The ACTi PMAX-0104 Extension Tube (White) can be used to add 21.3" (540mm) to the length of your camera mount, so that you can install the camera relatively low, for example half-way down from the ceiling. 

For Lower Camera Suspension    For Wall, Gooseneck & Straight Mounts

Used with a mount when the camera needs to be suspended much lower

Compatible with gooseneck, wall, and straight tube mounts

Related Questions and Answers

Q: 1. Would inserting one of these (or any tele converter) between the RF 100-500 lens and the RF 1.4X (or 2.0) tele extender, allow the lens to extend BELOW 300 mm? If so, would the lens then NOT be able to focus to infinity? Thanks.

A: Teleconverters and extension tubes have different usages and are not often used simultaneously. A teleconverter is is designed to increase the focal length of a lens by the multiplication factor listed on the teleconverter, giving you additional reach to your subject. Extension tubes are designed for macro photography, and are designed to reduce the minimum focus distance of your lens while increasing magnification, and also eliminate the ability to focus at infinity or use the lens for normal shooting. Hypothetically, using a teleconverter and an extension tube simultaneously with a telephoto lens would reduce the lens' would allow you to focus closer than the lens' listed 2.95 feet (90 cm) minimum focus distance, and would also prevent you from focusing at infinity, essentially making it a long macro lens. Unfortunately, as this is an unorthodox setup, and as the Canon Extender RF 1.4x and the Canon Extender RF 2x is designed to connect directly to the lens (the optical element on the teleconverter is designed to sit inside the rear of the lens for optimum optical performance), I cannot state if the setup you describe would work, nor if the lens would focus properly with the teleconverter's optical element out of its designed alignment inside the lens, and this would not be something we could test.

Q: 2. Can I assemble two sets of two extension tubes, for a total of four, and attach the new 105mm Z micro lens to them? Would this result in approximately 1.58 magnification given the lens is 1:1?

A: Unfortunately, this set up has not been tested in this manner so the results may vary.

Q: 3. Are these automatic or only manual?

A: These extension tubes have electronic contacts that maintain full autofocus and auto-exposure functionality for seamless use.