Sharing a simple flap shutter built for this ULF lens - a 36" f6.3 aerial lens.
My requirement is that it need to be able to allow to open or close it from a distance when shooting my self portrait.

For the lens with a 6.5 inches diameter it would be hard to find a commercial shutter like the Packard Shutter for it so I decided to take a DIY approach in the design. At the same time, I took advantage of the 8kg weight of the lens to create the pull down flap design as it would be difficult to pull of the lens off the camera table. Using rubberbands while primitive is a simple and easy way without sourcing for compression springs and such.

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Plywood acting as the shutter flap attached to the wooden lens support built to support the big lens

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Powered by rubberbands

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Simple toggle wood to attach rubberband to eye screw

More details in youtube video