RF 15-35mm Moiré pattern when stacking multiple night shots.

[CarmenT]

I have noticed this problem several times now with night shots taken on this lens when stacking multiple images in either StarStax of Starry Landscape Stacker (sequator). The water area gets a very weird pattern/texture in it which is not present in any of the single images. Does anyone know what could be causing this? Is it a lens or software issue? Thank you for any suggestions as to what the problem could be. 

[Peter]

Is lens correction turned on? If so, what if you turn it off?

[CarmenT]

Thank you for that thought Peter. Lens correction was turned on prior to exporting the images to be stacked  I Will try the process again without to see if it makes a difference  

[Peter]

What I thought, see the answer from John Sheehy https://www.dpreview.com/forums/thread/4685233

[kvbarkley]

Could it be reflections from the stars?

[CarmenT]

No, it is not a reflection from the stars. If you look closely in the water (especially lower right) it has a wavy pattern similar to what you would get when you take a picture of a computer screen. 

[Danny]

Thanks for joining the conversation, CarmenT!  The Community can get a clearer idea of what's going on if we knew exactly which Canon camera model you're using. That, and any other details you'd like to give will help the Community better understand your issue!

If this is a time-sensitive matter, click HERE search our knowledge base or find additional support options HERE.

Thanks and have a great day!

[CarmenT]

Thank you Danny. I am using the R6, I shoot in RAW, brand new memory card (and I have seen this when using different cards as well, so I don't think it's that), I use lightroom to edit before exporting for Starry Landscape Stacker or StarStax. 

The pattern that appears after stacking may be called "moire"? it looks like the weird patterns and waves you get when you try to take a picture of a computer screen. 

[justadude]

Assuming you are shooting RAW, not JPEG, correct?  Are you sure this isn't noticeable in any of the single images? Sometimes you have to really crank up Dehaze or Clarity to get this to show - and sometimes play with the noise reduction.  I occasionally see similar to what you have on the horizon right where the light pollution meets the darker sky.  The patterns in the water look more extreme than I have seen, but then again, this is stacked images.

[CarmenT]

Thank you Gary. Yes I shoot in RAW. I have played around with extreme edits on a single image (clarity, dehire, noise reduction, exposure, shadows, highlights etc. ) and do not get these patterns.