Magnifying Loupe

thingiverse

The magnifying loupe empowers users to scrutinize digital camera screens or flat objects at a closer distance, thereby amplifying the image and revealing finer details. openSCAD generates STL files for various components that, when assembled with a lens, form the loupe. When used with a digital camera, it produces four pieces, whose dimensions depend on screen size, lens diameter, thickness, focal length, and bracket attachment length to the camera tripod socket. If users prefer not to attach the loupe to a camera but instead use it as a standalone magnifier, they can omit printing the bracket. For my prototype loupe, I utilized a 19x67 meniscus lens purchased from Edmund Optics. The first number represents diameter in mm, and the second denotes focal length also in mm. To achieve sharp images in corners, one should use a lens with a focal length exceeding the diagonal measurement of the screen. Lens diameter determines the field of view visible at any given time; it's beneficial to make this larger than 18mm. The second loupe version employed a 30.7x78 PCX (plano convex) lens for a 2.2 x 3 in. screen size. The larger lens and longer focal length made this model more user-friendly. This lens is currently available from Edmund Optics at a low price, part number 20518. The bracket features an adjustable slot allowing some flexibility in loupe positioning. The slot and the hole in the pyramid are sized for an 8-32 machine screw. A large hole accommodates a 1/4-20 screw to attach to the tripod socket. A middle-sized hole can be tapped for a 1/4-20 thread, enabling camera attachment to a tripod. Users should exercise caution when cutting threads in plastic; I recommend enlarging the hole with a number 7 tap drill and then carefully threading it with a 1/4-20 tap. The lens is secured within a short cylinder using a split ring. The cylinder is inserted into the pyramid's top, adjusted to achieve optimal focus. If you're experiencing difficulty focusing, begin by determining the direction of error. If focus improves when holding the loupe away from the screen, try printing a slightly longer tube. Otherwise, you'll need to change the lens focal length and reprint the pyramid. When using the loupe on printed material, it's advisable to print with translucent filament to allow ambient light in or use dark opaque materials to minimize stray light. The maker should only modify lens diameter, thickness, focal length, loupe_width1, and loupe_depth1. The rest will be automatically calculated based on user inputs. Depending on the camera tripod socket location, you might need to adjust bracketbasethickness and attachlength. To assemble the loupe, open the file in OpenSCAD, render, and save each piece while incrementing the phase variable (e.g., set phase to 1, then repeat for phases 4, 5, and 6). I designed the program this way so users only need to enter parameters once. This approach also helps prevent spider web filament connections between parts. When printing, you may need to apply tape around the cylinder holding the lens or adjust the diameter in the program based on your printer and filament specifications. Have fun and good luck!