If you’re in the market for a telephoto lens, the available range of optics for your camera is limited only by the size of your bank account. So when [Pixels and Prisms] promises a telephoto for $13 USD it has to be worth a second look, right? Where’s the catch.
The lens has a 3D printed shell containing the optics, with associated focusing and aperture, and has a mount designed for Canon cameras to give a result with 163 mm focal length and f/2.5 . When a Canon lens costs many times more it’s evident that there is some compromise involved, and it comes in the lens system being very simple and comprised of off-the-shelf surplus lenses without the great effort put in by the manufacturer to correct distortion. The result is nonetheless a very creditable lens even if not the first choice for a paparazzo in pursuit of an errant politician.
The real interest for us in this open source project comes in it being something of an experimenter’s test bed for lenses. There’s no need to use the combination shown and the design can be readily adapted for other lenses, so spinning one’s own lens system becomes a real possibility. Plus it’s achieved the all-too-easy task of engaging a Hackaday writer’s time browsing the stock of the Surplus Shed.
We’ve featured a lot of lens projects over the years, but they more often take an existing camera lens as a starting point.
So you want to photograph Eclipse 2017 but you don’t want to rush out and buy an expensive DSLR just for the event? Not a problem, if you build this simple smartphone filter and occluder.
It all started innocently enough for [Paul Bryson] with his iPhone and a lens from those cheap cardboard eclipse glasses we’re starting to see everywhere. Thinking that just taping the filter over the stock lens would do, [Paul] got a painful faceful of sunshine when he tried framing a shot. Turns out the phone body was not big enough to blot out the sun, and besides, the stock lens doesn’t exactly make for a great shot. So with an iPhone telephoto lens affixed to a scrap of wood and a properly positioned filter, [Paul] has a simple rig that’ll let him get some great pre-totality shots of the eclipse, and it’ll be easy to bust out the phone for two minutes of totality selfies. Looks like this setup would be easy to adapt to other phones, too.
We’re all over Eclipse 2017, from Hackaday Eclipse Meetups in at least four different points along the path of totality to experiments on relativity to citizen science efforts so you can get in on the action too. Mark your calendars – August 21 will be here before you know it.
We are all (hopefully) aware that we can be watched while we’re online. Our clicks are all trackable to some extent, whether it’s our country’s government or an advertiser. What isn’t as obvious, though, is that it’s just as easy to track our movements in real life. [Saulius] was able to prove this concept by using optical character recognition to track the license plate numbers of passing cars half a kilometer away.
To achieve such long distances (and still have clear and reliable data to work with) [Saulius] paired a 70-300 mm telephoto lens with a compact USB camera. All of the gear was set up on an overpass and the camera was aimed at cars coming around a corner of a highway. As soon as the cars enter the frame, the USB camera feeds the information to a laptop running openALPR which is able to process and record license plate data.
The build is pretty impressive, but [Saulius] notes that it isn’t the ideal setup for processing a large amount of information at once because of the demands made on the laptop. With this equipment, monitoring a parking lot would be a more feasible situation. Still, with even this level of capability available to anyone with the cash, imagine what someone could do with the resources of a national government. They might even have long distance laser night vision!
It may seem trivial at first, but the effect [Dan] gets when using binoculars as a telephoto lens is surprising. The images are well in focus with great colors. This technique not only brings your subject mater closer but also provides a depth-of-focus feature not normally available on simple cameras or camera phones.
The proof is in the example footage found after the break, but you’ll also find a video tutorial detailing the build. [Dan] already had the expensive components are a pair of mini binoculars and a Kodak Zx3 pocket camcorder. The camcorder is the same form factor as a smart phone so using different hardware will be a breeze. He started off by building a prototype out of paper. Basically it’s a bracket that properly aligns the camera with one lens of the binoculars. Once he had everything lined up he transferred his measurements to some sheet metal. The bracket for the binoculars is attached to the one for the camera using bolts and wing nuts to make it adjustable. One important part of the design is to gut a hole for access to the binocular focus wheel.
Continue reading “Binoculars As A Zoom Lens”