Sony RX100 Series Astrophotography Review

Sony RX100 Series Astrophotography Review

In this review, we push the low-light limits of Sony’s premium compact point and shoot. We love the idea of a truly pocketable camera that can also capture photos of the Milky Way, but how good is the Sony RX100 series really? Can it actually compete with a large sensor DSLR or interchangeable lens mirrorless camera?

Introduction

When we put five of the most well regarded point and shoot cameras to a low-light camera battle, there was one camera that seemed to stand out above the rest: the Sony RX100III. We liked it so much that we bought one for our everyday camera kit.

While I personally still prefer using a larger, interchangeable lens camera for my primary astrophotography camera, I wanted a point and shoot that could serve as a real backup camera with no compromise in performance. Our RX100III has traveled with us all over the world over the last year as a backup camera. Many of the product photos and some of video footage that you may have seen on Lonely Speck over the last year was shot on the RX100III. You can also check out my girlfriend’s thoughts on the RX100III on her review at northtosouth.us.

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Until recently, the little point and shoot mostly fulfilled the role as the “behind the scenes” camera for us, never really being used for the “serious” shots. But recently, while on our current roadtrip across the US, my Sony a7II encountered a problem that forced me to send it in to repair. With my primary camera body out of commission, the RX100III has since taken up the role of “astrophotography camera.” With only the RX100III available to me, I figured I should make the best of it and use the opportunity to finish my long overdue review of the little point and shoot.

Sony has, at the time of this writing, released no less than four iterations of the Sony RX100. To our liking, all four versions of the RX100 use a 1″ Exmor type CMOS sensor and a fast f/1.8 lens. Here are some of the key features that vary between each camera:

  • Sony RX100
  • 1″ Sony Exmor 20.2MP Sensor
  • 28-100mm (equiv.) f/1.8-f/4.9 lens
  • pop-up flash
[one_half_last]
  • Sony RX100II
    • 1″ Sony Exmor R 20.2MP Sensor
    • 28-100mm (equiv.) f/1.8-f/4.9 lens
    • pop-up flash
    • accessory hot-shoe
    • tilt-screen
[/one_half_last]Sony RX100 Series of Cameras

  • Sony RX100III
    • 1″ Sony Exmor R 20.1MP Sensor
    • 24-70mm (equiv.) f/1.8-2.8 lens
    • pop-up flash
    • electronic viewfinder
    • tilt-screen
[one_half_last]
  • Sony RX100IV
    • 1″ Sony Exmor RS 20.1MP Sensor
    • 24-70mm (equiv.) f/1.8-2.8 lens
    • pop-up flash
    • electronic viewfinder
    • tilt-screen
    • 4K and high speed video
[/one_half_last]

While the newer versions of the camera should offer slightly improved performance, in practice each camera has very similar low-light performance (dpreview.com comparison test). If you want to read more about my first impressions of the RX100III in particular, check out our original Five Camera Low-Light Battle that helped us choose the RX100III as our dedicated pocket cam.

If you are deciding which RX100 version to buy and you’d like the best astrophotography experience, consider the RX100II, RX100III or RX100IV for their tilt screens, a feature that makes for a more enjoyable astrophotography experience. It’s easier to point the camera upwards to the stars with a tilt screen, especially if you’re setting up your tripod low to the ground.

User Experience

I’ll start off by saying that even after more than a year with Sony mirrorless cameras, I still don’t really like Sony’s menu system when compared to other competing camera systems like those from Canon and Fujifilm. I’ve already said it in my Sony a7S review and I’ll say it again here. Sony’s menus are way too long and disorganized. The one redeeming quality, in this regard, of any of the Sony RX or Sony Alpha series cameras is that there are at least lot of options to customize buttons and a user programmable quick access function (Fn) menu. Anything that can be done to reduce the need to enter the main menu is a welcome feature.

The RX100 series features user customizable Fn menu that gives quick access to most used functions.

The RX100 series features a user customizable Fn menu that gives quick access to your most used functions.

The RX100 series cameras share an identical user interface as the larger, interchangeable lens alpha series cameras like the a7 and a6000. It’s like they squeezed the power of their “serious” cameras into this tiny pocketable thing. With that come a few benefits and drawbacks. The primary benefit is that the RX100 series cameras have no missing features. Everything you would expect out of an enthusiast camera (like manual controls, manual focus, RAW, built-in image stabilization, custom white balance, etc.) is available on the RX100 series.

All of the controls operate mostly the same as any other Sony Alpha series camera but there are some obvious size limitations that limit a direct 1:1 control scheme when compared to the larger Sony cameras. All the controls are packed on to the right rear side of the camera. The smaller form factor of the camera does limit how quickly it can be operated. I’d say the camera has a little bit more of a learning curve to get used to changing certain settings but overall, a well-customized Fn-menu should make for relatively fast changes to the most used settings. I found that the optional leather case makes the camera more comfortable to handle and Sony also offers an optional finger grip which should be even better.

One stand out feature is how easy it is to manual focus the RX100. Once set to manual focus mode via the Fn menu, turning the ring on the outer circumference of the lens changes the focus. If Focus Assist mode is enabled, the camera automatically magnifies the view to help with fine focus. The RX100III also remembers the focus point no matter which shooting or playback mode you subsequently change to. Entering playback to review the photos or opening the Time Lapse App will not change the focus point once it’s set. This behavior makes it nice to set focus, make a test shot, check focus, and then adjust if necessary. This is one of the behaviors of the camera that initially helped me choose the RX100III over the competing Canon G7X which doesn’t like to hold focus in these situations.

Astrophotography Settings

I’ve had numerous experiences shooting astrophotography with the Sony RX100III and in every cases I’ve had no issues getting what I wanted out of the camera. For reference, here are some of the settings that I always check on the RX100III before shooting astrophotography:

  • RAW
  • Manual Focus
  • ND Filter: Off
  • White Balance: Daylight or Custom: 3900K
  • Long Exposure NR: Off
  • SteadyShot: Off
  • MF Assist: On
  • Peaking: Off
  • Live View Display Setting Effect: On
  • Self-Timer: 2 seconds (reduce camera shake)
  • Manual Exposure

And as far as exposure settings on the RX100, I’ll generally shoot zoomed all the way out with the following settings:

  • 20-25 seconds
  • f/1.8
  • ISO 1600

For shutter speed, 20 to 25 seconds is long enough to make sure the camera is collecting enough light but short enough that star trails won’t be too apparent in the final image.

For aperture, f/1.8 ensures that the lens opening is as large as possible to collect as much light as possible. I’ve tried a bunch of different aperture settings to see if there’s a noticeable increase in image quality when shooting astrophotos but f/1.8 is still very sharp and gives the best low-light results. I’ll dive more into the details of the RX100III lens performance in the next section on image quality.

For ISO, I’ve found that ISO 1600 generally gives adequate image brightness when shooting at f/1.8 so that results look bright enough straight out of the camera to be able to successfully gauge composition and focus. We’ll take a closer look at sensor performance and ISO settings next.

Image Quality

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Sony RX100III, 15 seconds, f/2, ISO 1600

I’ll just start by saying that I’m absolutely blown away by the image quality of the RX100 series. It is very difficult to tell the difference between photos from this little camera and a typical large sensor DSLR. Even in the extremely low-light conditions that astrophotography requires, the RX100 series absolutely shines. It really is that good.

It is very difficult to tell the difference between photos from this little camera and a typical large sensor DSLR.

ISO-Invariance

One of the experiments that I like to run on cameras that I use for astrophotography is an ISO-invariance test. I performed a similar test on the Sony a7S (full review). The point of the ISO-invariance test is to evaluate which ISO setting is most beneficial to use on any given camera. In short, there is usually a certain ISO setting threshold above which any given camera will show its best low-light performance. The way we test this is by capturing the same image at each ISO setting while using the same shutter time and f/number between images. Then in post-processing we re-adjust each image in Adobe Lightroom to be equal brightness and then compare the levels of relative noise (grain) in the images.

rx100iii-iso-invariance-full

Milky Way (Unedited) RX100III, f/1.8, 20 seconds, ISO 1600. Box indicates test area.

For the ISO-invariance test, I made exposures of this scene at Trona Pinnacles, California. All the exposures used 20 seconds at f/1.8. I made the photos at each whole stop ISO setting from ISO 125 to ISO 12800. All the test images were recorded in RAW with all forms of noise reduction disabled for this test.

rx-100-iii-iso-invariance

RX100III ISO-Invariance Test, 8.8mm, f/1.8, 20 seconds

First, I’d like to emphasize just how impressively the RX100III performs in these conditions. The results look like they were made on a larger sensor, no doubt thanks to the fast f/1.8 lens. Upon initial inspection, all of the ISO settings look pretty similar: the Sony Exmor sensor seems relatively ISO-invariant. But upon closer inspection, there are subtle signs that the camera is doing different things at different ISOs. ISO 125 appears to have the heaviest amount of grain compared to the the rest. From ISO 200 through ISO 800, grain is reduced but there are still noticeable hot pixels, particularly in the shadow areas. From ISO 1600 to ISO 3200, most of the strong hot pixels are gone and it looks like the grain profile is a little smoother. Finally, at ISO 6400 and ISO 12800, the camera appears to be applying some heavier noise reduction. At these two highest ISOs, grain looks smoothed out and details seems slightly softer.

I tend to like the results from ISO 1600 to ISO 3200 the most so I’ve made it a practice to keep the setting right at 1600 for most of my photos. I find that ISO 1600 gives clean looking and adequately bright images straight out of the camera and I feel like it’s not so high that I’m sacrificing dynamic range on the bright end of the spectrum.

Lens Performance

The Sony RX100III has an impressively fast lens. When zoomed out, it’s an 8.8mm f/1.8. with a field of view similar to the classic 24mm lens field of view on a full-frame camera. It’s a nice wide field of view and the extra low f/number of f/1.8 helps tremendously with low-light conditions. One of the more prominent concerns with any fast lens, when used for astrophotography, is the presence of aberrations (our article on aberrations) like coma and astigmatism. Coma and astigmatism can distort the shape of the stars and can be distracting elements in an astrophoto. In this regard, the RX100III isn’t perfect.

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Sony RX100III, 20 seconds, f/1.8, ISO 1600

There is noticeable coma in the corners of the image, giving most bright stars a small tail. Unfortunately, the aberrations don’t seem to improve very much when stopping down. Even stopping one full stop to f/2.5 and the coma is still apparent.

rx100iii-aberration-coma-astrophotography

The RX100III series shows some signs of coma aberration in the corners of the frame.

Now even though the lens on the RX100III isn’t perfect in this regard, the size of the aberration is small enough to be almost unnoticeable at typical viewing distances. Perhaps it’s not the best camera for the ultra-pixel-peeper but if we were really concerned about the finest resolution and aberration performance, we’d probably be reviewing the Canon 5DSR coupled with a Zeiss 55mm f/1.4 Otus.

I think the level of aberrations present in the RX100 series cameras is perfectly acceptable for most usage and it’s unexpectedly good for a point and shoot.

Sample Images

While the RX100III has only recently fulfilled the role of “primary camera” while my a7II is being repaired, I’ve tried to remember to pull it out of the bag whenever I’m shooting astrophotos. Over the course of the 2015 summer, we’ve had the opportunity to shoot astrophotos with the RX100III in California, New Mexico, Wyoming, Alberta, New York, West Virginia and Kentucky. (My girlfriend Diana and I are currently on a long road trip across the USA. Follow our trip progress on North to South.) Here’s a run down of all the best night sky photos we have managed to capture:

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RX100III, 20 seconds, f/1.8, ISO 1600

The first time I used the RX100 for photographing the Milky Way was from Trona Pinnacles, California. The National Natural Landmark is still one of my absolute favorite spots for photography and the RX100III did a great job at capturing it. For a single frame with nothing but the default Lightroom noise reduction, it’s amazing how much detail is visible in the shadows of the image.

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RX100III, 25 seconds, f/2, ISO 1600, two frame panorama

One of the early stops on our roadtrip across the United States that had clear enough weather for astrophotography was at White Sands National Monument in New Mexico. While I spend most of my time shooting photos with the a7II at the time, I managed to make a few frames with the RX100III including the two frame panoramic stitch above and the north facing shot of our tent situated between the rows of sand dunes.

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RX100III, 25 seconds, f/2, ISO 1600

What impressed me most about the photos at White Sands was just how much shadow detail is visible in the photos. For such a small camera, it seemed to nearly match the performance of my much larger a7II with the Voigtländer 15mm f/4.5 lens that I was reviewing the same night. That might be a bold claim, but I really think the photos from the RX100III are that impressive.

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RX100III, 10 seconds, f/2, ISO 1250

Our next best opportunity to photograph the stars was in Yellowstone National Park, Wyoming on June 22, 2015 where we were lucky enough to be shooting photos during a rare solar flare that created one of the most powerful aurora displays in decades. My girlfriend Diana captured this view of the aurora borealis with the RX100III from the comfort of the car while I messed around with my a7II just out of the frame to the left. We also happened to meet up with fellow photographer David Kingham shortly after the above photo was made. Turned out to be a good night.

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RX100III, 6 seconds, f/2, ISO 1600

Adjacent to Yellowstone is the Grand Teton National Park where I used the RX100III to capture some “behind the scenes” shots of my a7II shooting some blue-hour photos. (It’s mounted with the Rokinon 24mm f/1.4 in case you’re wondering.) I also set up the RX100III to shoot a short timelapse with the optionally installable Time Lapse Playmemories App.

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RX100III, 25×10 seconds stacked, f/2, ISO 1600

The Time Lapse App allowed me to capture a number of frames which I later stacked in Photoshop to create the above short star-trails image. I’ve personally grown to enjoy Sony’s built-in Time Lapse app as my preferred method to capture timelapse on all of my Sony cameras. It’s very consistent and is more convenient than an external intervalometer.

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RX100III, 20 seconds, f/2, ISO 1600

From Yellowstone and the Grand Tetons, we continued our road trip north to Waterton Lakes National Park in Alberta, Canada. Waterton Lakes is adjacent to Glacier National Park but we decided to spend the night “on the Canadian side.” The moon was a waxing crescent at the time so the skies remained blue in the early twilight.

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RX100III, 15 seconds, f/2.0, ISO 5000

We didn’t get another opportunity to shoot the Milky Way again until much later in our road trip when we arrived in Old Forge, New York. During our travels through New England, we happened to run into another photographer and reader of Lonely Speck, Tim Leach (Tim’s Instagram). Tim was kind enough to host us the following week at his family’s camp, Adirondack Woodcraft Camps.

The camp ended up being a spectacular spot to shoot astrophotos. While I personally spent most of my time shooting with the Sony a7II (what would be my last photos with the a7II before it died and needed to be sent in for repair), but Diana shot a bunch of astrophotos with the RX100III, including the above shot from the shore of Lake Kan-Ac-To of the galactic center graced by a meteor.

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RX100III, 20 seconds, f/1.8, ISO 1600

After New York, we continued south, with our next opportunity to shoot astrophotos in West Virginia. I’ve read about West Virginia many times as being one of the best places in the American East Coast for astrophotography. West Virginia is mostly rural country side and mountains so the skies are generally nice and dark. We ended up staying at an Airbnb for a couple nights in a renovated barn turned cabin near Seneca Rocks, West Virginia. I spent our first night capturing the stars from the barn and the second from the nearby Spruce Knob Mountain.

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RX100III, 25 seconds, f/1.8, ISO 1600

I found out about Spruce Knob Mountain from The Mountain Institute website. It turned out to be an excellent location with nearly 360 degree views of the surrounding area, dark skies and clear air. I took the opportunity to capture this self portrait and happened to catch a meteor in top right of the frame.

Stacking at 70mm: Before and After

While on Spruce Knob, I also figured I should try out the RX100III at its other focal lengths. The lens zooms but it’s fastest when zoomed-out at 8.8mm so I never really bothered to use it zoomed-in until that night. Zooming-in to 25.7mm (70mm equivalent) ends up slowing down the lens a full two stops to f/2.8 so it’s certainly not as good of a low-light performer when zoomed in.

In addition to slowing the lens two stops, zooming in forced me to use a shorter shutter speed of 10 seconds so I was losing a full three stops of light. Single frames came out pretty noisy with noticeable pink glow on the edges of the frame and loads of noise. That said, I still attempted a noise reduction stack of the galactic center with decent results. Check out the before and after above. It required a stack of 8 images total to achieve the final image.

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Sony RX100III, 8×13 seconds, f/1.8, ISO 1600

After West Virginia, we stopped in Kentucky’s Daniel Boone National Forest. The moon was entering its early cycle so I shot my photos over Cave Run Lake with the crescent moon in full view along side the Milky Way galactic center. Because of the extra light pollution from the moon, I decided to create some more image stacks for my final two images to help with post processing results. For more details on how I use image stacking to reduce noise, check out my video tutorial.

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Sony RX100III, 4×10 seconds, f/1.8, ISO 1600

I have had a genuinely good experience with the RX100III. It’s strange seeing these images knowing they were made with such a small camera and when I look at the camera in my hands, it’s sometimes hard to take it completely seriously. It looks like a toy when compared to my “real” interchangeable lens camera but the photos it produces lets you know it’s not playing around.

Conclusion and Recommendation

I can think of no other camera currently on the market that offers the same level of control, ease of use, and image quality in such a small package. Sony put all the right things into the RX100 series and it has made for a camera that outperforms nearly all of the expectations I usually have for something so small. It’s the ultimate backpacker astrophotography camera. If I was strapped for weight and wanted the lightest, most capable camera out of the box, I’d bring an RX100. Diana also thinks it’s more stylish than any of my other other cameras so there’s that, too.

Its small size creates a little more of a learning curve in regards to controls and the buttons can feel cramped when changing a lot of settings consecutively but it seems like a small compromise knowing the camera is truly pocketable. It’s lens isn’t the perfect performer in regards to coma, but it’s f/1.8 aperture enables the RX100 series to do things few other pocket cameras can. The RX100 series cameras are a great choice for the role of pocket astrophotography camera.

Sony RX100 Series Pros:

  • Wide angle f/1.8 lens
  • Excellent low light performance
  • Full-featured manual controls
  • Easy Manual Focus
  • Optional Built-In Intervalometer (via Time Lapse Playmemories App)
  • Tilt Screen (RX100II, RX100III and RX100IV Only)

Sony RX100 Series Cons:

  • Moderate coma aberration at f/1.8
  • Small size makes for cramped controls
  • Smooth body difficult to grip (Optional Leather Half Case or AGR2 Grip recommended)

Sony RX100 Series
Verdict: HIGHLY RECOMMENDED (5/5)

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-Ian

84 Responses

  1. Rani February 19, 2018 / 5:36 am

    Hi!!
    I just bought the Sony x100 iv. I was just wondering, how do you put the shutter speed on 20 or 25 seconds (my camera is on manual mode) I really can’t finds these settings.
    I’m sorry for my stupid question, but I searched for more then an hour :p
    Hope you can help me!

    Thank you very much,

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