That Time I Built an “Air-Gap Meniscus” Lens – By Dave Powell
Long ago, I tried to shoot landscapes using a macro-close-up filter as a lens. I taped the filter to the front of two nested cardboard “focusing tubes” and attached them to my Fuji X-Pro1’s lens mount. I did get images, but wasn’t impressed. Though fairly sharp in the center, they blurred massively toward the perimeter. And the cardboard tubes didn’t slide easily enough for fine focusing. So I dropped the idea.
Until last week, when I stumbled across an old forum about removing (and even chiseling) “meniscus” lenses from vintage folders and plastic-fantastics to mount on medium- and large-format cameras. The photographers reported decent results.
It got me thinking (always dangerous). My original macro-close-up “lens” was meniscus-shaped– concave on the back and a little more convex on the front– but it was also proportionately thinner than most of the meniscus lenses in vintage cameras. So what would happen if I simulated a thicker meniscus by screwing one close-up filter onto another?
If the combination proved to be a decent lens, it might also address a problem reported in the old forum. Most of the meniscus lenses harvested from 35mm and medium-format cameras had fairly small diameters… which made them “slow” for large-format shooting. My 55mm macro-close-up filters would be comparatively huge, and produce a faster lens.
