Build complex toys and simple tools
by Tony Karp
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So there I am with my brand new DMC-FZ18, all ready to go. I turn the camera on and get a nasty message in the viewfinder. REMOVE LENS CAP AND PRESS > BUTTON. Whoa! Can't turn the camera on with the lens cap attached? I follow orders and the camera is on, but the lens protrudes from the camera, looking rather exposed to the hard knocks of the real world. And when the lens is at full telephoto, it sticks way out.Thus began a quest that has gone on, as time allows, for the past two months.The problem is that the DMC-FZ18 is the first Panasonic superzoom camera to have a wide angle lens, and this is part of the price you pay for that feature. Older models had an adapter tube that went over the lens that protected it and let you turn the camera on without bumping into the lens cap.But the newer superzooms, with their wider lenses can't use a protective tube like the older models as it would cause vignetting (darkened corners) when the lens is at its wide angle setting. The Sony DSC-H9, whose lens is not quite as wide as the DMC-FZ18's, comes with a huge adapter tube, almost three inches across the front, that won't take a standard-sized filter.Here are the requirements for this quest:1. Allow the camera to be turned on with the lens cap attached.2. Allow the use of standard filters.3. Act as a sunshade.4. Protect the extended part of the lens from impact.5. No vignetting at 28mm equivalent focal length.6. Assembled from available components.The first ring is the plastic sunshade adapter ring that comes with the camera. But even with this extension, you still can't turn the camera on with the lens cap attached. Bummer. The front thread of the adapter ring turns out to have a non-standard thread size -- about 55.8mm. I try adding a 55 to 58mm step-up ring and it falls out.After some thought, I take the 55 to 58mm step-up ring and glue it into the sunshade adapter ring. This works. You can now use a commonly available 58mm lens cap, and the camera doesn't go crazy if you turn it on without taking off the lens cap.But the lens still extends beyond this at telephoto settings. So I get a bunch of 58mm extension rings. These have a 58mm thread front and back. They're made for moving a filter away from the lens. I put the first one on and everything is fine. But a second one causes vignetting at the wide angle setting.Time to go bigger. The next extension is a 58 to 62mm step-up ring. This makes the "tube" a little bit longer. It's the setup shown in the photo above. But an additional 62mm extension tube causes vignetting, so it's the end of that road.I guess I could continue along this path, perhaps with a 62 to 67mm step-up ring, but I've already met the requirements listed above. The only thing you can't do with this setup is put the lens cap on when the lens is at full telephoto. Other than that, it's good to go.Here's the final setup:1. Lens hood adapter ring that came with the camera.2. Step-up ring from 55mm to 58mm, glued into the lens hood adapter ring.3. Extension ring, 58mm to 58mm.4. Step-up ring 58mm to 62mm.5. Lens cap, 62mm.And that's it.
Copyright 1957-2023 Tony & Marilyn Karp
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