Converting A Sigma Lens To Canon, Digital Functionality Included

July 1, 2022 by Lewin Day 9 Comments

These days, camera lenses aren’t just simple bits of glass in sliding metal or plastic housings. They’ve often got a whole bunch of electronics built in as well. [Dan K] had just such a lens from Sigma, but wanted to get it working fully with a camera using the Canon EF lens fitting. Hacking ensued.

The lens in question was a Sigma 15-30mm f/3.5-4.5 EX DG, built to work with a Sigma camera using the SA mount. As it turns out, the SA mount is actually based on the Canon EF mount, using the same communications methods and having a similar contact block. However, it uses a mechanically different mounting bayonet, making the two incompatible.

[Dan] sourced a damaged EF lens to provide its mount, and modified it on a lathe to suit the Sigma lens. A short length of ribbon cable was then used to connect the lens’s PCB to the EF mount’s contacts. When carefully put back together, the lens worked perfectly, with functional auto-focus and all.

It goes to show that a little research can reveal possibilities for hacking that we might otherwise have missed. [Dan] was able to get his lens up and running on a new camera, and has taken many wonderful pictures with it since.

We’ve seen some great lens hacks over the years, from 3D printed adapters to anamorphic adapters that create beautiful results. If you’ve got your own mad camera hacks brewing up, drop us a line!

Lenses: From Fire Starters To Smart Phones And VR

June 28, 2022 by Matthew Carlson 21 Comments

In antiquity, we see examples of magnifying crystals formed into a biconvex shape as early as the 7th century BC. Whether the people of that period used them either for fire-starting purposes or vision is unclear. Still, it is famously said that Emperor Nero of Rome watched gladiator games through an emerald.

Needless to say, the views we get through modern lenses are a lot more realistic. So how did we get from simple magnifying systems to the complex lens systems we see today? We start with a quick journey through the history of the camera and the lens, and we’ll end up with the cutting edge in lens design for smartphone cameras and VR headsets.

Continue reading “Lenses: From Fire Starters To Smart Phones And VR” →

DIY Night Vision, Where Four Is Better Than Two

June 26, 2022 by Donald Papp 23 Comments

Night vision projects are great, and the hardware available to hobbyists just gets better and better. [Just Call Me Koko] shows off just such a build using four low-light, IR-sensitive cameras, four displays, and four lenses in 3D printed enclosures mounted to a helmet. Why four? Well, mounting two cameras and displays per eye is the easiest way to yield a wider field of view, and for bonus points, it sure looks extra weird.

At its heart, each of the four segments is the same. A Foxeer Night Cat 3 camera is mounted at the front, its output is connected directly to a 2″ diagonal NTSC/PAL display, and at the rear is a DCX (double convex) lens 38 mm in diameter with a 50 mm focal length. Add a printed enclosure, and the result is a monocular night vision display. Do it three more times and arrange them around one’s eyeballs, and one can make a night vision system with a panoramic view that probably takes only a little getting used to.

How well does it work? [Just Call Me Koko] does some walking around and also tries some target practice while wearing them, and concludes that while they don’t have nearly the clarity of the real deal (the 320×240 resolution displays limit the details one can perceive), they do work fairly well for what they are. Also, the cost of parts is a small fraction of the cost of the real thing, making it a pretty enjoyable project in the end.

The kind of hardware available to hobbyists today is what makes this kind of night vision project accessible, but there’s always the good old high-voltage analog method.

Continue reading “DIY Night Vision, Where Four Is Better Than Two” →

Recreating A Camera Shot

June 14, 2022 by Matthew Carlson 14 Comments

People rolling off shields and spears clashing against swords as the camera zooms in and out wildly makes the hallmark action sequences in the movie 300 so iconic. Unfortunately, achieving this effect wasn’t particularly easy. Three cameras were rolling, each with a different lens (100mm, 50mm, and 21mm) to capture a different view of the same scene. In post-production, you can dramatically switch between the three cameras since the shot is synchronized. The folks over at [Corridor Crew] wanted to recreate the effect, but rather than create a custom mount to hold three expensive cameras, they 3d printed a custom mount to hold three costly smartphones.

While there are three cameras on the back of most phones, most phones can’t shoot in slo-mo from all cameras simultaneously. So they would need a rig to hold three phones. The first design was simple and just brackets to hold phones. While nice and sturdy, getting the phones in or out wasn’t easy, and getting to the record button was tricky. iPhones have this handy little magnetic ring on the back. They had a bracket that worked pretty well after a few iterations on the design and some printer issues. Since each camera has optical image stabilization, it is easy for the lenses to get out of alignment, which can mar the shot. However, they somewhat covered up the effect in post. With a working prototype, the only thing left to do was to slice a bunch of piñatas in slow motion with a thrumming soundtrack.

We love seeing exciting camera setups and iterating to find something that works. This dual-camera setup has a very different goal and tries to lean into the parallax effect rather than hide it. Video after the break.
Continue reading “Recreating A Camera Shot” →

Gaming Mouse Becomes Digital Camera

May 16, 2022 by Bryan Cockfield 15 Comments

Ever since the world decided to transition from mechanical ball mice to optical mice, we have been blessed with computer pointing devices that don’t need regular cleaning and have much better performance than their ancestors. They do this by using what is essentially a tiny digital camera to monitor changes in motion. As we’ve seen before, it is possible to convert this mechanism into an actual camera, but until now we haven’t seen something like this on a high-performance mouse designed for FPS gaming.

For this project [Ankit] is disassembling the Logitech G402, a popular gaming mouse with up to 4000 dpi. Normally this is processed internally in the mouse to translate movement into cursor motion, but this mouse conveniently has a familiar STM32 processor with an SPI interface already broken out on the PCB that could be quickly connected to in order to gather image data. [Ankit] created a custom USB vendor-specific endpoint and wrote a Linux kernel module to parse the data into a custom GUI program that can display the image captured by the mouse sensor on-screen.

It’s probably best to not attempt this project if you plan to re-use the mouse, as the custom firmware appears to render the mouse useless as an actual mouse. But as a proof-of-concept project this high-performance mouse does work fairly well as a camera, albeit with a very low resolution by modern digital camera standards. It is much improved on older mouse-camera builds we’ve seen, though, thanks to the high performance sensors in gaming mice.

Making A Concrete Pinhole Camera

May 12, 2022 by Lewin Day 9 Comments

A pinhole camera is a simple device that can be built out of virtually any simple closed chamber, and is a great way to learn about the basic principles of photography. [amuu] has created a version that can be readily made out of concrete, of all materials!

The photos captured by the camera featured some artifacts from light leaks and grit, but the results are enjoyable for their lo-fi, homebrew aesthetic!

The build starts with the creation of a mold for the concrete, using laminated sheets of foam. The foam is assembled with cut-up pieces of a ballpoint pen serving as cores in the mold. This provides a space for the film winders in the final product. The concrete is then mixed and poured into the mold, and allowed to set. Tapping or vibrating the mold is key to getting all the air bubbles out of the mixture.

Once set, the foam is mechanically removed from the concrete and the camera can be finished off. The internals are given a lick of black paint to improve the camera’s light-tightness. The shutter, pinhole, and film winder are then also fitted to allow the camera to function.

[amuu]’s first attempt to take photos with the camera lead to some results that were pleasingly lo-fi. There are overscan issues on the film and some other artifacts, but overall, the results are esoteric and fun. If you’re not a fan of the concrete camera, though, you can always consider making a 3D-printed pinhole camera instead!

Learn Sign Language Using Machine Vision

April 30, 2022 by Bryan Cockfield 9 Comments

Learning a new language is a great way to exercise the mind and learn about different cultures, and it’s great to have a native speaker around to improve the learning experience. Without one it’s still possible to learn via videos, books, and software though. The task does get much more complicated when trying to learn a language that isn’t spoken, though, like American Sign Language. This project allows users to learn the ASL alphabet with the help of computer vision and some machine learning algorithms.

The build uses a computer vision model in MobileNetV2 which is trained for each sign in the ASL alphabet. A sign is shown to the user on a screen, and the user needs to demonstrate the sign to the computer in order to progress. To do this, OpenCV running on a Raspberry Pi with a PiCamera is used to analyze the frames of the user in real-time. The user is shown pictures of the correct sign, and is rewarded when the correct sign is made.

While this only works for alphabet signs in ASL currently, the team at the University of Glasgow that built this project is planning on expanding it to include other signs as well. We have seen other machines built to teach ASL in the past, like this one which relies on a specialized glove rather than computer vision.

Continue reading “Learn Sign Language Using Machine Vision” →