Building My Own Focusing Rails
I have always enjoyed photography in general but as my experience grow, I started to want to explore more specialized niches within photography. Macro photography specifically for the purpose of archiving, product photography, biological (insect and plant) photography is where I want to start exploring. Macro photography is where you get very close to your subject in order to reveal levels of detail not typically appreciable with the naked eye. The capillaries of leaves, the martian-looking surface of fungus and the furze of a spider’s abdomen are all subjects you might try to capture.
If you too are interested in this type of photography you will quickly learn that the biggest challenge with this type of photography is shallow depth of field you have when shooting at such a small scale. There are many articles that address this challenge but I think this article by B&H goes into depth discussing the topic: https://www.bhphotovideo.com/explora/photography/tips-and-solutions/the-challenge-of-depth-of-field-in-macro-or-close-up-photography
One of the methods used to get around this shallow depth of field challenge is something called focus stacking. Focus stacking is a digital image processing technique which combines multiple images taken at different focus distances to give a resulting image with a greater depth of field (DOF) than any of the individual source images. This YouTube video gives you a good understanding of the shallow depth of field and how focus stacking helps overcome it: https://www.youtube.com/watch?v=3wfI_rEGyDw
The example in the video is at an extreme magnification using microscopes to zoom in. You do not have to go to that extreme though for what I want to do. I want to start small. I want to be able to move a camera in one axes in a controlled manner. In the example in the video the microscope held the sample steady between shots so the subject didn’t move. For what I want to do it is more efficient if you lock in the focal length and simply move the camera between pictures. The challenge with this is you want to hold the camera and subject steady while moving the camera equidistant steps between pictures. Photographers use devices such as rails or racks to help them achieve this. The problem is these devices come with a pretty hefty price tag associated with them. For example this NOVOFLEX CASTEL-MICRO (https://www.novoflex.de/en/focusing-rack-castel-micro.html ) cane cost more than $5,000 once you add all the bells and whistles. The other problem I face is I currently do not have a full frame DSLR camera. I do own a Panasonic LUMIX DMC-GM1KS. I have also recently purchased a Samsung S21 Ultra that has a macro lens built into it.
For now I want to test the capabilities of the Samsung. I want to try focus stacking. I also want to keep the costs low. The article below outline how I decided to face this challenge in a cost-effective manner.
LEGO Worm Gear with Old Axle (part number 4716) Dimensions: 1.02 x 1.02 x 1.6 cm
Technic, Gear 36 Tooth Double Bevel (part number 32498)
It is important to understand I know this is not going to be as accurate as a professional rig. My tolerances are much more forgiving. I am just doing this for fun. If I enjoy this I will have justified my “want” for a more professional setup. For now though this is what I am using.
A Lego worm gear is 1.6 centimeters in length, and it takes 6 rotations to move start to finish of the gear. I have 4 worm gears mounted on an axle back-to-back so the total amount of sled travel possible is 6.4 centimeters. When I rotate the axle once the sled moves 2.64 millimeters forward or backward, depending on which way I rotate the axle. If I use the teeth on the large 36 tooth gear as marking and move one tooth at a time the sled moves 7.4 nanometers. This is more than enough accuracy for what I want to do. I will share
