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

18 Responses

  1. David Pan January 17, 2018 / 4:32 am

    Thank you Ian, for letting us all know about this !

    • David Pan January 17, 2018 / 4:36 am

      If this setting drops RAW files to 12-bit, what is it usually ?

    • Ian Norman January 17, 2018 / 9:02 am

      It’s usually 14-bit.

  2. Ron West January 16, 2018 / 10:11 pm

    Well, I sold my a7R II based on lonely speck’s identification of the star-eating problem. Sony had taken a long time to respond and it appears they have remained silent ever since. I have had many disappointments with Sony’s nonchalance in ignoring all my emails.

    I’ve taken a huge loss in selling my Sony a7R II and lenses, I’ve decided no matter how much they improve their cameras and lenses in the full frame market or any other electronic market I will no longer be purchasing anything that has a Sony label.

    I’ve now moved to the 4/3rds platform with the Olympus OMD-E M1 Mark II and the m.Zuiko PRO lenses. I’ve yet to find out if my 9.25 inch Celestron CGE can take the Olympus M1 with an adapter.

  3. Ron Barnell January 16, 2018 / 7:51 pm

    With the impending release of the A7SIII ( CP+ – Camera & Photo Imaging Show /March ? ) , I would have to say – that they need to have fixed this once and for all – without any menu-manipulation, etc.

  4. Diego R January 16, 2018 / 2:11 pm

    As if we didn’t already have too many things to worry about (cloud coverage, remote locations, moon phase, galactic center position), now you can’t shoot in bulb mode, and have to wait for Sony to get their act together and issue a fix…

    Screw Sony man…

  5. Walter Smolenski January 14, 2018 / 5:38 pm

    This guy is doing some amazing asltrophotograpy with the a7RIII and says that the problem is there but to small to influence the images. take a look at his galaxy and nebula photos.

  6. PrawnyPants January 12, 2018 / 9:03 pm

    I’d be curious to know about the A7rIII, as well. I have one along with the 16-35mm 2.8 GM. What say you, fellas? I think one of us needs to step up to the plate and take some sample images. I’d go out tonight and do it myself if I weren’t suffering from the flu from hell and if it weren’t -28C outside tonight.

  7. Walter Smolenski January 12, 2018 / 2:04 pm

    So you say that the A7RIII is still not working? I saw an article that suggested that it was fixed. Do you have a link to tests that that show it is still needing fixing. I was almost out the door to go to the camera shop to get it and the Zeiss 18mm 2.8. here is the link

  8. Mark Compton January 11, 2018 / 1:58 pm

    Thanks a lot for this insightful analysis. I’ve just set up my Sony NEX-6 for AP and was about to do my first shots (as soon as the clouds clear). Should I anticipate the same problems with it?

    • Ian Norman January 17, 2018 / 8:56 am

      The NEX-6 is a different generation of camera and may not have the same issue. I have not personally tested it.

  9. Chris January 11, 2018 / 10:33 am

    What this tells me is that there is no reason why Sony can’t implement an off switch for this spatial filtering.

  10. Neal January 11, 2018 / 5:23 am

    Would this also work in the ‘Self-timer (Cont.): 2 sec. 5 img.’ mode? That is my preferred astro mode as It will take all 5 shots with an equal amount of time between them. Then I can stack them all later.

    • Ian Norman January 12, 2018 / 11:16 am

      Hi Neal, I’m not sure actually as I did not get any frame from the self-timer modes.

  11. Hal Mitzenmacher January 10, 2018 / 3:46 pm

    Hi Ian,

    Thanks for the heads up on this work around for the star eater issue on the A7rii. Although you state “There isn’t a single reason to enable continuous shutter mode for astrophotography since our shutter times tend to be very very long”, I have found that for stacking Milky Way images for SLS, setting my A7Rii to 8-10 second exposures in continuous mode is an easy way to capture the 8-16 exposures I need for stacking. From what you have indicated in this post, I apparently been mitigating the star eater issue, without even knowing I was doing so! Thanks for the info.

    • Ian Norman January 12, 2018 / 11:15 am

      I suppose that does make sense if you have a remote to hold the shutter button down!

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