I’ve wanted to make my own camera lens for a little while now, as the idea of controlling the light to get the focal length, aperture and aberrations just right intrigues me. I was initially inspired by this video from Mathieu Stern, where he takes a single lens element and designs and 3D prints a barrel for it to make a simple lens for his camera.
While I certainly respected Mathieu’s lens and was impressed by its results, I thought I’d like to make something a bit more complex. This would allow me to
- reduce aberrations and distortion greatly by using multiple lens elements,
- learn a lot about optical system design,
- learn about the design, manufacture and assembly of axial assemblies like lenses, and
- gain more useful skills in my CAD software of choice, Autodesk Fusion 360, particularly when it came to CAM.
However, with a bit more searching I then came across this video from Mats Wernersson where he shows incredible craftsmanship while making his own lens from scratch, including grinding the lens elements himself.
I was truly astonished when I saw this video. Seeing the lens in the thumbnail, I really would have thought it was a commercially made lens were it not for the fact it didn’t include a company name. The level of dedication shown to the project must have been immense, with Mats even making the machines that ground his lenses.
I was also amazed by how Mats turned his own barrel for his lens, with several parts all coming together to form the overall body. Seeing the pieces being cut from the raw aluminium billets really made me want to learn more about design and manufacture of parts like that and how they are assembled.
His DIY anodisation of the parts and the fine detail in the numbering of the aperture and focus rings were really the cherries on the cake. Overall, I was blown away by the level of care taken in the design and manufacture of this lens, and the images it produced looked stunning.
I knew though that design and manufacturing a lens to that standard was certainly beyond my abilities. Instead, I decided to come up with a lens somewhere between Mathieu’s and Mats’. This idea formed the basis of my next project.
I am hoping to produce a lens for use taking portraits, or pictures where you’d want the image to be similar to what you’d see with your eye in terms of focal length. For that reason, I will aim for a focal length of around 31mm. Taking into account the 1.6x crop factor of the APS-C sensor in my camera, this will give a focal length equivalent to shooting at 50mm on a full frame camera, which is often regarded as the optimum focal length to match what the eye sees. For portraits, I will want to have the capability to produce some nice bokeh, so will try to make a lens with a maximum aperture of f/2.5 or less, preferably around f/1.8 or so.
I will probably use the free version of WinLens3D for the optical design, and will use Fusion 360 for the mechanical side. While I certainly don’t expect to make significant progress on the project overnight, I’m hoping that with lots of spare time over the summer I should be able to at least come up with a reasonable optical design and hopefully make a working prototype. At the very least, it should serve as a useful exercise in learning more about optical design, CAM and design for manufacture (DFM).
Update 19/4/19: I realised not long after writing this page and watching Mats’ video that designing and building a lens is currently far outside of my skillset in terms of optical and mechanical design, so I’ve shelved the project for now.
I’d certainly be interested in returning to it at some point, but for now I’m focussing (no pun intended) on my university final year project (a CubeSat docking simulator) and on electronics projects using USB-capable microcontrollers such as the ATmega32U4. I’ll write and publish some blog posts about these projects in the hopefully near future, once I’ve finished my Alpbach series.