I've already had a couple of emails about my use of a viewing frame, asking how to make one or where to buy one or how to use it. My current frame is a simple cutout, but I have been thinking for a long time that what's really needed is an adjustable viewing frame.
I gave it some thought and realized that the most efficient way to do this was to use styrene (which can be scored and snapped and easily glued), that only two sides need to be adjustable, from perfectly square to reasonably panoramic.
A little work with pencil and paper and I think I have come up with a possible design. I'm going to build it in the next few days but thought I'd share the idea and perhaps someone else will come up with an even better design.
Cutting out that rectangular hole was a hassle, so better is a bunch of rectangular pieces that can be snapped and don't need drilled or filed or anything, so here's the idea.
The total size is 6X6 inches, the maximum opening is 3X3 inches, the minimum 1/2X3 inches. There are two vertical pieces 6X 1.25 inches, held with two horizontal pieces across the top and bottom, making for a 6X6 inch square. There are 2X3.5 inch 'sliders' which sit between the verticals and act as curtains which slide up or down as needed. Fully apart they make for an opening 3.5 inches high, closest together they are half an inch apart. They are held in place by a narrow cover sheet from top to bottom.
I'll finalize the design and show you pictures of the assembled viewer if it works as expected. I'm thinking it would be nice if it had a detent of some sort so that unless you deliberately change things it will sit at the 2X3 ratio of the typical dSLR.