Mine also cost a fortune, but it is some of the most durable tape I've ever used. It also removed without leaving any residue. I was able to put up some electrical decorations in my entry way on the side opposite the electrical outlet. Taping a piece of durable plastic flashing over the cord allowed foot traffic to pass without tripping, damaging the electrical cord and removed without leaving a residue. I'm now keeping an extra roll around to be sure I don't ever run out.
When used to tape a lens barrel so that the focus collar doesn't move, I've never had any residue left that could attract dust, etc. I do periodically clean all my lenses, externally as optically, but I have a great deal of confidence in using gaffer's tape when I need something durable and non-destructive.
My wife also uses it to tape down shields over expensive carpet when we've had a very in-climate turn of weather at a formal gathering. It saved a cleaning bill.
OTOH, I've never had black electrical tape that I've trusted to not contaminate a surface, over time and especially with heat, the adhesive becomes unreliable. It's not meant to be residue free, it is meant to be flexible and pliable. That said, I also have a bunch of gray electrical tape wrapped around a tripod leg, but it's there to secure emergency rain gear if needed - e.g. a black garbage bag in the bottom of my camera bag.
Roger It's still, ISO, aperture and shutter-speed, right?