It is not easy to obtain such a sensor [Yannick] haven’t even tried it. The hack starts by taking down some recent Kodak scanners from eBay to get to those fancy CCD line sensors. Yes, this is that classic hack: the scanner camera. Then we’ll get to work with the oscilloscope and the datasheet for some serious reverse engineering to figure out how to talk to these things. The protocol analysis starts about 4 minutes into the embedded video and is worth watching even if you have no interest in photography.
As for what the line sensor will talk to, it’s nothing more than a Rasberry Pi 5, which communicates via a custom PCB that also contains the stepper motor. Please note that this is a line sensor camera: the sensor must be scanned line by line across the image plane in the camera, just as it is in the scanner. He uses ready-made linear rails to do that work. Technically we suppose you could use a mirror to optically scan the image over a fixed sensor, but scanner cameras traditionally did it this way and [Yannick] adheres to tradition. Why not? It works.
Since these images are going to be enormous an SD card in the Pi is not enough, so this may be the only camera with an NVMe SSD. The raw data would be 19 GB per image, and even though he post-processed to PNG, they are still large images. There probably aren’t many cameras with 8-inch touchscreens either, but since the back of the thing is so big, why not? There is also still a CSI camera in it, but in this case it is used as a digital viewfinder. (Most of us would have made that the camera.) Of course, the scanner camera is far too slow to generate its own samples. The preview camera is actually placed on the same 3D printed mount as the line sensor, placing it on the same focal plane as the sensor. Yes, the real-time previews are used to focus the camera.
In many ways this is the nicest scanner camera we’ve ever owned, but that’s perhaps to be expected: there have been many innovations to facilitate this build since scanner cams were common. Even the 3D printed aluminum housing looks professional. Of course, a big sensor needs a big lens, and after deciding that projector lenses wouldn’t be enough, [Yannick] developed for Pantax 6×7 system lenses, which are made for medium format cameras like this one. Well, not exactly like this one: These lenses were first made for film cameras in the 1960s. Yet they offer a huge image, high-quality optics, and manual focus and aperture controls in a format that could easily 3D print a mount.
Is it the most practical camera? Maybe not. Is it an impressive hack? Yes. We’ve always had a soft spot for scanner cameras, and in a recent dual CCD camera hack we lamented in the comments that no one was doing it anymore. So we are very grateful for that [Manawyrm] before submitting the tip.
#Medium #format #GigaPixel #camera #puts #line #sensor