Electronics > Projects, Designs, and Technical Stuff
DIY Focus Stacking for Macro Photography
mawyatt:
Focus stacking in macro photography involves techniques to deal with the very shallow Depth of Focus. For example when capturing images around 5X magnification the DoF can be as shallow as 0.028mm (28 microns)! Techniques and software have been developed to capture multiple images at different focus positions, either by changing the lens focus or moving the camera/lens or subject, then "stacking" them together to render an image with much larger in focus areas.
At high magnifications moving the camera/lens is usually accomplished by a precision linear rails, either manual or motor driven. Commercial motor driven focus rails from Wemacro, Stackshot and others are very good and automated. When the desire is high resolution (high magnification) and a large Field of View, then focus stacking alone can't cover the intended area, so a type of stacking that involves a macro "Panorama" of multiple stacking images is required, often called Stack and Stitch, or S&S. There isn't any inexpensive available commercial equipment for S&S, so this opportunity begs for the DIY approach. Also if one wants to venture beyond what the standard commercial focus rails offer in performance, a DIY approach become attractive.
Photomacrography is a great site for those interesting in macro photography, including DIY type efforts from custom developed lens to complete rig setups.
https://www.photomacrography.net/forum/
Here's a few examples that I've been involved with.
Some videos.
https://www.photomacrography.net/forum/viewtopic.php?t=39392&highlight=
https://www.photomacrography.net/forum/viewtopic.php?t=39396&highlight=
Custom developed S&S system based around Raspberry Pi Development.
https://www.photomacrography.net/forum/viewtopic.php?t=38511&highlight=
https://www.photomacrography.net/forum/viewtopic.php?t=38548&highlight=
https://www.photomacrography.net/forum/viewtopic.php?t=38604&highlight=
https://www.photomacrography.net/forum/viewtopic.php?t=38512&highlight=
https://www.photomacrography.net/forum/viewtopic.php?t=39318&highlight=
https://www.photomacrography.net/forum/viewtopic.php?t=39428&highlight=
https://www.photomacrography.net/forum/viewtopic.php?t=39755&highlight=
Stepper Motor Controller Development.
https://www.photomacrography.net/forum/viewtopic.php?t=39473&highlight=
https://www.photomacrography.net/forum/viewtopic.php?t=39689&highlight=
https://www.photomacrography.net/forum/viewtopic.php?t=39428&highlight=
https://www.photomacrography.net/forum/viewtopic.php?t=39756&highlight=
Piezo Electric Stage Development.
https://www.photomacrography.net/forum/viewtopic.php?t=40679&highlight=
https://www.photomacrography.net/forum/viewtopic.php?t=40681&highlight=
https://www.photomacrography.net/forum/viewtopic.php?t=40682&highlight=
https://www.photomacrography.net/forum/viewtopic.php?t=40510&highlight=
LED Strobe Light Development.
https://www.photomacrography.net/forum/viewtopic.php?t=40999&highlight=
https://www.photomacrography.net/forum/viewtopic.php?t=41353&highlight=
https://www.photomacrography.net/forum/viewtopic.php?t=41464&highlight=
Chip image source for some older renderings, latest results are still proprietary. Download images for full resolution, the last image is a sliver (cracked off during attempted wafer split) of a very old abused wafer that was a test image for the Fully Automated S&S System mentioned, its ~29,000 by 22,000 pixels.
http://img.gg/taIZ99M
Few older examples.
Hopefully some folks will find this interesting.
Best,
Mike
RoGeorge:
An older focus stacking related idea of mine, that I will probably never pursue, so just dropping it here:
- use an electrically controlled focus lens (based on electrowetting, so the focus adjusting to be faster than for a mechanically controlled focus), either DYI (https://youtu.be/tOEyxavTiGw) or ready made (https://www.corning.com/worldwide/en/innovation/corning-emerging-innovations/corning-varioptic-lenses.html). If the adjustable lens is not fast, maybe using a mechanically vibrated ocular.
- high speed camera taking snapshots while the focus plane is changed with the controlled lens
- FPGA implementing a live focus stacking algorithm
Shortly said, an automated focus stacking camera/microscope. The result should be a live image (movie) with increased depth of field.
In cases where direct eye observation is required (optically), a fast LCD screen can be put in the optical path of the microscope, to dim out those pixels identified by the stacking algorithm as out of focus. The LCD will have only an on/off level for each pixel (each pixel driven by the focus stacking algorithm), so the eye could integrate over time only the sharp pixels for each focal plane. 8)
DrG:
This is news to me and thanks. It sounds like HDR but for focus. Instead of stacking different exposures, which are easy to shoot using bracketing, the same idea is done with focus? That is making my head hurt :)
Bookmarked this thread and that site -
SilverSolder:
You can do focus stacks with your normal SLR (or at least variable focus!) camera by taking several pictures (min 2 of course), loading them into Photoshop, and run the Photomerge function. Easy as! :D
Of course, things get harder and harder the shallower the depth of field. The mechanics of holding the camera becomes the main problem at some point.
DrG:
--- Quote from: SilverSolder on June 30, 2020, 12:13:19 am ---
You can do focus stacks with your normal SLR (or at least variable focus!) camera by taking several pictures (min 2 of course), loading them into Photoshop, and run the Photomerge function. Easy as! :D
Of course, things get harder and harder the shallower the depth of field. The mechanics of holding the camera becomes the main problem at some point.
--- End quote ---
By bracketing f-stop? or am I just not getting it?
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