Budgie Sony A7-series Shift-and-Stitch Adapter

Use your full-frame Sony E-mount (FE) body to capture images up to 48x36mm -- generously larger than the 44x33mm sensors people are often calling medium format. I argue that's really best considered as multi-aspect 135 film (35mm) format for getting the largest possible coverage sampling using a designed-for-full-frame lens.

Budgie is an adapter for Leica M to Sony FE -- except it does offset shifting and includes a tripod mount. The name comes from the idea that the camera can be budged +/-12mm relative to the mounted lens to capture multiple images for stitching. The diagonal of a 36x24mm full frame is approximately 43.27mm. However, that's with the standard 3:2 aspect ratio. In 1:1 (square) format, a lens that can cover that diagonal also should be able to cover a square with approximately the same diagonal, which would be 30.59x30.59mm. In infinity:1 (the limit on panoramic aspect ratio), a lens covering that diagonal should be able to cover 43.27x0mm. In other words, all aspect ratios are contained within a 43.27x30.59mm capture rectangle -- which easily fits inside Budgie's 48x36mm space. Very few full-frame lenses will produce high-quality coverage of the full 48x36mm capture space, but quite a few will cover more than one would expect; for example, most lenses I've tried can cover a 36x36mm square image. In any case, using a 42MP body, such as the A7R II, stitching two (or better, three) shots will get you an approximately 48x36mm stitched image with about 84MP effective resolution. If you have a body like the Sony A7R IV, combining this with the camera's "pixel shift" will give up to 482MP of image detail! Of course, the image stitching software might give you any number of pixels, but the point is that you can get that medium-format look using your existing full-frame camera and lenses.

Why Leica M? For the same reason the TechArt Pro LM-EA7 uses it: nearly all old lens mounts can be adapted to Leica M, so this adapter is reasonably universal. For example, to use a Canon FD lens, simply mount a Canon FD to Leica M adapter on this and then mount your FD lens on the front. Not only are lots of adapters commercially available, but I've also designed and posted free 3D-printable M adapters for: Argus C3, Minolta/Konica-Minolta AF / SonyA, Canon FL/FD/FDn, Minolta SR/MC/MD, M42, and Kiev 10/15.

Notes: There have thus far been five major versions of this adapter. The first two worked well, and the second was used for the images shown here, but the mounting screws could hit the EVF shroud while mounting/unmounting. The third and fourth versions allowed the weight of the camera to flex the E flange too much, making focus imprecise. Version five, 20210621, is simplified, but features three-point clamping that forces the E flange to remain flat... while still (just barely) mounting without bumping into any part of the body of the A7, A7R II, etc. There was even a last-minute tweak to the 20210621 version (not shown in the photos) to remove one of the half-inch screw reinforcing collars to make more clearance for some A7-series models.

Also note that, although you could use Budgie with an APS-C E-mount body, the result couldn't be larger than about 39.6x23.6mm. Thus, for APS_C, it's probably more interesting to use APSC2, which also uses full-frame lenses with an M mount, but captures four offset-rotated shots, giving an image of approximately 30.6x30.6mm.