Underwater photography snoot with beam splitter

Summary

This is a design of a snoot for an underwater strobe. The snoot uses a beam splitter to put the beam from a torch and the strobe on the same exact path. This means that the light from the torch provides an accurate approximation of what the strobe light will hit.

The design assumes a beam splitter of size 40X33mm. The dimensions are based on the splitter I I got from this product (Khet Beamsplitter Expansion). Back then it cost ~5$ and right now it is much more expansive. This instructable suggests that cutting a rectangle from an old CD case will do the job but I didn't try it yet.

The design is fairly modular:

Snoot body The basic piece of the snoot (snoot_body.stl)

Strobe interface Included are interfaces for Inon Z240 and Z330. Others can be easily designed (just make sure that the opening is directly above center of the strobe flash tube). Both interfaces connect to the snoot body using a twist and lock mechanism (interface_lock.stl) which might require a tool to lock (tool.stl)

• Torch The current design has a holder for SOLA 800/1200. However, one can design a replacement holder for other focus lights (again, just maintain the basic interface to the snoot body)

The snoot to torch interface requires M4 screws and bolts (either water resistant stainless steel or preferably nylon screws and bolts). The sola holder has a lock piece to hold the SOLA torch by the 1" ball connector. The lock is held in place by another pair of M4 screws, or a long (4cm) screw.

Snoot heads Included are interchangeable parts that allow to narrow the beam of the snoot (5/10/15 mm). The heads are fastened by a twist and lock mechanism.

Fiber head The fiber head connects a fiber optic cable to the snoot. The cable is held in place by a screw mechanism. There are two different versions of the locking cap - a smooth one and a ribbed one that is easier to manipulate.

Fiber optic cable I use a 8mm solid core end glow fiber (that can be bought for example here). The outer diameter of the fiber is 10mm. You can use other diameters but you might need to redesign the capture ring.

• Fiber tip This is optional. The tip is easier to hold and point and also has a "focusing" mechanism that narrows the beam. Attachment of the cable is again by the same screw lock mechanism.