So you want to 3D-print a camera accessory like a lens adapter, extension tube, or a custom lens? You’ll need a lens mount design to go along with that!
We’ll clone the required dimensions from the mount found on a lens (for ‘male’ mounts) or camera (for ‘female’ mounts). One way to get an example of both the male and female mount at the same time is to buy an extension tube for your desired mount, e.g. I’ve found the ones from Meike to be good. Avoid tubes with plastic mounts as these are less accurate and may have draft angles that make them difficult to measure. Get a tube that has electronic contacts (for autofocus) so that you can use the dimensions of those as a reference as well.
You’ll need a pair of calipers for measuring the lens dimensions.
For this example I’ll show the process of modelling a Sony A lens’s ‘male’ mount using Fusion 360.
Start by taking a reference photo of your lens mount. Be sure to align your photo straight-on with the mount so that the image isn’t skewed. If you can stand far away from the mount and zoom in when you take the photo this gets you closer to an “orthographic perspective”, which means that features won’t appear to erroneously grow larger when they’re closer to your camera.
Here’s my shot:
