Extension Tubes are one of the staples in the macro photographer’s toolbox. This article does not go into the background and application of extension tubes, for this I refer to the excellent article of Shuttermuse. Instead it focusses on one specific aspect of Canon extension tubes that I had not heard of before: out of the box flocking.
Canon extension tubes are way more expensive compared to other brands, like the popular Kenko tube set for example, even though there is almost or no visible difference between them. I use a set of Kenko tubes for many years already.
The past years I have spend a lot of time and effort improving my photography which drilled down to improving the light and subject magnification. For the latter extension tubes are a great option. However when used in combination with a flash the resulting photograph would frequently contain an annoying bright spot.
With some post processing the spot can be cleaned up, but it involves some addition steps and is undesired hassle.
Examples of a bright spot as result of the use of extension tube light reflextion
At first it seemed like the applied white background was the cause but reposition etcetera did not solve the issue.
A funny YouTube movie featuring extension tubes, casually mentioned these may cause reflections that would turn up as bright spots in the photograph, and that the solution is to flock the inside of the tube(s), i.e. cover the reflective surface with a non-reflective material. Right, let’s do that.
Some astrophotography sites recommended D-C-Fix Velours Black Velvet as flock material. A few hours after the adhesive material had been delivered (two rolls for €21,-) the Kenko tubes were fitted with the anti-reflective layer and the bright spot did no longer appear in the test shots.
Problem solved, albeit with a slight caveat that the material loosens at the stress points and needs to be pressed down every now and then. Possibly the roles were old stock as the glue does not feel very adhesive, or the small diameter of the tube adds stress, or I just didn’t properly apply the material.
Recently I had use for another tube and bought a nicely priced second hand Canon EF25 II. To my surprise the insides of this ring are already flocked.
For me this is an important feature, so from now on I will only buy Canon extension tubes (I recently obtained another used one). They are more expensive than alternatives, especially when bought new, but regularly a second hand item is offered for half price. For me it is worth it since macrophotography is already time consuming enough without this kind of additional hassle ✌️😅
References1 Nederlands Soortenregister