Storm's comments on stacking software and post processing

For stacking software, I started with Zerene Stacker. It is very easy to use and I especially like the retouching / editing features. However, the guy that made Zerene, doesn’t do many updates or changes. The product has not evolved and it takes an eternity (1 or 2 hours) to stack one photo that has in the range of 100+ frames. I cut over to Helicon Focus a few months ago and I am not going back. It is so much faster and the developers have really improved it since the first time I looked at it.

You have to get a feel for how many frames to shoot given a certain magnification. There is no cut and dried calculation when using a bellows. For the 10x Mitutoyo objective, with the bellow fully collapsed, I am shooting intervals of 0.007mm. With the bellows fully extended, I typically use 0.004mm stepping intervals. The Stackshot photo rail is capable of this resolution. It’s just something you have to play with. Depending on the depth of the shot, a stack is typically composed of 100 – 200 frames.

I am using a Stackshot photo rail. I have increased the settling time between rail movement and snapping the photo from the default setting it came with. I allow about 5 seconds of vibration settling time after the Stackshot carriage moves before taking the shot with my horizontal setup. I have experimented and increasing the dwell time past this had no additional benefit.

In his presentation at NCMA on micromineral photography, Bruce Kelley, who employs a vertical setup remarked that he was allowing several minutes of settling time between shots. He does take sharp pictures, but that is a long time. Bruce employs flash. He built his own stacking rail using an Arduino controller.

I process the frames all at the same time with Adobe Lightroom. Then I export to Helicon Focus for the stacking. Finally, I take the final TIFF image and crop it and perhaps touch up some spots, using Adobe Photoshop.

Their program (Helicon) works well. It has saved me hours of time. In addition, once you get used to it, the retouching features in Helicon Focus are much more powerful than Zerene Stacker. Similar to Zerene, there are multiple rendering modes. Where Zerene has two modes of rendering: Depth Map (DMAP), and Pyramid (PMAP), Helicon Focus has 3 rendering modes: Weighted Average, Depth Map, and Pyramid. In most cases, I use Pyramid mode (the least smoothing) which provides the sharpest image.

Helicon Focus has a fast render/ preview mode that allows you to tweak various settings and quickly see a low-resolution render. When you have the controls tweaked the way you want and/or you have deleted images bad images from the stack, you press the Render button to get a high-resolution render. Helicon Focus typically returns a full render in just a few minutes. It is dependent somewhat on computer power.

Helicon has a habit of leaving temp files on the hard drive during processing. I have to go in every once in a while and manually delete these unused Temp files. Also, I delete the original stack photos once I am satisfied with the rendered image.