M42 Flange for Tamron Adaptall2 Lens

thingiverse

I purchased a Tamron Adaptall2 lens solely to disassemble its metal ring and repurpose it for another Tamron lens repair project. The thought of discarding a perfectly good lens was unbearable, so I decided to give it new life instead. To access the ring, I unscrewed the three tiny screws that hold it in place. Next, I removed the flange, springs, lever, and plastic frame underneath. Once these components were out of the way, I reattached the flange using the original screws, taking care to align them with the correct holes as this part only fits one way. With the metal ring now separated from its original housing, it can be used to manually control the aperture on any Tamron lens that accepts an M42 thread. This opens up a world of possibilities for photographers who use tilt-shift and macro focusing helicoids, which are widely available in this configuration. The flange focal distance has been set to 45.46mm, ensuring that any Tamron lens attached will focus correctly within its full range, provided the M42 adapter is designed properly for a 45mm flange distance. Fotasy makes some excellent adapters that meet these specifications. This repurposed metal ring has been successfully tested on my Tamron 58A 70-210mm zoom lens and appears to be compatible with other Tamron Adaptall2 lenses as well. However, I'm choosing to leave those alone so they can continue working in conjunction with my Tamron teleconverters.