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World’s largest camera: 3.1 gigapixels for epic timelapse panos of the universe

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World’s largest camera: 3.1 gigapixels for epic timelapse panos of the universe


We have a winner for sensor Top Trumps: the LSST camera is the world’s largest astronomy camera. It’s more than 350 times the size of a full-frame sensor, for reference.

Photo: Jacqueline Ramseyer Orrell/SLAC National Accelerator Laboratory

“Space,” according to Douglas Adams’ Hitchiker’s Guide to the Galaxy. “is big. Really Big. You just won’t believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it’s a long way down the road to the chemist’s, but that’s just peanuts to space.”

It turns out the same is true of cameras made to map space. You may think your full-frame camera is big but that’s nothing compared to the Legacy Survey of Space and Time (LSST) camera recently completed by the US Department of Energy’s SLAC National Accelerator Laboratory.

You may have seen it referred to as the size of a small car, but if anything that under-sells it. SLAC has essentially taken all the numbers you might recognize from photography, made each of them much, much bigger and then committed to a stitched time-lapse that it hopes will help to understand dark matter and dark energy.

Unlike many astro and space projects, LSST is recognizably a camera: it has a mechanical shutter, lenses and rear-mounting slot-in filters.

Image: Chris Smith / SLAC National Accelerator Laboratory

We got some more details from Andy Rasmussen, SLAC staff physicist and LSST Camera Integration and Testing Scientist.

The LSST has a 3100 megapixel imaging surface. That surface is an array made up of 189 individual sensors, each of which is a 41 x 40mm 16.4MP CCD. Each of these sensors is larger than consumer-level medium format and when arranged together gives an imaging circle of 634mm (24.9″). That’s a crop factor of 0.068x for those playing along at home.

The individual pixels are 10μm in size, making each one nearly three times the area of the pixels in a 24MP full-frame sensor or seven times the size of those in a 26MP APS-C, 61MP full-frame or 100MP 44 x 33 medium format model.

To utilize this vast sensor, the LSST has a lens with three elements, one of which is recognized by Guinness World Records as “the world’s largest high-performance optical lens ever fabricated.” The front element is 1.57m in diameter (5.1 ft), with the other two a mere 1.2m (3.9 ft) and 72cm (2.4 ft) across. Behind this assembly can be slotted one of six 76cm (2.5 ft) filters that allow the camera to only capture specific wavelengths of light.

One of the six 76cm (2.5 ft) filters that are swapped over, typically once the camera has shot a set of images of the 1000 regions of the sky it captures.

Photo: Jacqueline Ramseyer Orrell/SLAC National Accelerator Laboratory

This camera is then mounted as part of a telescope with a 10m effective focal length, giving a 3.5 degree diagonal angle of view (around a 634mm equiv lens, in full-frame terms). Rasumussen puts this in context: “the outer diameter of the primary mirror is 8.4 meters. Divide the two, and this is why the system operates at f/1.2.”

That’s f/0.08 equivalent (or around eight stops more light if you can’t remember the multiples of the square root of two for numbers that small).

Each 16MP chip has sixteen readout channels leading to separate amplifiers, each of which is read-out at 500k px/sec, meaning that it takes two seconds. All 3216 channels are read-out simultaneously. The chips will be maintained at a temperature of -100°C (-148°F) to keep dark current down: Rasmussen quotes a figure of < 0.01 electrons / pixel / second.

But the camera won’t just be used to capture phenomenally high-resolution images. Instead it’ll be put to work shooting a timelapse series of stitched panos.

The sensor array under construction in 2020. Each of the sensors in the 3 x 3 array being installed is a 41 x 40mm chip. The final camera uses 189 of these imaging sensors, plus another 8 for positioning the camera, along with 8 wavefront sensors at the corners of the array.

Photo: Farrin Abbott/SLAC National Accelerator Laboratory

The camera, which will be installed at the Vera C. Rubin Observatory in Chile, will shoot a series of 30 second exposures (or pairs of 15 second exposures, depending on the noise consequences for the different wavelength bands) of around 1000 sections of the Southern sky. Each region will be photographed six times, typically using the same filter for all 1000 regions before switching to the next, over the course of about seven days.

This whole process will then be repeated around 1000 times over a ten-year period to create a timelapse that should allow scientists to better understand the expansion of the universe, as well as allowing the observation of events such as supernova explosions that occur during that time.

The sensors, created by Teledyne e2v, are sensitive to a very broad range of light “starting around 320nm where the atmosphere begins to be transparent,” says Rasmussen: “all the way in the near-infrared where silicon becomes transparent (1050nm),”

The sensors, developed in around 2014, are 100μm thick: a trade-off between enhanced sensitivity to red light and the charge spread that occurs as you use deeper and deeper pixels.

No battery life figures were given, but the cost is reported as being around $168M.



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Pentax K-1 and K-1 II firmware updates include astrophotography features (depending on where you live)

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Pentax K-1 and K-1 II firmware updates include astrophotography features (depending on where you live)


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Yesterday, Ricoh quietly released firmware 2.50 for its Pentax K-1 and K-1 II DSLRs. However, the features you can expect to gain from this update may depend on your geography.

Ricoh’s English-language firmware pages for the K-1 and K-1 II state that firmware 2.50 delivers “Improved stability for general performance.”

However, astute Pentax users noted that Ricoh’s Japanese-language firmware pages (translation) indicate that the update also includes a limited feature called “Astronomical Photo Assist,” a collection of three new features designed for astrophotography: Star AF, remote control focus fine adjustment, and astronomical image processing.

Star AF is intended to automate focusing on stars when using autofocus lenses. Rather than manually focusing on a bright star and changing your composition, it promises to let you compose your shot and let the camera focus.

Remote control fine adjustment allows users to adjust focus without touching the lens and requires Pentax’s optional O-RC1 remote. Astronomical image processing will enable users to make in-camera adjustments to astrophotography images, including shading correction, fogging correction, background darkness, star brightness, celestial clarity, and fringe correction.

Astronomical image processing on the K-1 and K-1 II will enable users to make in-camera adjustments to astrophotography images, including shading correction, fogging correction, background darkness, star brightness, celestial clarity, and fringe correction.

According to Ricoh, Astronomical Photo Assist is a premium feature that must be purchased and costs ¥11,000 for an activation key (about $70 at current exchange rates).

Although these astrophotography features appear to be Japan-only for now, a Ricoh representative tells us, “Ricoh Imaging Americas confirmed that the premium firmware features for the PENTAX K-1 and PENTAX K-1 Mark II will eventually be available to US customers.”

Firmware update 2.50 for both the K-1 and K-1 II is available for download from Ricoh’s website.



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On this day 2017: Nikon launches D850

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On this day 2017: Nikon launches D850


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As part of our twenty fifth anniversary, we’re looking back at some of the most significant cameras launched and reviewed during that period. Today’s pick was launched seven years ago today* and yet we’re only quite recently stepping out of its shadow.

The Nikon D850 is likely to be remembered as the high watermark of DSLR technology. We may yet still see impressive developments from Ricoh in the future (we’d love to see a significantly upgraded Pentax K-1 III), but the D850 was perhaps the green flash as the sun set on the DSLR as the dominant technology in the market.

Click here to read our Nikon D850 review

Why do we think it was such a big deal? Because it got just about everything right. Its 45MP sensor brought dual conversion gain to high pixel count sensors, meaning excellent dynamic range at base ISO and lower noise at high ISOs. Its autofocus system was one of the best we’ve ever seen on a DSLR: easy to use and highly dependable, with a good level of coverage. And then there was a body and user interface honed by years of iterative refinement, that made it easy to get the most out of the camera.

None of this is meant as a slight towards the other late-period DSLRs but the likes of Canon’s EOS 5DS and 5DSR didn’t present quite such a complete package of AF tracking, daylight DR and low-light quality as the Nikon did. With its ability to shoot at up to 9fps (if you used the optional battery grip), the D850 started to chip away at the idea that high megapixel cameras were specialized landscape and studio tools that would struggle with movement or less-than-perfect lighting. And that’s without even considering its 4K video capabilities.

In the seven years since the D850 was launched, mirrorless cameras have eclipsed most areas in which DSLRs once held the advantage. For example, the Z8 can shoot faster, autofocus more with more accuracy and precision, across a wider area of the frame and do so while shooting at much faster rates.

But, even though it outshines the D850 in most regards, the Z8 is still based around what we believe is a (significant) evolution of the same sensor, and its reputation still looms large enough for Nikon to explicitly market the Z8 as its “true successor.”

Nikon D850 sample gallery

Sample gallery
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*Actually seven years ago yesterday: we had to delay this article for a day to focus on the publishing the Z6III studio scene: the latest cameras taking precedence over our anniversary content.



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Nikon Z6III added to studio scene, making image quality clear

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Nikon Z6III added to studio scene, making image quality clear


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Photo: Richard Butler

We’ve just received a production Nikon Z6III and took it into our studio immediately to get a sense for how the sensor really performs.

Dynamic range tests have already been conducted, but these only give a limited insight into the image quality as a whole. As expected, our Exposure Latitude test – which mimics the effect of reducing exposure to capture a bright sunrise or sunset, then making use of the deep shadows – shows a difference if you use the very deepest shadows, just as the numerical DR tests imply.

Likewise, our ISO Invariance test shows there’s more of a benefit to be had from applying more amplification by raising the ISO setting to overcome the read noise, than there was in the Z6 II. This means there’s a bigger improvement when you move up to the higher gain step of the dual conversion gain sensor but, as with the Z6 II, little more to be gained beyond that.

These are pushing at the extreme of the sensor’s performance though. For most everyday photography, you don’t use the deepest shadows of the Raw files, so differences in read noise between sensors don’t play much of a role. In most of the tones of an image, sensor size plays a huge role, along with any (pretty rare) differences in light capturing efficiency.

Image Comparison
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As expected, the standard exposures look identical to those of the Z6 II. There are similar (or better) levels of detail at low ISO, in both JPEG and Raw. At higher ISO, the Z6III still looks essentially the same as the Z6II. Its fractionally higher level of read noise finally comes back to have an impact at very, very high ISO settings.

Overall, then, there is a read noise price to be paid for the camera’s faster sensor, in a way that slightly blunts the ultimate flexibility of the Raw files at low ISO and that results in fractionally more noise at ultra-high ISOs. But we suspect most people will more than happily pay this small price in return for a big boost in performance.



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