I've been seeing (and reading) more and more articles touting the use of Smart Objects as an effective way to stack images and reduce noise. So, I decided to test it the best way I know how - pitting RegiStax 18.104.22.168 versus Photoshop's Smart Object blending.
The Test: 40 images of the moon. A waning gibbous moon taken on March 15th, 2017 in clear early morning sky taken with the Nikon D750 mounted on a tripod with the Tamron SP 150-600mm f/5-6.3 Di VC USD. Utilizing the same forty images, I've processed them both through a RegiStax process and a Photoshop process.
The Hypothesis: Be able to process images utilizing only one major editing program (Photoshop) and get a premium image quality.
Step 1: Import the images into Adobe Lightroom. Starting with one image, Crop the image to the desired size - it is necessary to crop in from 600mm for Adobe Photoshop to have enough data to be able to align the images later. Adjust Exposure, Saturation, Contrast (+50), and Clarity (+40) to the preferred levels. Remove any Chromatic Aberration. Now, Copy Setting... and Paste Settings in the gallery view to the remaining images. Before exporting the images, you may need to go back in and individually center the crops depending on how much the moon drifted while shooting. Now, select all the images, and go to Photo...Edit In...Open as Layers in Photoshop.
Step 2: Alignment - Once your layers load into Photoshop, select all the layers and use Edit...Auto-Align Layers. Photoshop does a very good good a overall alignment, and I use this method no matter how I process the images. Now here is where the test diverges.
Photoshop Test: While the layers are all selected. Select Layers...Smart Objects...Convert to Smart Objects (and wait....) Next under Smart Objects select Stack Mode...Median. Save your file and finish sharpening as desired in Photoshop or Lightroom. For this test, I did increase the Sharpening in Lightroom while applying a generous Masking.
RegiStax: In Photoshop select Export - Layers to File, saving your files to a new folder on your hard drive. Load and process in RegiStax as you normally would. Since RegiStax is complicated, in a future blog post I'll cover a step-by-step 'How To' for RegiStax image stacking. For right now you can reference the tutorial on RegiStax website here.
Below are two sets of samples (RegiStax 22.214.171.124, Photoshop Smart Object Mean mode, and best single frame.)
As you can see in the images above, unfortunately the hypothesis was wrong. The images coming out of RegiStax 6 are clearly more detailed and more crisp. While Photoshop does a great job of eliminating noise, personally I prefer the RegiStax images.
Let me know your thoughts or questions.