Hood Clip for Sigma 400mm/5.6 lens

thingiverse

The classic Sigma 400mm lens boasts an integral hood that can be effortlessly slid forward to minimize flare, ensuring optimal image quality. However, its secure positioning is solely reliant on Art's design and the gentle friction provided by the soft inner coating on the hood as it comes into contact with the wider part of the lens. Given the age of these lenses, tilting them upwards becomes a challenge, as any movement will cause the hood to slide back to its original position. This limitation is a result of the lack of mechanical locks or other securing mechanisms. Fortunately, this issue can be mitigated by employing a simple plastic clip that wraps around the wide part of the barrel and provides a light grip. The clip's tabs can be easily released with a slight squeeze, allowing for smooth adjustment as needed. When slid up behind the extended hood, it remains securely in place, even when held vertically. The FreeCAD spreadsheet offers a convenient means to fine-tune the tightness of the grip, enabling users to achieve their desired level of secure positioning. Nevertheless, it's essential to note that small adjustments to the inner radius can lead to significant differences in the clip's effectiveness.