Telephoto Lens Without The Fiscal Pain

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.

20 thoughts on “Telephoto Lens Without The Fiscal Pain

  1. I would humbly encourage these creative DIY optics champions to put a few more diagrams, photographs, and STL previews of their clever wares to upgrade their “zen” minimalist web site from the current “black box” to more of a “wow.” The artistic photos are definitely a good start.

  2. I was looking at this yesterday and can’t find any information on what lens to purchase with this. They have all the files needed to 3d print the holder for the lens, and a link to a website to purchase the lens from (but also suggest ebay as a possibility), but no info on what to search for.

    I do like this idea and want to understand more. I want a super-wide angle lens for shooting fireworks (14mm on a full frame isn’t quite wide enough when I put the camera in the middle of the show pointing straight up) and I don’t want an expensive lens as I have burning stuff falling on the camera during the show.

    1. Expensive lens or not, you could always put it in a box and then place a piece of acrylic or glass over the top. Might get some fun visuals of paper firework casings and ash piling up in frame as the show goes on.

      1. currently I’m using haze filtter on a 15mm $100 lens (on my canon 6D), I typically shoot at ~F45 with multi-second exposures, after the last show, I don’t know if the filter can be cleaned (not all the stuff is coming off of the camera without scrubbing hard enough to dislodge the rubber)

  3. I am worried about dust from plastic parts rubbing against each other. Some of that will be kept away from the camera sensor by the glass, but I am even worried about the dust from the plastic when screwing it into the camera (which is also a worry I have about 3D printed lens adapters). Is there something they did to solve this issues?

    1. Could always spray down the 3d printed parts with sealant and let cure before assembly. Maybe wrap teflon tape around the threads? I don’t think you’re gonna get flawless optics, alignment, and cleanliness out of it no matter what, so it might involve accepting a certain amount of “character” in the final product.

  4. I tried looking in to this. I can’t find a 65mm diameter lens like this on Surplusshed,ebay,aliexpress or alibaba. I like the idea of this I fear I have fallen at the first hurdle.

    Any advice welcome?


  5. I buy a lot of old lenses (in fact too many). I try to stay under $75 and only on special occasions $100. You can get a lot of great lenses actually. My newest ones are currently Vivitar 200 f/3 for $100 (great for portraits), Zenitar-M 50/2 for $150 (can achieve >90 MPx) and Vivitar 24 f/2.8 for $80 (great for street photography).
    Reusing old gear is also way to go.

  6. Strictly speaking, this is NOT a telephoto lens. It’s just a single lens with an arbitrarily long focal length.

    By definition, a telephoto lens includes a negative rear element to make the physical length of the lens shorter than its optical length.

    1. first time I’ve heard that definition. I’ll say that in practice not much length is saved (canon 300 and 400mm lenses are within a couple mm of their focal length, when you consider the mount to sensor distance, and others like the famous 70-200 F2.8 L lens is almost 200mm even before you account for the mount to sensor difference

      1. The definition is many decades old, but most folks don’t recognize the distinction and, ignorant, just blithely use the term to mean any long-focus lens.

        Which Canon lens are you talking about? In 300mm the older ones are about 200 mm overall. Even the EF 2.8 is only 248 mm, and it’s got all the stabilization stuff in the optical path too. If you quibble and add the flange distance then you also need to subtract the filter mounting ring etc. distance on the front, and it’s still shorter than the focal length.

  7. Thumbs up for The Surplus Shed: they approach what Edmund were in their heyday. Apart from that I find myself wondering: there is a vast number of high-quality coated (and sometimes aspheric) lenses available from old 35mm gear: could these be used as components for good lenses for the smaller formats now dominant?

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