/diy/ - Do It Yourself

>>1719340
2 things slide. The "tube" slides to change the focal length and the metal strip with pinholes slides back and forth to change when the focal length is changed. I have a bag with several slider strips I can use. I don't use them much though. I much prefer fixed pinholes like this one.

>>1407609
Based on the previous "Mark I" invasive pinhole cap, I decided to max out the pinhole focal length for my camera. I used a paper cardstock cone and kept cutting it down until it reached 20mm focal length. Any shorter focal length and I was seeing parts of the inside of the camera and running out of image diameter on the sensor. The only problem with this pinhole is the incoming light, on the edges of the sensor glass is as such a sharp angle it is causing a red-pink-purple hue on the extreme edges of the images. It also suffers from vignetting as well. I used aluminum sheet metal for the pinhole material.

Focal Length: 20mm (30mm equivalent on 1.5x crop)
F-stop: f/106
Optimal Pinhole Diameter: 0.1888mm
Actual Pinhole diameter: 0.1708 (error of 0.018mm; best for 16.4mm FL)

Image Diameter: 38.4mm (D3400 APS-C requires 28.21mm+)
Invasive into Camera Body to: 23mm
Angle of View: 42.6 (on 1.5x crop)
Sunny Day Exposure: 1/2 second at ISO 100