Microscope and photo stacking

Introduction

Create a microscope with good magnification and automatically adjustable specimen board. Take automatically photos at different heights of the specimen board. Stack the photos using some methods.

https://web.archive.org/web/20160917212243/http://photoblog.edu-perez.com/2009/01/greater-depth-field-macro.html

Theory

We use Raspberry Pi 4 or Zero with 12 MP camera. The camera supports C and CS mount lenses (CGL 6 mm CS-mount and 16 mm C-mount lenses). Also M/CS mount adapter is available.

Screen

The small screen is a 3.5 inches TFT LCD capacitive touchscreen with a 480×320 resolution that supports up to 1920×1080. It is connected to the Raspberry Pi with a HDMI adapter for display, and to the GPIO port for the touchscreen function.

Lenses and Magnification

HQ camera, lens, extension tube. 50mm C mount lens. The larger the extension ring, the shorter the depth of field.

The ocular is a magnifier meant to look at the intermediate image formed by the objective lens. Eye looks into eyepiece, thus it should produce a virtual image at infinity (the eye is relaxed). The object plane of the ocular is the image plane of object.

Total magnification: $M=M_{\text{objective}}\times M_{\text{ocular}}$ .

Aim: Wide magnification range: Samples with features from several centimeters to several micrometers can be imaged without changing the objective lens.

Particles with diameters between 1um and 10um. https://publiclab.org/notes/partsandcrafts/02-15-2018/2-attaching-your-raspberry-pi-camera-to-a-microscope-objective-lens

Microscope lenses: RMS Threaded stands for Royal Microscopy Society.

https://www.seeedstudio.com/Microscope-Camera-300X-C-Mount-Lens-for-Raspberry-Pi-High-Quality-Camera-p-4627.html

https://www.amscope.com/accessories/objective/100x-oil-achromatic-microscope-objective-for-compound-microscopes.html

https://www.nikonpassion.com/la-macrophotographie-guide-pratique-le-rapport-de-grandissement/

https://www.cambridgeincolour.com/tutorials/macro-lenses.htm