If you want to take a long exposure photograph, you need a tripod to hold your camera steady. But a tripod won’t help when the ground it’s standing on is moving. That’s exactly the problem [Emvilza] ran into when he wanted to take minutes or hours long photographs of the night sky. His solution was to build a barn door tracker, which he carefully documented in both English and Spanish.
Barn door trackers, also known as scotch mounts have been used by photographers for many years to cancel out the rotation of the earth. This causes stars to appear frozen in the sky and allows for photographs of very dim celestial objects. These trackers range from simple hand-cranked affairs to complex mechanical creations. [Emvilza] decided to have a go at designing and building his own tracker, using only basic tools, as he didn’t have access to a CNC or 3D printer.
The tracker itself is built from wood, with metal hardware. [Emvilza] spent a ton of time designing the tracker using SketchUp. The carefully drawn plans ensured everything would fit together and operate correctly.
One of the toughest parts was accurately bending a threaded rod enough to make it work with the tracker, but not bind the drive system. The mount’s motion comes from a threaded rod. The rod is driven by a stepper motor. Control and sensing is handled by an ATmega328 programmed using the Arduino toolchain. [Emvilza] learned Eagle and designed a PCB. Rather than etch a board, he simply built the circuit on perfboard, following his layout and traces.
The end result is a tracker that looks and performs great — just check out the images on [Emvilza’s] site to see some examples. Not only that, [Emvilza’s] well written documentation will help anyone looking to build a tracker in the future!
As smartphone cameras improve with each new generation, making quality video content is getting easier all the time. This means it takes a little more to stand out, so it pays to get creative with your cinematography. A slider is a great way to get some different shots, and you can build one pretty cheaply too (Youtube link, embedded below).
For smooth motion, [Nikodem Bartnik] used aluminium extrusion for the rails, along with some roller bearing wheels designed to suit. The wheels are built into a 3D printed carriage, which is also fitted with a spherical clamping camera mount. It’s all wrapped up with some socket head cap screws and 3D printed brackets to tie it all together.
Dimensional accuracy is key to the smooth operation of a slider, so you’ll want to have your printer set up well if you’re going to attempt this one. [Nikodem] demonstrates the slider is capable of taking the weight of an mid-range SLR with a tastefully sized lens, but if you’re going for something telephoto, you might want to go for something bigger. You could also consider a motorized rig instead. Video after the break.
Photographic slides were popular in the middle part of the 20th century, but are long forgotten now. If you’ve found a handful in a dusty attic, you might consider sending them away to be digitized professionally, or using a flatbed scanner at home. [Bryan Howard] found himself with over 200,000 slides, however, so that just wouldn’t do. Instead, he endeavored to build an automated scanner of his own.
Like many similar projects, [Bryan] started with an existing slide projector as a base. This means that all the difficult work of slide transport is already taken care of. The projector has then been upgraded with an LED light source and other tweaks befitting its new role. An Arduino Pro Micro runs the show, firing off the camera to image each slide before loading the next one into place. The DSLR responsible for imaging is then hooked up to a PC so the incoming images can be checked while the machine is in operation.
Preliminary tests are promising, with the scanner successfully capturing several slides in a row. [Bryan] estimates that, with a capture time of between 1 and 2 seconds per slide, it should take somewhere between 2-5 days to image the entire collection.
Blowing bubbles is a pastime enjoyed by young and old alike. The pleasant motion and swirling colors of the bubbles can be remarkably relaxing. With the right tools and techniques, it’s possible to take striking photos of these soap film phenomena, and that’s exactly what [Eric] and [Travis] did.
After beginning with a robotic arm and a computer fan blowing bubbles, the project moved towards a simple stepper motor setup. A thin frame is lowered into a solution of soapy water, then brought back up by the stepper motor. The resulting soap film is held in front of a black background and carefully lit with a softbox light.
Lens selection is critical for this sort of work – in this case, a TS-E 50mm Macro f/2.8 lens was the order of the day. [Eric] shares other tips for taking great shots, such as adding sugar to the solution to make the soap film last longer, and using a modified speaker to help “paint” the surface of the films.
The resulting images are beautiful examples of the art, showing vibrant colors from the interference patterns created by the light. [Eric] has done a great job of clearly documenting the development process and the final results, making it possible for others to recreate the project elsewhere.
In its most basic sense, photogrammetry refers to taking measurements from photographs. In the sense being discussed here, it more precisely refers to the method of creating a 3D model from a series of photographs of a physical object. By taking appropriate images of an object, and feeding them through the right software, it’s possible to create a digital representation of the object without requiring any special hardware other than a camera.
[Eric] shares several tips and tricks for getting good results. Surface preparation is key, with the aim being to create a flat finish to avoid reflections causing problems. A grey primer is first sprayed on the object, followed by a dusting of black spots, which helps the software identify the object’s contours. Camera settings are also important, with wide apertures used to create a shallow depth-of-field that helps the object stand out from the background.
With the proper object preparation and camera technique taken care of, the hard work is done. All that’s then required is to feed the photos through the relevant software. [Eric] favors Agisoft Metashape, though there are a variety of packages that offer this functionality.
The Instax SQ6 and Fujifilm’s entire range of instant cameras are fun little boxes that produce instant photos. It’s a polaroid that’s not Polaroid, and like most instant cameras, the lenses are just one or two pieces of plastic. A lens transplant is in order, and that’s exactly what [Kevin] did to his Instax camera.
The key to this lens transplant project is to make it not look like a complete hack job. For this, [Kevin] is keeping the number of custom mechanical parts to a minimum, with just two pieces. There’s a lens shroud that screws down to the current flange on the camera’s plastic chassis, and should blend in perfectly with the rest of the camera. This demanded a significant amount of 3D modeling to get perfect. The other mechanical part is just a plastic disc with a hole in it. These parts were ordered from Shapeways and bolted to the camera with only a few problems regarding spacing and clearances. This didn’t prevent the camera from coming back together, which is when the documentation becomes fast and loose. Who could blame him: the idea of putting real lenses on an instant camera is something few can resist, and the pictures that come out of this modified camera look great.
The current state of the project with a single lens leads the camera to have an inaccurate and tunnel-like viewfinder, but a huge modification brings this project into twin-lens reflex territory. There are more modifications than camera here, but all the printed parts are documented, there are part numbers for McMaster-Carr, and the camera has full control over focusing and framing.
If you need help visualizing magnetic fields, these slow-motion video captures should educate or captivate you. Flux lines are difficult to describe in words, because magnet shape and strength play a part. It might thus be difficult to visualize what is happening with a conical magnet, for a person used to a bar magnet. We should advise you before you watch the video below the break, if you are repelled by the sight of magnetite sand clogging a bare magnet then flying on the floor, this is your only warning.
The technique and equipment are simple and shown in the video. A layer of black sand is spread on a piece of tense plastic to make something like a dirty trampoline, and a neodymium magnet is dropped in the middle. The bouncing action launches the sand and magnet simultaneously so they are hanging in the air and the particles can move with little more than air resistance.
These videos were all taken with a single camera and a single magnet. Multiple cameras would yield 3D visuals, and the intertwining fields of multiple magnets can be beautiful. Perhaps a helix of spherical magnets? What do you have lying around the hosue? In a twist, we can use magnets to simulate gas atoms and trick them into performing unusual feats.