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Sigma 15mm F1.4 Diagonal Fisheye sample gallery: Night photography in the sub-arctic

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Sigma 15mm F1.4 Diagonal Fisheye sample gallery: Night photography in the sub-arctic


In late February, Sigma surprised us by announcing its 15mm F1.4 DG DN Diagonal Fisheye lens, an optic squarely aimed at astrophotography. Sensing an opportunity, we put the lens into the hands of José Francisco Salgado, a professional astrophotographer, just in time for a photography trip to the Canadian sub-arctic to shoot the aurora borealis.

An important note about these sample photos: When shooting sample galleries for lenses, we typically keep ISO values as low as possible to prevent image noise from affecting the apparent sharpness of images. By its very nature, astrophotography often requires higher ISO values, even with the fastest lenses. As a result, we asked José Francisco to capture his nighttime photos using ISO settings that were appropriate to the conditions. To allow for critical evaluation of sharpness, he also included several daytime photos in the gallery that were photographed at low ISO values.

What did he think of the lens? “Diagonal fisheye lenses are part of my arsenal to capture very wide sky subjects such as auroras and the Milky Way,” he told us. “The Sigma 15mm F1.4 DG DN is the fastest and sharpest diagonal fisheye lens I have ever used. Its focus lock is a feature that, as an astrophotographer, I have been wishing for for years.”

You can learn more about the lens here.

View the Sigma 15mm F1.4 DG DN Diagonal Fisheye sample gallery

Note: Please do not reproduce any of these images on a website or any newsletter/magazine without prior permission (see our copyright page). We make the originals available for private users to download to their own machines for personal examination or printing (in conjunction with this review); we do so in good faith, so please don’t abuse it.


José Francisco Salgado, PhD is an Emmy-nominated astronomer, night sky photographer, public speaker, and photo tour operator who creates multimedia works that communicate science in engaging ways. His Science & Symphony films through KV 265 have been presented in more than 260 concerts and 215 lectures in 21 countries.

José Francisco, a seasoned aurora photographer, leads his Borealis Science & Photo Tours in Yellowknife, Canada, where you can view, photograph, and learn about the Northern Lights.

You can follow him on Flickr, Instagram, 500px, Facebook, and Twitter





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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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