Wednesday, August 02, 2017

made filter adapter

Made a solar filter adapter for the DSLR camera. Having not planned ahead to arrange to purchase a sheet of baader solar film, I decided to build it around my existing solar filter. A somewhat large filter...

sketch of adapter box with output tube

To repurpose my Kendrick visual solar filter, which is for an 8" SCT, I needed a large box to serve as the frame. Ideally, I wanted something like a shoebox. Relatively thin or shallow with a removeable top. Tried a shallow square box from digi-key. Not big enough. A box for a dozen wine bottles was too big and bulky and awkward.

I stumbled across a "tray," a corrugated cardboard tray for soda cans (or bottled water). The depth was perfect; the width was perfect; I could cut down the length. But did I have another? Amazingly, I found another tray in my packing materials supplies.

front element, solar filter held in place with tabs

For the front piece, I squared it, and glued the tabs. Could not find my container of white glue so I hope the Elmer's glue stick adhesive will work. I figured out the locations for the three tabs and glued them in place. I cut a large circle, centred, slightly larger than the filter's clear opening. Shimmed one of the tabs after a test fit (should have done the big circle before setting the tabs). Marked and drilled holes for two of the tabs...

Looks like it will be pretty light proof.

back element with output tube to fit camera lens

For the back piece, I sized it to fit over the front box, squared it, glued it. I cut a centred circle for the clear opening of the 18-55 lens hood. I shortened a bread crumbs tube for the camera lens in its retracted state and cut tabs. Centred and glued it to the back plate.

Let everything dry...

front and back elements mated, Kendrick filter installed

Will test for vignetting and weight issues...

Also wondering if I should paint it...


It works! Tested by shooting my Tizio lamp with halogen bulb on the II (high) setting.

halogen bulb filament

Canon 40D, 18-55 lens at 31, auto-focused, 1/15, f/4.5, ISO 1000, incandescent (tungsten) WB, RAW, DPP.

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