APSC2 (APS-C Squared) Rotate-and-Stitch Adapter

prusaprinters

Use your APS-C Sony E-mount body to capture the largest square format images most full-frame lenses are almost certain to cover -- as shown in the last three images above. This is a simple four-part adapter for Leica M to Sony E -- except it is offset and rotates. The idea is simple: the diagonal of a 36x24mm full frame is approximately 43.27mm, somost full-frame lenses should be able to cover a square with approximately the same diagonal, which would be 30.59x30.59mm. Sony APS-C is approximately 23.6x15.6mm, thus by offset rotation in 90-degree steps it should be possible for four shots to cover up to 31.2x31.2mm. Of course, alignment is never perfect, but allowing for that, it's still possible to get about 30.6x30.6mm... allowing for minor stitching errors, etc., let's call it 30x30mm. Using a 24MP APS-C body, that means you'll get roughly 58MP worth of scene detail (although image stitching software might give you any number of pixels). Of course, you'll need things mounted firmly while rotating to hold fractional mm alignment, but it is surprisingly easy to do that by clamping the lens. 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 several major versions of this adapter. The first two versions were tiny, but required welding parts together and were thus awkward. The current 20210607 version instead uses a screw thread for assembly; the thread is a bit touchy/sticky, but it's still better than welding.*The 20210607 design does mount on most Sony E bodies other than the A3000, but is a VERY tight fit going on to an A6500 or A7II, so expect a revised design to be posted here shortly.* Print Settings Printer Brand: Anycubic Printer: Kossel Rafts: No Supports: No Resolution: .25 or finer Infill: 15-40% Filament: Any PLA or ABS Any light-blocking colors Notes: These are precision parts, so pick appropriate settings for your printer. However, there is nothing tricky about printing them. The touchiest part by far is the set screw, which is a 1/4-20 thread part with a screwdriver slot; it is used to lock the M adapter in place. The screw is potentially subject to deformation over time and use, so you might want to print a spare or two. It is strongly recommended that the E and M mount parts be made of opaque material to prevent stray light leaking in. However, that is much less of an issue for the screw and especially the ring, which worked fine printed in white PLA -- so feel free to pick a fun color. Using APSC2 The APSC2 parts need to be assembled for use -- an exploded view has been added to assist you in doing that. Insert the M part inside the ring such that all four 1/2-20 screw holes are visible. Next, screw the E part into the ring. It should be screwed-in enough to be tightly against the M part. There will be some friction in turning the M part, but that's actually helpful once everything has been mounted. To use APSC2, you'll need a suitable lens. For the photo shown here, I used a Canon FD mount Vivitar 135mm f/2.8 with a commercial FD-to-M adapter. I picked it because it has a rendering somewhat reminiscent of medium/large-format lenses, but most lenses should work. Some lenses and adapters have a "tripod foot" for mounting, but this one didn't, so I used Parametric Lens Mount Ring to print one. There are lots available commercially for under $25, but lens diameters vary, and this was easy to customtize for a good fit on my Vivitar. To mount a lens on APSC2, start by turning the M part of APSC2 until you see a 1/4-20 hole all the way through to the right of where the APSC2 text is. That hole serves as the mounting alignment mark for your M-mount lens or M adapter; line it up and push your M lens/adapter onto APSC2. Turn the lens/adapter clockwise to line-up the locking slot with the center of the 1/4-20 hole. Now take the set screw and use a screwdriver to screw it into the 1/4-20 hole so that the tip locks in the locking slot. This is a bit more robust locking method than is normally used, but we don't want the rotation of the camera to unmount the lens.... Once the set screw is in, you can mount your lens on the M adapter (if it wasn't a native M lens already mounted) and the camera on the E part. There isn't an alignment mark per se, but it's pretty obvious how it goes together and the E-mount lock should engage when it's on properly. Connect the lens/adapter tripod foot to your tripod.Although the design tries to ensure things will stay firmly connected, we cannot promise that your camera and lens will stay firmly connected as you rotate the camera -- so use this at your own risk and be very careful! Fortunately, most APS-C Sony E-mount bodies are fairly lightweight, which helps. Earlier versions of APSC2 (20210523 and 20210525) had little spring-loaded "bumps" that would give some tactile feel for each of the 90-degree rotational positions, but that proved less accurate than simply using your Sony's virtual horizon electronic level. Thus, the procedure is simply to line-up the camera and then capture at least one image each for the camera horizontal, vertical left, upside down, and vertical right. Arguably, it would be best to fix the exposure for these four shots or to shoot an exposure-bracket sequence in each orientation, but good stitching software can work despite modest exposure differences. For stitching, I recommend Hugin. It's free, runs on most computers, and produces very high-quality results. The key trick to know is that, unlike stitching a sequence of photos taken by moving the camera and lens, your images shouldn't really have any lens motion. Thus, you'll want to tell Hugin that you used a lens with a relatively long focal length, so that it doesn't try to undistort captures that were not distorted in the first place. For example, I find 5 degree view angle an effective lie. Keep in mind that the stitched images will vary slightly in pixel count and even in aspect ratio due to minor misalignments. I recommend letting Hugin pick the render resolution and then cropping and (down) scaling to the appropriate square image: stitching four 6000x4000 images from my NEX-7 nominally produces a 7648x7648 result (approximately 30x30mm at camera native pixel pitch). In fact, the overlaps mean that Hugin could do a bit of HDR, super-resolution, and/or noise reduction processing, so each pixel should be of slightly higher quality than a single shot delivers -- provided nothing has moved between captures. The last three images posted here are scaled-down stitch results. The image just before those is one of the component image captures. Category: Camera