Non-Helicoid Zoom TLR

TLRs don't generally use helicoid focusing, instead mounting the lens pair firmly on a panel which is racked in and out in one linear action.

In this design, instead of the lenses being mounted on a single plate, pairs of elements are mounted on a single plate, thus a sandwich or laminate of plate/element sets is formed. The gap between each plate and its neighbours is actuated using an appropriate technology and controlled with the aid of feedback, via a lever/knob under the users control.

So, unlike most zoom lenses people are accustomed to currently, these zooms would not use a rotary gearing (or helicoid) to arrange the element positioning, nor to focus. The distance between elements and cells could be controlled electronically, to arrive at different focal length arrangements, and also to affect the overall focal distance.

A typical TLR has a rotary knob on one side (Rolleis seem to have alternated which side, on different models), which is the most common TLR pattern, although others exist: the Mamiya uses a pair of knobs at the bottom front edge, the Minolta Autocord uses a lever under the taking lens, the Ricoh Diacord does use a form of helical focusing with opposing levers poking out each side.

For this Zoom TLR, it might be nice to have a complex solid-feeling single control that you rotate in the normal manner for focus, but push forwards or pull back for zoom. This is interpreted by a cpu into appropriate spacings of the element and cell sandwiched layers.

I'm not sure what mechanisms should be chosen for the actuation, but they should maintain perfect parallel motion between cell plates.

In most other respects, this would remain similar to a contemporary TLR: it would use 120 film, it would feature TTL metering and flash control, it would be compact, ergonomic and robust.