Using Focus-Stacking To Study Die Varieties In 3d

I thought I'd post one more example of focus-stacking. This time, I have imaged a small area on a coin--a dramatic overdate on this Peru 1/2 Dinero: 1903/1893.
This time, I wanted to see how finely I could resolve the relief of the date, to see how this might translate as a 3D simulation for study.

Here's focus-stacked image of the date area--the FOV is just 3mm! This is at 100% crop with no sharpening in camera or in software.



When the image is stacked, Helicon Focus generates a depth map. Compared to my previous depth map I posted, you can see this one is much more detailed.
I accomplished this by using the smallest focus increment I could make (hand-held). When I use tethering software to do this, the resolution should improve further.

This depth map is the result of 21 focus increments. Even with a small FOV (3mm), it's picking up the texture of the fields!



Using this data, Helicon Focus quickly created a video of the 3D simulation. I played around with the settings to produce a strong sense of relief, such as setting the "relief amplifier" to 74, and increasing the side-to-side rotation. The result is a pretty interesting animation--fun stuff! While the final HD output is a nicely optimized 6.5mb file, Youtube went ahead and compressed it further.

View full-screen here.


You can see some areas have better resolved relief, such as the top and sides of the date.
The bottom relief suffers because the camera angle could not pick up the subtleties at the base of the digits.