupled Devices) that are particularly sensitive to near-infrared light to measure, among other things, redshifts of remote galaxies. The longer-term aim is to study the dark energy of universe more accurately than has been possible to date.

At a half metre in diameter, it’s a big digital camera!

(We really need an astronomer on these blogs. The technology of the endeavour impresses me and I understand it well enough to “get” it, but the astronomy itself is as new to me as it will be to most of my readers.)

It’s a long-running running project, with roots back at least as far as 2004 and a big, multi-lab, multi-national effort. The telescope is located in northern Chile, on Kitt’s Peak.

Source: CTIO newsletter
Kitt's Peak. Source: CTIO newsletter, Dec. 2009.

Looking at the photographs, if I ever make it to Chile, I’d love to visit this place. All those high-tech labs and buildings perched high up.

You can read the CTIO centre’s excellent newsletter free online (offered as PDF documents). As you might expect from an astronomy centre, they have great photos. For example, some of the backstory of the project can be found in the newsletter (PDF).

A great account of the science (with pictures) can be found in an article at Symmetry magazine by Kristine Crane (published by Fermi National Accelerator Laboratory and SLAC National Accelerator Laboratory). Subscription is free. Kristine’s article is well worth anyone reading. (It’s written for a general readership.)

While you might not make it to Chile, you can take the tours at Mt. John observatory at Lake Tekapo in the heart of the South Island of New Zealand (photo below).

Source: wikipedia
Mt John Observatory, New Zealand. Source: wikipedia

New Zealand has been short-listed as one possible location for the Square kilometre array (Ska) telescope, which is–in a manner of speaking–an even bigger camera. Here’s hoping it comes our way!

4 Responses to “Your cameras has 15 mega-pixels? Bah! Mine has 570 mega-pixels.”

  • As an aside, none of my cameras have 15MP. Albeit a wet scan of a film-negative or slide, in a drum scanner, can produce a mighty-big image. :) Pro cameras like the Nikon D3 are still 12 MP. In photography, size isn’t everything and there’s actually some big costs to squeezing more (and tinier) pixel-sensors on to a CCD/CMOS sensor.

    The real photographic trick here is the sheer size of the sensor (half a metre across) combined with the cooling (-10 degrees) to reduce digital noise. The size means that each of the CCD sensors (there are 74 of these silicon wafers) is a mere 7 MP. Bearing in mind, that each of these CCD’s has an area of 18 cm2. In a FF digital SLR, the sensor is about 8.4cm2 and an APS-C DSLR, the sensor is about 4.2 cm2.

    What that means- in practical terms- is that the pixel sensors on these CCD’s are much, much larger than on a digital camera, and they are also better spaced. This is going to have a very big effect on the amount of detail the Fermilab camera will record. Most importantly, the image will be extremely free of any digital noise (colour artifacts), which I expect is the whole point.

  • I agree that there’s more to it that a pixel count. (I’ve seen an advert for a 14.7 MP camera; I forget the details now, maybe it was a typo for 12.7?!)

    I read the overall size of the Fermilab camera as quoted at 500 MP, but the details were eluding me. Thanks for filling in.

    I’d love to have time to get properly into the technical side, as I’d love to try digital photography (I did a lot of photography as as a kid), but seeing as I can’t afford a decent digital camera I haven’t been very motivated too!

  • I like digital cameras in many ways. I think the point-and-shoot compacts cameras have really transformed the way people can take photographs. It’s made family snapshots easy and straight forward.

    A DSLR also makes photography a lot more accessible to people. But in terms of basic physics, it’s still about the ability of a lens to transmit light onto a sensor. There are some hard constraints technology can’t fix. You can’t beat high-quality, large aperture lenses with software.

    I think though, a lot of people do get confused about the effect of mega-pixel size on image quality. The problem comes down to the physics. SLR cameras have bigger sensors than point-and-shoot cameras. Often the decision is to put larger pixels on, rather than more smaller ones. The pixels on an SLR end up being larger many more microns across. This is to improve the image quality. Things like the dynamic range, colour accuracy, level of noise, all matter for a quality print.

    Sensor size matters for both the ability to capture colours and reduce digital noise (random colour artifacts). In a point and shoot camera, this means that the performance above ISO400 typically sucks badly. The extra detail promised by a high MP count also suffers, as the high levels of noise are countered by a strong anti-aliasing (AA) filter. This reduces both noise and ha, ha, the detail.

    There are some point-and-shoot cameras now operating with tiny sensors and 12-14 MP. Pretty scary. APS-C format DSLR’s are now often between 12-15 MP. And there are some FF DSLR cameras with 25 MP (Sony alpha 900) – think very, very big prints- fine art, studio type stuff. Alebit, for low light, noise-free performance the Nikon D3/D700 with their 12MP FF sensors are pretty much the top of the game at the moment.

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