I don't know about you, but I have a heck of a time with telephoto zoom lenses in keeping the zoom and focus rings separate. No matter how hard I try, I always get caught up in the moment of the scene in front of my camera and as I reach up to the zoom to change it (still looking through the viewfinder), I grab the focus ring instead and change it. Okay, I admit it, I get lost in what I am seeing and literally lose touch with my gear. If I am after some careful focus point like on these buckwheat flower seed heads (a great fall color, by the way), it is really frustrating to have to start over again.
Well, I found something that really works for me. It might seem a little crazy and odd, but I'll use anything that makes my life easier! I had been looking for a silicone jar opener that can be used for video change of focus. So I was in a local cooking wares store and came across this strange penguin-shaped silicone grip for unscrewing the lid on a jar. I thought, Why not? It wasn't much money.
It fit my long zoom perfectly well and I realized immediately it did something I had not expected. It stuck up from the surface of the lens and provided a tactile change to the lens that made the focus ring really easy to find. And of course, if the focus ring is easy to find, then the zoom lens is also easy because it is the ring without the blue penguin on it!
I liked this so much that I left the grip on the lens. The blue isn't too bad (it also came in a hot pink that is a little too flashy for me!). So if you have trouble keeping from grabbing the wrong ring on your lens, check out a cooking wares store and see what they might have in silicone jar openers!