Thanks eurekaiv. I am following the instructibles how-to link that I previously listed but I cannot (even with a bit of elbow grease) spin off the inner ring on the lens that looks like it holds it together. It looks like a splined tool would do it. I just looked at the Pen D on line and my trip 35 and they look like they may open a bit different. Do they both open up by spinning off the inner ring? Thanks! Don.