Removing Coma Aberration in Adobe Photoshop: Astrophotography Tutorial

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In this video tutorial, Tyler Sichelski walks through a novel method for removing coma aberration from astrophotography using Adobe Photoshop.

Introduction

We’re always on the look out for lenses that have low levels of aberration (read about the different types of aberration in our practical guide to lens aberrations). But sometimes it’s impractical to just ditch your current gear and upgrade to something that’s only slightly sharper. Tyler Sichelski put together a short and simple video tutorial of how he uses Adobe Photoshop to remove coma aberration from the stars in his astrophotography.
Check out the video below:

If you’d like to follow along with Tyler in the tutorial, he has shared his unedited full resolution photograph with us. Download the full resolution 8.6MB jpeg here.

Before and After

Tyler used his Canon EOS 6D and Tokina 16-28mm f/2.8 lens to shoot this photograph of the Galactic Center rising above the rocks of Sedona, Arizona. The Tokina 16-28mm f/2.8 lens is a great choice for an affordable ultra wide angle full-frame lens but it’s not absolutely perfect when shooting at f/2.8 and shows some mild coma and astigmatism in the corners of the image. Check out this before and after to see how Tyler’s method reduces the apparent aberration in the image and gives the stars a slightly sharper look:

Conclusion

Coma aberration can be a bothersome element in astrophotography. It distorts the shape of the stars and that can distract from the desired look of the final image. Tyler’s simple method is like a “blemish” removal technique for astrophotos that improves the apparent sharpness of the image.

The most beneficial aspect of Tyler’s coma aberration removal technique is that it allows us to continue to use our lenses at their lowest f/number, in spite of what aberrations might start to show up. The lower the f/number, the more light the camera can collect and the “cleaner” the image will typically appear but lenses usually have show worse aberration performance at the lowest f/numbers. Having the option to correct for apparent aberrations in post processing ends up becoming a useful tool for the times when we prefer to use a lower f/number at the expense of aberrations.

Equipment

We personally buy almost all of our equipment through Amazon and B&H. Each are some of the most reputable online retailers, they both have an excellent return policy and are guaranteed to have the lowest prices anywhere online. If you are considering buying any equipment, consider buying through the affiliate links on this page. You won’t pay anything extra, but Tyler Sichelski will receive a small commission (usually 2-4%) which helps him keep contributing to Lonely Speck. Here are links to some of the gear that Tyler used for this particular tutorial:

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Thanks so much for being a part of our astrophotography adventure.

-Ian

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Ian Norman

Creator at Lonely Speck
Ian Norman, co-founder and creator of The Photon Collective and Lonely Speck. Ian is a full time traveler, photographer and entrepreneur. In February 2013, he called it quits on his 9-to-5 to pursue a lifestyle of photography. Follow Ian's photography adventures on Instagram.

10 Responses

  1. Joshua April 11, 2016 / 7:16 pm

    Great work Tyler and thank you for making the video available! I am new to photo shop and was able to follow along and fix some coma issues in a photo of mine and will continue with future images.

    Enjoy the shoot,

    Josh

  2. David March 22, 2016 / 1:29 pm

    Fantastic tutorial. As it pertains to workflow, I’m interested to hear more about where you go following the COMA correction… Based on the start of this tutorial, this work should be done prior to any other changes (“pre-processing correction”). As such, I’m moving from LR > PS. Once I manage my COMA modifications, I wonder what you’d recommend as to making additional edits? Since I prefer to work in LR, what file would you recommend that I save this in with PS before moving back to LR?

    Thanks!

  3. Stan Green March 9, 2016 / 7:59 am

    I too have that Tokina lens and, yes there is coma, but it is great for general photography. Since I live on the East Coast (lots of light pollution and high humidity) I do not have the opportunity to shoot that many starscapes. As a result the thought of buying a dedicated lens (Rokinon) for star photos does sit well with my psych. Found your tutorial fascinating and I began to start/stop the video in order to capture your instructions but I was becoming confused. Bottom line, have you prepared a set of written instructions, that I could use as I follow your video?

  4. William January 21, 2016 / 1:38 pm

    You guys are simply brilliant! Useful insights, professionally presented, perfectly paced… I am appreciating all you are doing here and it has greatly helped my images.

  5. Tim Leach December 29, 2015 / 6:22 am

    Tyler-

    Awesome tutorial. Such an easy fix to a common problem.

  6. Tyler Sichelski December 8, 2015 / 7:29 pm

    Thank you for the comment! I hope you find it useful.

  7. Randy December 2, 2015 / 5:55 pm

    Thanks for the info. I am new at astrophotography. and this is great. My son is getting a new Canon for x-mas, and we are learning together!
    Thank you Ian.

  8. Joolz December 2, 2015 / 3:33 pm

    Thanks for this tutorial! Didn’t know there was an option for fixing coma.

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