The Alum Anamorphic is back, for a 3rd, all new edition! The new Alum v3 has an new optical design, utilising high index glass, which makes it 30% smaller than the previous versions. Field of view is also slightly expanded, allowing for better compatibility. It also now comes in a silver coloured version
The Alum is a 1.33 focus-through anamorphic adapter, and is a very simple two element formula. The adapter is designed primarily for use on small (rangefinder style) 35mm lens. It works quite well on smaller formats with an equivalent focal length as well. The adapter is optimised for shooting around f/4 and is focused at infinity.
The 3rd edition now comes with 4 filter threads in the box, 39,43,46 and 49mm. As opposed to the 2nd edition where they were sold separately.
1.33x Anamorphic Adapter
The purpose of this anamorphic adapter is to give you some interesting lens effects, and give you a way to shoot 2:1 aspect ratio on your camera without cropping. The adapter causes some image degradation, and ads coma and astigmatism.
Anamorphic adapters change the focal length of your lens in one direction, and not the other, therefore the two focal lengths (horizontal and vertical) now focus at different rates. In more complex adapters and lenses, you can compensate for this optical propriety with different focus mechanisms, in this case the adapter is focused to give the sharpest results at infinity, at any other focus distance, the two focal lengths will be focused differently and you will get increased astigmatism in your image (blur). It’s recommended you stop down the lens to achieve sharper results.
If you’re looking for a sharper - more integrated solution, check out the bismuth m mount anamorphic
Use cases
Sample Shots on Initial Prototype, V1,V2 and V3, image quality does not vary hugely, V3 is mainly smaller.
Sample Gallery
Story
The Alum was my first foray into lens design, and started as a plastic prototype that I milled out of acrylic and polished by hand in 2022. About two years later, the first edition of the adapter was released in March 2024 and sold out almost immediately, the second edition was available for pre-order in June of 2024 and started shipping in early 2025 due to production issues. I’ve made a number of videos documenting the project, that you can find here
On the Second Edition, It was possible to shim the adapter, moving the front lens forward to achieve a different optimal focus point, mainly longer focus distances. The shims can be 3d printed with some template files found below.
![[PRE-ORDER] ALUM anamorphic Adapter 1.33x 3rd Edition](https://images.squarespace-cdn.com/content/v1/5a3e1230cf81e03172cafd98/3c5ee8d8-3ad0-49e1-95bd-6fc026275590/DSCF6204.jpg)
Expected Shipping September 2026
US BASED CUSTOMERS - SHIPPING EXPECTED OCTOBER-NOVEMBER DUE TO TARIFF RELATED LOGISTICS
Larger aperture designs and designs with more bulbous front elements like the 35 steel rim summilux, or voigtlander nokton 35mm f/1.4 may see a hard vignetting at the edges of frame - due to the curvature of the front lens, the edges are further than the center from the anamorphic, and therefore would require a larger adapter.
The 3rd Edition of the ALUM anamorphic adapter is here!
This version comes in with a brand new optical design utilising higher index glass and full multicoating. The general layout is still the same, it’s a two piece design with a front negative lens, and a rear positive lens, but the adapter as a whole is now almost 30% shorter than it was previously, bringing the size down to just over 3cm!
The Alum is an experimental anamorphic adapter. It comes with 39,43,46 and 49mm filters which you can swap out with the help of a screwdriver. The adapter screws into your taking lens, just like a filter would, and sits right on top.
This lens works best, and is optimised for small lenses of 35mm focal length on full-frame (35mm format) or smaller. Leica 35mm summicron, Voigtlander 35mm Color Skopar, or even Fuji X100 cameras should work well.
The 3rd edition is optimised for infinity focus, and is a fixed (also sometimes called ‘focus through’) adapter, this means it will be at its sharpest at infinity, and astigmatism will increase as you focus closer.
When purchasing the adapter you will also receive the .step files in the confirmation under a GNU GPL license. Your are then free to use the files as you wish, to make different casings, mounting adapter options and so on. You can share them with your friends, and share the changes you make.
Size : 54×54×31mm
Weight : 175g