There are a number of accessories out there that can change the performance of a lens. Teleconverters extend the focal length, a speed booster increases the maximum aperture, an expander magnifies the image circle so that a smaller lens, say a Super 35 lens can be used with a full-frame sensor, and there are also adapters that allow you to mount a lens designed for one camera body to another.
Additionally, diopters and extension tubes are also on the menu. While both different, they perform a similar task by magnifying the lens and shifting the minimal focus distance allowing you to get macro shots without using a macro lens. While diopters are filters made of glass – like those made from Lindsey Optics – and are generally dropped into a matte box, an extension tube sits between the camera body and the lens. It's not an optical element, so no glass is involved.
Duclos has introduced a 15mm LPL Macro Extension Tube that echoes the same performance and build of its original PL Macro Extension Tube as well as its other extension tubes. As the name suggests, its compatible with LPL mount lenses like the ARRI Signature Primes.
The accessory has a stainless steel design and is said to have precision-like tolerances with a flat finish to reduce light strays. Duclos says when attaching the 15mm LPL Macro Extension Tube to a ARRI 58mm Signature Prime, it will give you an approximate magnification of 0.435x over its original 0.185x. The downside of course is the loss of infinity focus which comes with using any extension tube. Duclos also mentions the extension tube will not work any anamorphic lens. However, by attaching the extension tube to the lens filmmakers should see an increase in magnification without it impacting the image quality.
The 15mm LPL Macro Extension Tube is priced at $350. The company expects longer lengths to be available soon.