Sony a7S Astrophotography Review

Sony a7S Review

As soon as the Sony a7S was announced, I knew I had to try it for astrophotography. With a full frame sensor and ISO 409600, is it the best low light camera out there?

Introduction

The Sony a7S is the third variation of the full-frame mirrorless a7 series of cameras that Sony has recently released. First Sony released the 24.3 megapixel a7 and 36.4 megapixel a7R, the first mirrorless cameras with full-frame 24mm x 36mm sensors. The recently released a7S seems like sort of the oddball of the three a7 variations: It has only a 12.2 megapixel sensor and at the time of this writing, it costs almost $1000 more than the a7 and $200 more than the much higher resolution a7R. But with that 12.2 megapixel sensor comes some distinct advantages, especially for low-light photography and video.

12.2 Megapixels 

With the a7S, it seems like like you’re paying more for less. But even with a sensor resolution that is a third the resolution of the cheaper a7R, the a7S offers two things in return: sensitivity and 4K video (sort of*). The A7s has larger pixels than pretty much any consumer level full-frame digital camera. The larger pixel size means that each pixel can collect physically more light.  The more light per pixel, the better the signal to noise ratio for that pixel and so that pixel will more accurately detect the incoming light than a smaller pixel would. This means that, all other things being equal, the A7s should be capable of the best per pixel signal-to-noise ratio of any production camera. This means that it should arguably be the best camera for astrophotography yet.

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The 12.2 megapixel sensor in the a7S

Most high end DSLRs’ ISO sensitivity tops out at or 51200 or 102400. The a7S goes a full two stops more: it has a maximum ISO of 409600. Now for all practical purposes, 409600 is an ISO setting that’s probably not going to be used very much for final images, if at all, ever. ISO 409600 is only really applicable to really really dark scenes and the photos are sure to be really noisy, but it also indicates that the other higher ISOs of the a7S should be much cleaner than the competition.

*The a7S is capable of outputting 4:2:2 UHD 4K video via its HDMI port. This means that it’s not actually capable of shooting 4K unless you attach it to a portable external recorder. It can still record regular old HD video in 60i/60p/30p/24p at 1920 x 1080 and 120p at 1280 x 720 directly in the camera. In order to record the full 3840 x 2160 UHD 4k  video, you need to plug the a7S into a separate video recorder like the Atomos Shogun which will be available in late September. It should also be compatible with the soon-to-be-released production oriented Black Magic URSA HDMI.

A Low Light and Astrophotography Review

Per the usual Lonely Speck article, I’ll be concentrating almost exclusively on the low light capability of the a7S, particularly for landscape astrophotography. I wanted to push the a7S to some exposure extremes so I also got it with the fastest lens I could get my hands on: the Voigtlander 50mm f/1.1 Nokton. The extremely high sensitivity of the a7S in combination with the f/1.1 aperture of the Voigtlander should give us some ridiculous low-light capability for this review.

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The Voigtlander 50mm f/1.1 Nokton mounted with the Metabones Leica M to Sony E Adapter.

First Impressions

My current full-time travel kit is all Fujifilm, with the Fujifilm X-T1 as my primary body. By comparison, the a7S is very similar in size to the X-T1. Despite their visual similarities, they’re completely different cameras. Obviously the a7S has a larger full frame sensor than the APS-C sensor on the X-T1 and in turn they each have a completely different lens system. Everything about these two systems speaks of different design priorities. The X-T1 seems more oriented toward the still photography purists. The X-T1 has all dial controls with dedicated dials for all the major exposure settings while the Sony a7S has the standard M-S-A-P mode dial and a dedicated movie mode, just like pretty much any modern DLSR. As a result, the basic control layout of the a7S is very similar to pretty much any Canon or Nikon that I’ve used.

The a7S comes with two batteries, a welcome inclusion, especially since the battery life is rather short compared to most DSLRs (340 shots per charge). The included charger is also nice and compact, much nicer than the huge brick that came with my X-T1. In the a7S’s Time-Lapse app I was able to make 525 photos on a single charge, which is on par with what I can get shooting timelapse with my Fujifilm X-T1. I’m also happy to see that the a7S can be charged via micro USB, which is something that makes travel with the camera that much more convenient.

Size Comparison: Sony a7s vs. Fujifilm X-T1

Size Comparison: Sony a7s vs. Fujifilm X-T1

Build and Handling

The a7S looks and feels of extremely high quality materials. There’s just something about it that makes it feel more solid than pretty much any other camera I’ve used. It’s small size makes it very nice to handle. Paired with a small lens (i.e. not the Nokton), the a7S would be very nice to carry around all day. The grip is wider than the grip on the X-T1 and I think that it’s just as comfortable, just different. It has a nice rear thumb protrusion just like the X-T1 to make single handed holding much easier.

Where the grip could use improvement is when a7S is paired with larger full frame lenses, adapted from other camera mounts (a popular thing to do with the a7 series as the FE mount lens selection is rather small at the moment). With large third party lenses attached, the a7S feels a little bit imbalanced.

The Sony a7S mounted with the Rokinon 24mm f/1.4 Lens

The Sony a7S mounted with the Rokinon 24mm f/1.4 Lens

Unfortunately, the a7S is not weather sealed, unlike most other cameras in its price bracket. I shoot a lot in dusty conditions and weather sealing would have been a welcome feature for this camera. For now, I’ll keep the X-T1 as the hard-use camera.

The Finder and Monitor

The electronic viewfinder is excellent. It seems very similar in quality to the X-T1’s viewfinder. Transitioning between the two cameras, there’s almost no noticeable difference in the quality of the finder picture; they’re both excellent. The monitor on the back of the a7S is also very nice and I’m super happy that it’s tiltable both up and down for low mounted or overhead shots. I use the tiltable monitor on my X-T1 for nearly all of the astrophotos that I shoot so it’s great that Sony included one on all the a7 series of cameras.

The finder and monitor are both enabled by default. The LCD automatically switches off when you raise your eye to the finder. The monitor can only be disabled through the settings menu. The major downside of this setting is that it’s global and affects image review and menu operations too. This means that with the monitor disabled, if the user presses play to see their last shot, they will need to review it through the finder. This behavior differs from what I’m used to on the Fujifilm X-T1 where you can disable the monitor for normal shooting or playback independently: this allows the user to shoot with only the viewfinder but playback on the monitor screen.

With the a7S, it’s either shoot and review on the finder only, shoot and review on the LCD only, or keep both enabled all the time. To make matters even more disappointing, there is the ability to map “disable monitor” to a custom button but pressing it still leaves the LCD enabled and backlit, just all black pixels. It’s an essentially useless function. I’m inclined to just leave both the finder and monitor enabled all the time for most of my shooting so that I’m not stuck trying to change menu items while looking through the finder. Good thing Sony supplied two batteries.

In very low light the image feed from the sensor on the a7S is MUCH cleaner than the X-T1 and any other camera I have used. This feature makes it substantially nicer to focus in the dark which is a killer feature for astrophotography. More on this later.

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The a7S LCD tilts up for low-mounted shots.

Menu Interface

I have heard rumors about the Sony line of mirrorless cameras having clunky interfaces, so at first I was pretty skeptical of what the camera had to offer. My conclusion: it’s just different. Any user transitioning from Canon or Nikon or any other manufacturer will probably need an hour or so with the camera to familiarize themselves with the functionality. The same could be said of transitioning to any new brand. There are definitely some small quirks, but the a7S operates just as I would typically expect from any camera. The biggest thing for me was just getting used to the button locations (important when shooting in the dark) but it was pretty quick to learn. There’s also a lot of menu customization options, much more than pretty much any other camera I have used.

The camera also has a dedicated function (Fn) button. This is sort of like the “Q” button on Canon and Fuji cameras, used to quickly access certain functions of the camera. A step up from Canon and Fuji, the Fn button menu can be programmed with whichever functions the user desires. Similarly, the DISP button can be programmed to cycle through any number of alternate displays for the EVF and LCD.

Controls

By default, all of the most important exposure functions like ISO, shutter speed, and aperture are adjustable via three control dials. The front dial near your pointer finger is for aperture, the rear upper dial above the AF/MF button is for shutter speed, and the rear lower dial around the directional pad is for ISO. Exposure compensation has its own dedicated dial and allows for +/- 3 EV of compensation. I’m also happy to see that many of the buttons can be remapped to alternate functions. All of the most important quick access functions like Auto Exposure Lock, Live View magnify, White Balance, and Self-Timer/Continuous have dedicated positions. I added a function to the C3 button for changing metering modes and the down arrow for enabling focus peaking.

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I was unhappy to find that the shutter button has no tactile feedback. There is no noticeable half-press or full-press click on the shutter button, it’s just a spongy, springy button. I wish that it had an affirmative click so that it’s easier to “feel” when the camera is going to shoot. Where it felt the strangest was when using a long exposure with the first curtain electronic shutter enabled. In this scenario there is absolutely no audible or tactile feedback that the camera has started taking the photo. The only indicator is that the LCD will change to a black screen when exposing but it’s still a little strange starting an exposure and not being sure whether the camera is actually shooting.  It was a little bit annoying at first, but like all things on the camera I got used to it pretty quickly. The alternative is to disable the electronic first curtain but I just left the default setting for most of my time with the camera.

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The video record button is in the strangest of locations, especially for a camera that touts its 4K video capability. It’s on the side of the thumb grip, not a place where you can quickly mash it to start recording. What’s even more of a bother is that when the mode dial is set to movie recording, it completely disables the shutter button and instead just pops up a message on the LCD, a strange design decision on the part of Sony. For more practical movie shooting, I just leave the camera on the M, S, A or P mode for exposure and have the movie recording button enabled just in case I need it. This way, the camera can still take stills as usual but will start recording if I press the record button.

The mode dial also includes two memory mode settings, M1 and M2, which are programmable to recall any mode dial setting you wish to store. For example, if I wanted to have a mode dedicated to astrophotography, I would switch to M mode, program all my settings (long exposure, low f/number, high ISO, white balance, etc.) and then enter the camera settings menu and save it to one of the memory modes.

I’m disappointed that it’s not possible to re-map a more convenient button to be the record button. I’m sure that this complaint has been made by many other a7/a7R/a7S users. Hopefully Sony will listen to its customers and allow the function to be mapped to a more convenient location via a firmware update. Fingers crossed.

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Shutter Sound

In the default electronic first curtain mode, the a7S shutter sound makes a satisfying click that has a fast feel. I wish that my Fujifilm X-T1 had an electronic first curtain because it makes the a7S feel so much faster in operation for most daytime shooting. But as I mentioned before, first curtain shutter can make long exposures “feel weird” as there is no audible indication that the exposure has started; a sound is only heard when the shutter closes in first curtain mode.

In regular non-electronic curtain mode, the shutter sound is loud and feels slower. Overall, the shutter is noticeably louder compared to the Fujifilm X-T1. 

Luckily the camera has a silent mode that’s actually completely silent. The only camera that comes close is the Fujifilm X100s but even the X100s has a noticeable click. I have wondered for a while when professional oriented still cameras would start incorporating fully electronic shutter capability and the a7S is the first camera I’ve personally used that has it. The silent shutter mode will be an excellent feature for timelapse photographers in order to to reduce shutter wear and it should be perfect for event photographers (like wedding or performance photographers) who want to keep completely silent during the event. 

Image Quality

With a full frame sensor, the Sony’s a7 line already has an advantage over nearly every other mirrorless camera system. The larger sensor means that the a7S can take advantage of larger, full frame lenses. But as a new system, Sony only has 5 dedicated full-frame lenses available for the FE mount. Hopefully we will see Sony fill out their lens lineup with more competitive lenses in the near future.  In the meantime, its short flange focal distance also allows the a7S to use many other full frame lenses from nearly every other manufacturer via the use of adapters like the Metabones adapter I’m using here to mount the Voigtlander 50mm f/1.1 Nokton. I am also glad to see that most of my recommended lenses for Milky Way photography by Rokinon/Samyang are now available in the Sony E mount as well. The a7S’s built-in focus peaking feature also makes it very easy to manual focus lenses like the Voigtlander or Rokinon lenses.

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Sony a7S, 50mm at f/1.4, 10 seconds, ISO 800

Initial impressions of image quality are very high. The camera retains a tremendous amount of dynamic range when shooting in RAW format. Shadows retain very clean details and “Low” ISO images all the way up to ISO 12800 are practically noise free. Mounted with a fast lens, the photos from the a7S are just sublime. Let’s see how it does at the higher ISOs.

ISO Performance

Straight away, I wanted to try out ISO 409600. It’s hard to really grasp just how sensitive this ISO setting actually is until you can use it in real life. In this example, I was using an exposure of 8 seconds (just about typical for a full-frame 50mm Milky Way exposure). At ISO 409600 I was able to stop down to f/8. f/8! That’s just ridiculous. Now I wouldn’t recommend shooting the Milky Way at f/8 ever, but the fact that the a7S can capture this much detail at such a small aperture is mindblowing. Sure, it’s grainy and gritty but honestly not far off from ISO 25600 from any other camera I have used.

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ISO 409600 is so sensitive that it nearly overexposes the Milky Way at f/8. Sony a7S, 50mm f/1.1 at f/8, 8 seconds, ISO 409600.

I think that the practical, clean limit of the A7s is ISO 51200. At ISO 51200, shadows remain relatively clean and most of the fine detail in the image is retained. A clean ISO 51200 can allow users to use lenses as slow as f/8 for Milky Way photography (not that I would recommend it).

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ISO 51200 is the practical limit that I recommend for the a7S. Sony a7S, 50mm @ f/5.6, 8 seconds, ISO 51200

Sony a7S Astrophotography Review - ISO 51200

Sony a7S, 50mm @ f/8.0, 8 seconds, ISO 51200

That I was able to make as clean of images on the a7S at such high ISOs and small aperture settings is downright impressive and speaks to the quality of the camera’s sensor. Coupled with a fast aperture, astrophotos from the a7S are buttery smooth.

ISOless?

The sensor on the a7S is relatively ISOless between ISO 3200 and 51200. This means that for any given shutter speed and aperture setting, changing the ISO between these values shouldn’t change the relative level of noise in the image. The only thing that should change is the brightness of the overall image, signal and noise alike. Many new sensors like the Exmor CMOS sensor in a7S and the X-Trans II CMOS sensor in the Fujifilm X-T1 exhibit this behavior. What’s essentially happening inside the camera is that it’s exposing at a single sensitivity and then applying post-exposure gain to the data in order to brighten up the image to match the ISO setting that the user set.  In order to demonstrate this behavior, I made a series of exposures all at the same shutter speed and aperture, varying only the ISO from 1600 all the way up to 409600. Then, in post processing, all of the exposures were equalized for brightness in Adobe Lightroom and then placed side by side for comparison. Here’s what that looks like:

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ISOless? The Sony a7S shows a jump in gain at ISO 3200 and shows some built-in noise reduction from 102400 and above

This exercise allows us to evaluate the noise floor of the sensor at reasonable exposures and see how the a7S handles the highest of ISO settings. Below the blue line, we can see that the a7S is using a lower gain on the sensor and this resulted in overly noisy shadows and extra color noise at ISO 1600. Essentially, the lower ISO of 1600 is throwing out useful photon data. But once we get between the blue and red lines from ISO 3200 all the way up to ISO 51200, the image looks relatively clean by comparison. Noise levels are best between ISO 3200 and ISO 51200 and the photos look nearly identical, indicating that they are all made at the same sensor gain and then pushed in the camera. Basically it seems that the “true ISO” or unity gain ISO of the a7S is around ISO 3200 or so. Once we get above ISO 51200 we can see that the camera must be applying some kind of noise reduction because faint stars start to get lost and overall details look slightly muddier and overly smoothed.

From this test, we can see that there is little benefit from actually shooting above ISO 3200, so long as shadows aren’t clipped. It also supports my initial thoughts on the practical ISO limit as being ISO 51200. Even though the test shots were all shot in raw with no noise reduction applied, it’s apparent that the camera is still applying some post processing noise reduction above ISO 51200. What all this means is that I would recommend that a7S users shooting the stars stick to their typical shutter speed and aperture settings and use ISOs between 3200 and 51200, just adjusting as necessary just so that the histogram of the final exposure is relatively centered on the graph without clipping highlights or shadows.

Compared to the X-T1

Let’s try and see how much of an advantage the larger pixels on the a7S are when shooting at practical ISOs. I’ll compare the ISO performance of the Sony a7S directly to the Fujifilm X-T1. Some might think this is unfair because the sensor sizes are different, so the a7S is at a distinct advantage, but the X-T1’s X-Trans II sensor has some of the cleanest straight-out-of-camera high ISO photos of any camera on the market (if you don’t believe me, check out DPReview’s comparison tool) so I think it’s actually a really good match up.

I did not have the Canon 6D to make a direct comparison to the a7S, but the DPReview link above will allow you to directly compare the two.

In order to equalize the comparison between the X-T1 and the A7s, I will make sure the lens is at the same exact aperture diameter so that light gathering between the two cameras is identical.  This should ensure that we’re getting the same amount of photons to each sensor and the only differences between the shots should be from the sensor. The test sensitivity setting is ISO 6400 for both cameras and the exposure length is 10 seconds. Both of these cameras are relatively ISOless above ISO 1600 so it doesn’t really matter which ISO is chosen as long as it’s high enough to not clip the shadows and low enough to not blow out the highlights. ISO 6400 is a good practical number for this test because it makes for a relatively natural looking exposure of the Milky Way with an f/2.8 lens. It’s also the highest setting the X-T1 can go for RAW comparison purposes. The test scene is the same as the shots above and I’ve highlighted the 100% crop area which covers a 6° field of view of the sky.

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ISO test scene: the box indicates the crop area used for the comparison.

The files were equalized for gain differences, just like the ISOless test, and all noise reduction was disabled so the the comparison is representative of the RAW files.

NoiseComparison

The results are not as drastically different as I would have thought. The a7S resolves a slightly cleaner image: fainter stars are more visible and it actually looks a little sharper, even though the original a7S file is 12.2 megapixels versus 16.3 megapixels for the X-T1. This difference in resolution could also be due to a number of other things like camera shake, shutter slap, Lightroom’s de-mosaicing of X-Trans II files, or just missed focus with the X-T1.

The a7S image has more color noise than the X-T1, but the luminosity grain is cleaner on the a7S than the X-T1. The X-T1 image seems to have a fine smattering of grain that’s not present on the a7S. Overall, I like the image from the a7S slightly more, but I’m surprised that it’s not more substantially ahead of the X-T1. Compared to most other cameras, the a7S and the X-T1 are both spectacular performers. Where the a7S will gain a distinct advantage over the smaller sensor in the X-T1 is in the use of larger full-frame lenses for their full field of view and larger aperture diameters that can’t be found for smaller sensor cameras.

High ISO Live View and Video Feed

Where the Sony a7S really excels as a tool for astrophotographers is its live view feed, particularly with it’s S-log2 picture profile PP7 enabled (available via Menu>Camera>5>Picture Profile). The fact that it can push to ISO 409600 makes it possible to see and record real time video of the Milky Way. While this seems like somewhat of a novelty, it has a practical implication too: it’s possible to see and frame the Milky Way right from the Live View feed on the LCD. This makes it really really easy to focus and frame astrophotos with the a7S, more so than any camera I have ever used. I put together a video to demonstrate this capability and show you some of the video and timelapse results from the a7S.

Timelapse App

The a7S does not come with a built-in intervalometer by default, but it does have the capability to add an application called Time-Lapse through the Sony PlayMemories App Store for $9.99. The download of the app required creating an account with Sony and could be downloaded directly to the a7S via my home Wi-Fi network, just like a smartphone (cool!). There are a number of additional applications available for the a7S. For example: Multiple Exposure, Live View color grading, and even a Flickr app that allows you to share directly to your Flickr account from the phone.

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Time-Lapse app on the Sony a7S

The Time-Lapse App has a number of different presets, including a Night Sky preset. I mostly used the Custom function which allows setting all of the intervalometer parameters: the interval, total number of shots, whether or not the camera uses auto exposure (AE), and how quickly it will track changes in light. I tried using the AE functionality but didn’t shoot in any conditions with drastically changing light, so it wasn’t apparent to me how well it worked, as the exposure never needed to change. It allows saving the timelapse in either a 24p or 30p video file or to just save the stills. I recommend saving the stills as RAW and compiling in the computer for the best results. Unfortunately, it’s not possible to save both a video file and the stills at the same time within the app.

Functionality of the application is just as you would expect, but one strange behavior is that once the app is open, all the other functionality of the camera is disabled. Even turning the camera off and then on again will just open into the Time-Lapse app again.  Users must exit the app by opening the menu and navigating to “Exit Application” before the normal functionality of the camera can be restored. While this doesn’t seem to be a big deal, it means that if you put the camera away in your bag without exiting the app, it will open up in the app the next time you use the camera, preventing you from shooting normal photos right away. Definitely something to get used to.

All of the main exposure settings set within the Time-Lapse app are saved separately from the main camera user interface, too. This means that when you start the Time-Lapse app, it remembers the settings from your last timelapse, rather than pulling the settings originally set on the camera. This is a double-edged sword because it can mean that you can’t necessarily do a quick switch from regular shooting to Time-Lapse shooting and have the settings stay the same. You may need to reprogram all exposure settings for the current conditions once you enter the app.

Altogether it works just fine, and I’m happy with the overall functionality of the camera apps. I’m interested in seeing what applications will be offered in the future for Sony cameras.

Shooting Andromeda

The Time-Lapse app also allowed me to easily make a series of photos of Andromeda, the nearest full size galaxy to the Milky Way. A quick stack of the images made for a really clean shot of the galaxy all without any kind of tracking equipment, guiders or telescope stuff. Just the a7S and a 50mm lens.

Sony a7S, 50mm at f/4.0, 5 seconds, ISO 12800

Sony a7S, 50mm at f/4.0, 50 x 5 seconds, ISO 12800

Example Photos

The photos from this review were all made from either the Ancient Bristlecone Pine Forest and Trona Pinnacles in California. The trees of the forest are the oldest living things in the world, the oldest of which has been dated to have been alive for more than 4,700 years. We had rather cloudy skies during the forest night, so it was a constant battle to find clear views of the Milky Way. The moon was also a crescent after its last quarter, and it started rising a couple hours after midnight, which made for a nicely lit landscape for the final panorama stitch.

For Trona Pinnacles, the night was much clearer, and we had a nearly new moon, so the only thing lighting the foreground was the light pollution from the distant town of Trona. The Trona Pinnacles are calcium carbonate tufa formations left over from an ancient endorheic lake.  All of the images here were made with the Voigtlander 50mm f/1.1 Nokton.

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Ancient Bristlecone Pine Forest, Sony a7S 50mm at f/1.4, 10s, ISO 800

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Ancient Bristlecone Pine Forest, Sony a7S, 50mm at f/5.6, 1/100th, ISO 100

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Ancient Bristlecone Pine Forest, Sony a7S 50mm at f/1.4, 1/5000th, ISO 100

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Ancient Bristlecone Pine Forest, Sony a7S 50mm at f/4, 10s, ISO 12800

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Eastern Sierras from the Ancient Bristlecone Pine Forest, Sony a7S, 50mm at f/4, 18 x 10s stitch, ISO 12800

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Trona Pinnacles National Landmark, California, Sony a7S, 50mm at f/4, 14 x 8s stitch, ISO 12800

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Trona Pinnacles National Landmark, Sony a7S, 50mm at f/4, 12 x 8s stitch, ISO 12800

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Trona Pinnacles National Landmark, Sony a7S, 50mm at f/4, 12 x 10s stitch, ISO 12800

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Trona Pinnacles National Landmark, Sony a7S, 50mm at f/4, 10s, ISO 12800

If you want to learn how to make photographs like the ones above, check out my article on How to Photograph the Milky Way.

Conclusions

Overall, I’m pretty happy with the performance of the Sony a7S. Results can be spectacular even with modest lenses. ISO 409600 seems to be there more for bragging rights than anything else and I wouldn’t recommend anyone to try and shoot real photos at that speed if they can help it. But ISO 409600 also ends up becoming the a7S’s standout killer feature for astrophotography because it allows the camera to see the Milky Way in real-time for framing and focusing. The live view feed with the camera’s “Picture Profile 7″ is particularly great for framing in dark conditions because it provides a flat, bright picture that keeps shadow details visible, particularly in pitch dark conditions. This capability alone makes it easier to make astrophotos with the a7S than with any other camera I have used. Photo noise levels are excellent up to ISO 51200, above which details start to get muddied up by some sort of  built-in noise reduction that cannot be disabled in the settings.

For astrophotography the a7S seems to offer the cleanest image of any camera I have used so far. The larger pixels make for a slight bump in the cleanliness of the image at high ISOs that I haven’t seen in another camera. I wouldn’t say it’s a tremendous improvement in image quality over other very low noise offerings, but it’s still the best full frame camera I have seen. I had no hesitation shooting photographs stopped down to f/4.0 and ISO 12800 with the (relatively aberration heavy) 50mm f/1.1 Nokton.

Build quality is top notch and the overall experience with handling is just fine after getting used to it. Custom button settings and programmable function menus make the camera easy to customize to your style of shooting. The grip is very comfortable and most buttons and knobs are easily accessible. I had no problems using it in the pitch black night. The built-in applications are a welcome technological upgrade from the typical camera, and I’m happy to see that the Time-Lapse app makes for a functional, reliable built-in intervalometer.

The a7S has its quirks. The shutter button is spongy and the record button is in the most awful position and it’s not possible to use the shutter button to start recording when in movie mode. I’m also a little bit disappointed at the small number of dedicated full frame mirrorless FE mount lenses that are currently available for the a7 series of cameras. The lens lineup is slowly growing but it seems like it won’t be fully rounded out for another year or so.

It is, of course, possible to adapt numerous lenses from other lens mounts like Canon EF and Nikon F/G to the FE mount, but usually these lenses tend to be larger and more cumbersome to carry, especially when mounted on such a small camera body.  The more practical choice for third party lenses for the a7 series seems to come from the Leica M Rangefinder system. Lenses from Zeiss, Voigtlander and Leica for the M mount are relatively small but also are manual focus only and tend to come at comparably higher prices. That said, even the slower (f/4) FE mount zooms would work just fine for astrophotography with the Sony a7S since the ISO performance is still pretty clean from 3200 to 51200, so maybe I shouldn’t complain too much.

Again, the real killer feature is the fact that it’s possible to see the Milky Way in real time on the LCD or EVF. This makes focusing and framing super easy, far more than any other camera I have ever used. If you want the easiest to use camera for astrophotography, the a7S fits the bill.

You can find the a7S in stock here:

I would like to thank B&H for providing the a7S, 50mm and lens adaptor for this review. If you anticipate buying the Sony a7S and you enjoyed this review, please consider using the links in this article. It won’t cost you anything extra but Lonely Speck will get a small commission to help run the site free of banner ads. Thanks for your support.

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-Ian

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38 Responses

  1. Johnny Celaya October 12, 2014 / 12:11 am

    Hi Ian, thank you for all of the extremely helpful information on the website. It has helped me learn tremendously!

    When using the adapter on the A7S, does it change the effective focal length of the lens?

  2. David Martin September 18, 2014 / 11:35 am

    Hello Ian, I do sports photography and I am an editor for a local newspaper, how would that camera do under low light conditions in the gym? It sounds like they would be plenty bright, but may not be good for action shots. Also currently have a Canon Rebel T4i (which I use for sports and astrophotography), do you have any recommendations on the next step up for me as far as a camera that won’t break the bank? This seems like it would be an awesome camera to have (if it was only a little cheaper).

    • Ian Norman September 18, 2014 / 1:49 pm

      I think the a7S would function just fine in a gym but keep in mind that I didn’t evaluate the camera’s autofocus functionality. From what I understand the a7S autofocus system is not that fast compared to many DSLRs so you might find your T4i more useful in those scenarios.

  3. Cees van Kempen September 16, 2014 / 1:52 pm

    Hi Ian,

    Great review. I am not an astrophotographer, but a wildlife filmer and am interested in the a7s for night shoots.

    I have two questions.

    In your review you mention something about the red glow on the left caused by an amplifier(?) Can you explain?

    You show a nice hyperlapse in the video. How did you do that? Walking or with a long rail?

    • Ian Norman September 16, 2014 / 3:46 pm

      Amplifier glow is a problem on most digital camera at extreme ISO settings in warm conditions and dark settings. I was shooting on particularly warm nights so it was unavoidable. It’s usually not a problem on the still images at all as they are usually shot at lower ISO than the real-time view uses. I’ve never had it affect my stills so far.

      The hyperlapse was all manual, walking about 1 foot at a time. Set the tripod, frame the shot, shoot, move the tripod, frame the shot, shoot… repeat 100 times or more.

  4. Тарас Аргунов August 10, 2014 / 3:36 am

    Nice review. Ian, could you tell more about milky way shooting, please? I use 6D and Samyang 14/2.8, my town is situated in grey zone of light pollution atlas, but milky way isn’t so colourful as yours. For example: http://cs620131.vk.me/v620131727/118cb/EDQDJzIgHtc.jpg This is 30″, f/2.8 and iso 3200, one shot.
    Stars are bright, but nebulas look not so good. I want to shoot milky way better, because live in best conditions for this activity.
    Do you use deepskystacker or something like that?
    Sorry for off topic and my English. Thanks.

    • Ian Norman August 12, 2014 / 11:35 pm

      Great shot Tapac, it looks like you just need to work on your white balance settings. Shifting the white balance to a less blue setting should help you bring out more of the natural color of the milky way. I will be writing an article on color balance in my Astrophotography 101 course.

  5. Kay Burn Lim August 9, 2014 / 12:45 pm

    Great review! One issue I found with the time lapse app is that it won’t work with the electronic silent shutter mode. Am I doing something wrong perhaps? If so, I guess I would be better served by using an Intervalometer, perhaps even an IR app like the one on my Galaxy Note 3 together with the silent shutter to go easy on the mechanical shutter?

    • Ian Norman August 9, 2014 / 2:25 pm

      I have found this to be the case too. It works properly with first curtain electronic shutter but when enabling silent mode, it just defaults to the non-electronic shutter. A dissappointment for sure. I plan on writing a review in the Sony play memories app store outlining the problem.

    • Kay Burn Lim August 10, 2014 / 3:29 am

      I found a cheap wired solution here to stay with the silent shutter, at least until the app hopefully gets updated for silent mode. I have also found that ALL apps including the remote control will not work with silent shutter mode. Although it isn’t a huge concern for a few shots, for timelapse, the non mechanical shutter is a killer feature… at least there are cheap third party solutions. THis has been bar far the cheapest I found;

      http://www.ebay.com/itm/Shoot-RM-VPR1-Timer-Remote-Shutter-Control-Release-SONY-a7-a6000-Camera-/221504355247?pt=Camera_Camcorder_Remotes&hash=item3392b03baf

    • Ian Norman August 12, 2014 / 11:30 pm

      Thanks Kay, I think I’ll eventually get one of those eBay remotes for the a7S for sure.

  6. Anthony Lau August 5, 2014 / 7:00 pm

    Thank you for this superb review! You photo at Eastern Sierras are especially stunning and really show how A7S can handle astrophotography even under light pollution. May I ask if you ever have a chance to compare side-by-side A7R vs A7S in similar context?

    • Ian Norman August 5, 2014 / 10:23 pm

      I haven’t had both the a7S and a7R side by side but from what I have seen, the a7R is no slouch. I think that I would expect the extra resolution to provide a noticeable advantage in terms of image quality as long as it’s paired with a fast lens. If I can get the a7R and a7S side by side, I’ll be sure to post some comparisons. It would be a pretty interesting study in sensor pixel size.

  7. Gwangwook Kim August 5, 2014 / 6:26 pm

    Good review! One question, Are you check the red light sensitivity of A7s? I tried some astro photo by my Alpha7 (not s), red light sensitivity was very low, caused by lowpass filter, lower than canon DSLR.

    • Ian Norman August 5, 2014 / 10:15 pm

      I feel like the a7S seems to perform similarly to most other cameras I have used in terms of color but I haven’t tried doing any sort of direct test. It managed to pick up some very faint magenta airglow and also captured most of the diverse colors in the rho ophichi region so I feel like the performance was pretty good for my taste.

  8. Paul August 5, 2014 / 3:12 pm

    That does seem quite a bit sharper than the star-fields that you captured with the 6d. It’s too bad the camera is much more expensive :(

    • Ian Norman August 5, 2014 / 4:09 pm

      Yes, the Canon 6D is still a hard camera to beat when price is factored into the mix. The a7S might be better slightly better for low light but if that’s the only unit of measure, the 6D is a steal by comparison.

  9. HFLM August 5, 2014 / 5:36 am

    Hi,

    very nice test. Did you have a chance to test the Nikon DF? David Kingham had used it and it performed great. It’s ISO range is extended compared to the D610 and D8xx, too.

    • Ian Norman August 5, 2014 / 12:14 pm

      I have not used a Df unfortunately so I can’t report on how it fares. Basically its getting to the point now where nearly every new camera has great images and the real thing that sets them apart is the user experience.

      There were a few things about the Df that made me steer clear. The control layout is particularly strange, especially the mixing of mode dial and dedicated shutter speed dial. It was a lot larger than I expected once they announced it. I (think we all) expected that it would be like an old Nikon F but it ended up being so much bigger. I am perhaps a little swayed toward using smaller mirrorless designs now that I have thoroughly experienced Fujifilm and Sony’s offerings. Wish the a7 series had more lenses though. Time will tell how all these companies develop their camera lines.

  10. Gene Kim August 2, 2014 / 1:11 pm

    Very very nice images! how can you have your foreground so bright while you are in the dark area? Seems like you have gotten great details on both your milky way and foreground! Any tips for that??

    Thanks,

    • Ian Norman August 2, 2014 / 7:53 pm

      Thanks Gene!

      Trona Pinnacles is a very dark sky area but there is a small town just to the north that casts a little bit of orange light pollution glow. You can see how the rocks are more brightly lit than the ground beneath them. This tiny bit of extra light helped fill in the surrounding foreground nicely. The a7S RAW files also respond very well to pushing in post processing so it was very easy to bring up the shadows just a bit to retain detail in the foreground.

      As far as tips, in very very dark conditions (darker than Trona Pinnacles) I recommend trying some light painting (while exposing use your flashlight to paint the foreground). Or, if you prefer a more natural look, try compositing in Photoshop two separate exposures. One standard exposure for the sky (30 seconds or less-ish) and another much longer exposure for the darker foreground (4-8 minutes).

    • Gene Kim August 2, 2014 / 8:34 pm

      Thank you so much for your considerate reply :)
      Theses images are really really awesome indeed!
      What do you think of A7s as landscape astrophotography camera? would you prefer this model over any other full frame camera from canon of nikon? for instance canon 6D or nikon D610 etc? If I am not wrong A7s does have better(or much better maybe??) high ISO performance compared to those others, but have low numbers of pixels in sensor.

      Just curious how you think about choosing a camera when you would like to move up to full frame or pro-grade level body from a mid-level body.

      Thanks again!

    • Ian Norman August 2, 2014 / 9:13 pm

      Gene,

      I’m likely going to hold on to the a7S mostly for the fact that it’s so easy to frame and focus the photograph. It is a really huge benefit for landscape astrophotography.

      I could see a few photographers taking issue with the lower resolution sensor but I really don’t think it’s a problem. Images are very clean and should print very nicely at large sizes. Personally, 99% of my images are distributed digitally anyway so overall number of megapixels matters much less to me.

      Direct comparisons to the 6D or D610 in terms of image quality I’m sure are a toss up, especially with similar lenses and settings. Nearly every modern full-frame digital camera can make amazing astrophotos, especially when paired with a decent lens. If I was looking for my first full-frame camera for astrophotography specifically, I would choose the a7S paired with a good Rokinon manual focus lens. If I wanted it for other uses like sports or action photography, I might be more inclined to consider the Canon or Nikon, their autofocus lens systems are more mature so there is a larger pool native system lenses to choose from.

    • Gene Kim August 4, 2014 / 11:08 am

      Thanks for your opinion!

  11. Justin Lewis August 1, 2014 / 11:41 pm

    How would you see the pootential for specialist time lapse fuctionality partcularly bulb ramping without the avaliability of accessories/devices or software like magic lantern? Or is the image quality and latitude so good that this effect can be achieved in post only after some shutter dragging in camera?

    • Ian Norman August 2, 2014 / 7:46 pm

      I’m still trying to find an opportunity to try out the Time-Lapse app’s auto exposure ramping mode but I imagine that it would work pretty well. If it does, I could see it operating similarly enough to AETTR in Magic Lantern to be able to shoot unattended day to night or night to day timelapse sequences. I’ll try to append my findings to this review and shoot you an email with the results.

  12. evilteddie August 1, 2014 / 7:06 am

    You can set the FINDER/MONITOR to Auto, Viewfinder or Monitor. Setting it to Viewfinder turns off the LCD.

    • Ian Norman August 2, 2014 / 7:43 pm

      Evilteddie,

      Thank you! This was pointed out to me by one of the readers on Petapixel too. I’ll amend the review for the correction. I only wish this function could be mapped to a custom button. Altogether, it’s a pretty minor gripe I have found. Even with the Monitor enabled, I still managed to get over 500 shots so that’s a huge plus. I imagine that any more critical applications would call for either the battery grip or other external power anyways. 500 shots is more than enough for most timelapse sequences.

  13. Rishio July 30, 2014 / 11:33 am

    Wonderful piece. I’m confused a bit about your ISO measurements. It seems that the A7s files look better at ISO 3200 versus 1600. Are you saying that the natve ISO for the A7s in both photography and video is 3200 and does that mean a photograph shot at ISO 3200 will come out cleaner than a photo shot at ISO 100?

    • Ian Norman July 30, 2014 / 1:25 pm

      Yes. For a given shutter speed and f/number, ISO 3200 is cleaner than ISO 100. However, if you are shooting with auto metering, where ISO 100 would have a longer shutter/ larger aperture, ISO 3200 could end up worse because of the differences in overall signal.

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