How to Fix Sony Star Eater on the a7SII and a7RII (Continuous Shutter Mode Workaround)

How to Fix Sony Star Eater: a7SII and a7RII Alas, a partial fix to the dreaded “star eater” issue has been found for the a7SII and a7RII! The quick version: enable continuous shutter drive mode. Read more to learn about the “star eater” issue and the limitations of this partial fix.

Sony’s a7SII and a7RII have an issue that affects astrophotography when they’re used for exposures of 4 seconds and longer. Photographs of the night sky made with these cameras (especially the a7SII) are subject to a built-in processing that mistakes stars for noise and “eats” them or reduces their brightness. The issue also affects other Sony Alpha cameras in different scenarios.

The result of the issue is an astrophoto with reduced number of visible stars and an appearance of reduced resolution in the night sky. Stars are often also color shifted to false colors as a result of the problem. Since the issue affects stars at the pixel level, the problem is especially prevalent on the relatively low-resolution sensor of the a7SII. I have documented this issue thoroughly and noted how it affects most Sony Alpha cameras on my post about the so-called “star eater” problem. With a little bit of searching, you can find many other posts about the issue across the astrophotography and photography communities that confirm the problem.

One of the best sets of analyses of the issue came from Jim Kasson’s blog posts. He shows that with a frequency analysis of a color channel on the a7RII and a7SII, exposures of 4s and longer have attenuation at higher spatial frequencies. Basically, small bright pixels are filtered out. For a long time, this has been a problem a7RII and a7SII users have had to live with for months. But now, we have Jim Kasson to thank for making us aware of a partial fix.

The Workaround

Sony a7SII Continuous Drive Mode

Star Eater Workaround: Enable Continuous Drive Shutter Mode

In a December 2017 post, Jim Kasson talked about a potential workaround on the a7RII. The fix is certainly counter-intuitive: enabling continuous drive mode while shooting long exposures. In his analysis, Jim shows that by enabling the continuous drive mode, the a7RII no longer exhibits the same behavior of the star-eating algorithm. Jim’s original analysis was only of the a7RII so I was curious to see if the same workaround would work on the a7SII. I had a friend supply some sample dark-frames from his a7SII and I took a close look at the files. Sure enough, enabling continuous mode seemed to prevent the star eater problem from occurring. I sent the frames to Jim for his final analysis of the a7SII star eater workaround which he has published here.

  • So the good news: a7RII and a7SII users can circumvent the Sony star eater issue by shooting with continuous shutter mode enabled. Either regular “Continuous” or “Continuous Speed Priority” shutter modes will work.
  • The bad news: by enabling continuous shutter mode, the color depth of the raw files is reduced to 12-bit. This means that the file is losing some dynamic range capability and may show some increase in noise. In all practicality, the results should be more desirable for astrophotography than the star-eaten files.
  • Another problem that persists: Bulb exposures are still affected because continuous shutter mode cannot be enabled in Bulb mode and vice-versa. Furthermore, the new a7RIII is still affected, regardless of shutter drive mode. 

Closing Thoughts

Why didn’t we find this earlier?

It’s extremely well hidden. Under no circumstances does usually it make sense to shoot with continuous shutter modes while shooting long exposures. Normally, it’s a shutter mode reserved for sports and wildlife shooting. There isn’t a single reason to enable continuous shutter mode for astrophotography since our shutter times tend to be very very long.

But now that it’s out, this workaround is a welcome find for owners of the a7RII and a7SII who enjoy shooting astrophotography but it’s still only a partial fix. Using the workaround, bit-depth is slightly reduced, limiting the dynamic range of the resulting photographs. It’s also unfortunate that the problem still persists in Bulb mode and there’s no workaround for Bulb shooting known at this time. Ultimately, it’s dreadfully disappointing that this issue even exists in the first place. It’s a shame that Sony still has not issued a firmware fix to allow us to disable the spatial filtering altogether. I and several other astrophotographers are supporters of the open petition to Sony to fix the star eater issue altogether.

For a more complete documentation, see my article and open letter to Sony about the star eater issue.

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Lonely Speck is my full-time job. It’s been an amazing experience for us to see a community develop around learning astrophotography and we’re so happy to be a small part of it. I have learned that amazing things happen when you ask for help so remember that we are always here for you. If you have any questions about photography or just want to share a story, contact us! If you find the articles here helpful, consider helping us out with a donation. Donate Thanks so much for being a part of our astrophotography adventure. -Ian

46 Responses

  1. Barry Chall March 16, 2018 / 2:39 pm

    I just wanted to offer a slightly different perspective on the star eater issue. I think that the significance of it is directly relative to what you plan to use your night sky pictures for. If your stills are for printing, stacking, and close examination, then it may indeed be of significance- in some cases. However, in my case, I’m only interested in time lapsing for use in films. Just my opinion, but for that application, star eater is a total non issue. I shoot with two A7RIIs and one A7SII. I have found that in some scenes, it’s probably there a bit, but in others, I really don’t believe it is with either the RII or SII. And, if it does exist, it’s so inconsequential as to be meaningless. I often shoot at very high ISOs, often 12800 for an average of 15 to 20 seconds, depending on the lens. Maybe this is a factor, I don’t know. I’ve had people contact me after seeing a recent film on my YouTube channel and express tremendous relief after seeing the output from the Sony cameras. After reading all the doom and gloom on the web, they had become despondent and felt that their expensive cameras were useless for night sky work. Again, they were greatly relieved with the feeling that the problem was greatly overrated. Again, just my perspective.
    In this film, scenes at 1:18, 4:40, 4:53, and a few others, were shot with the A7SII with a Sony 28mm lens, the rest were shot with an RII using a Zeiss Batis 18mm lens. You be the judge as to whether it detracts at all from the film. Also, if it matters to you, I don’t white balance for “natural color” and this is intentional.

    https://www.youtube.com/watch?v=L71nt62ddPk

    • Ian Norman April 13, 2018 / 3:03 pm

      Hi Barry,
      I agree with you on this: it’s a problem that doesn’t present a terrible issue for images with enough star trailing. For this reason, many may be fine with it. That said, there are a few cases where it is and issue enough to be less desirable than the competition and people should at least be aware of how it affects images and any potential workarounds.

    • Barry Chall April 15, 2018 / 1:44 pm

      Hi Ian, just for a little more perspective, I’m actually glad you were key to bringing the star eater issue to light and informing your readers about it, as well as putting pressure on Sony to correct it. Also, thank you for posting the workaround fix. You performed a valuable service here. What I wanted to do in my post with the video link is put people who have, or are considering buying Sony cameras, at ease with the knowledge that, except in certain limited applications, the star eater issue isn’t as dire of a problem as some people were assuming and in many other applications, it’s not a problem at all.
      I’m planning on starting another multi-month time lapse film project next month and do plan to experiment with shooting some sequences in continous mode and others normally just to see what real world difference it will make. I’m also curious as to whether going from 14 bit to 12 bit in post will be noticable and if so, how much.

    • Marco Pigati May 17, 2018 / 6:58 am

      Hi Ian,
      I write from Italy.
      I have just bought a heavily used A7s on ebay. The firmware is 2.0.
      As far as you know, can I use the camera with the 30 seconds setting without having star eater?
      Thank you very much!
      All the best from Italy!
      Marco

  2. Matthew Richardson March 5, 2018 / 8:48 am

    There is another reason to shoot continuous when doing astrophotography on the Sony a7rII (and I presume other Sonys. I have found that when doing multiple pictures for star trails, if you are in single frame mode it takes as long to “process” the image as it does to capture the image, and you can’t take another picture while that it happening (ie. If you take a 30 Second exposure, you have to wait 30 seconds after the shutter closes for the processing to finish and to be able to take another photo). In continuous mode, you can take another picture immedity.

    • Lazar Dimitrov March 6, 2018 / 12:08 pm

      Have you disabled the “Long exposure NR” function in the settings? Sounds like you have not. What it basically does is: if exposure time is 1s or longer, the camera takes a second “dark” frame with the same exposure settings, but closed shutter. Then the camera subtracts the dark frame from the real image and stores the result in the raw file. As far as I know “Long exposure NR” is automatically disabled if shooting in continuous mode or continuous bracketing mode.

  3. Stephen February 14, 2018 / 6:21 am

    Hello, interesting topic and tks for all your efforts.
    I have an A7 and a A7r do either of the cameras have the same problems?

  4. Bryan February 11, 2018 / 1:51 pm

    What about the A7ii? No one speak about this one

    • Lazar Dimitrov March 6, 2018 / 12:10 pm

      a7ii is not affected by the star eater issue it seems (except when shooting in BULB mode).

  5. Vic February 7, 2018 / 5:55 pm

    Ian, you said you still use your A7S. Does that mean that there is a star eater workaround for it already? (eg. staying at a lower firmware, setting) Also, have you used the loxia 50 for panorama stitching on your A7S before? If so, how did you like it? Thanks for your time and keeping us updated on the star eater issue.

    • Vic February 8, 2018 / 6:38 pm

      Wow. I am sorry. I swore I read your “Open Letter” post thoroughly. Please ignore or delete my comment.

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