Steaphany
Well-Known Member
Other than a few tight spots, there was no kicking or screaming.
I'm sure those who follow my posts have realized, I have a rather diverse range of technical and non-technical interests, well here is another one - pinhole photography.
As the earliest known image focusing element, dating back to the 4th century BC, imaging through a pinhole provides both challenges and opportunities. A pinhole has no focus and it's depth of field is infinite. If objects in the field of view are 25mm, 30cm, 10m, and 1km from the camera, they will all be equally focused. The effective aperture is fixed and very small, resulting in long exposures. You can't freeze moving objects and even for static subjects, a tripod is essential. For digital imaging systems, where dust on an imager causes headaches for modern optics, dust can be a thorn when shooting through a pinhole. The image quality has an unique softness lacking fine detail, perfect to add just a little more when striving for an antique look and feel to a photo. For anyone interested in learning more about the specifics, Wikipedia has a good page on pinhole photography:
Since the only commercially available photographic pinholes for SLR cameras, that I found, are the pinhole elements glued the a camera manufacturer's body cap, I decided to assemble my own. For my telescope, I already have a T-Mount adapter, so it was an easy step to go to one of my optical component suppliers and buy the needed parts. This is the result:
The lens mount along with the T-Mount adapter has a pinhole to focal plane distance of 52.8mm. I calculated the optimum pinhole to be 320um and the closest size that I could buy off the shelf was 300um. The aperture turns out to be f176. The field of view is equivalent to a 52.8mm lens, 22.18° Horizontal by 14.89° Vertical. This configuration provides a tighter view than what is more typical of pinhole images and the dimensions of the Foveon imager results in none on the expected vignetting.
Here is the results from an .5 Second exposure at ISO 100 that I shot the other morning of my house:
One thing you may note, little to no imager dust! Right after shooting this image, I also shot a flat frame and ran the two through DeepSkyStacker. Since such details would be off topic, I will be making an extensive post to the Digital Darkroom going into every step of the process.
For a final antiqued image, this is the original X3F file, with imager dust included, after being processed through Silver Efex Pro:
I'm sure those who follow my posts have realized, I have a rather diverse range of technical and non-technical interests, well here is another one - pinhole photography.
As the earliest known image focusing element, dating back to the 4th century BC, imaging through a pinhole provides both challenges and opportunities. A pinhole has no focus and it's depth of field is infinite. If objects in the field of view are 25mm, 30cm, 10m, and 1km from the camera, they will all be equally focused. The effective aperture is fixed and very small, resulting in long exposures. You can't freeze moving objects and even for static subjects, a tripod is essential. For digital imaging systems, where dust on an imager causes headaches for modern optics, dust can be a thorn when shooting through a pinhole. The image quality has an unique softness lacking fine detail, perfect to add just a little more when striving for an antique look and feel to a photo. For anyone interested in learning more about the specifics, Wikipedia has a good page on pinhole photography:
Since the only commercially available photographic pinholes for SLR cameras, that I found, are the pinhole elements glued the a camera manufacturer's body cap, I decided to assemble my own. For my telescope, I already have a T-Mount adapter, so it was an easy step to go to one of my optical component suppliers and buy the needed parts. This is the result:
The lens mount along with the T-Mount adapter has a pinhole to focal plane distance of 52.8mm. I calculated the optimum pinhole to be 320um and the closest size that I could buy off the shelf was 300um. The aperture turns out to be f176. The field of view is equivalent to a 52.8mm lens, 22.18° Horizontal by 14.89° Vertical. This configuration provides a tighter view than what is more typical of pinhole images and the dimensions of the Foveon imager results in none on the expected vignetting.
Here is the results from an .5 Second exposure at ISO 100 that I shot the other morning of my house:
One thing you may note, little to no imager dust! Right after shooting this image, I also shot a flat frame and ran the two through DeepSkyStacker. Since such details would be off topic, I will be making an extensive post to the Digital Darkroom going into every step of the process.
For a final antiqued image, this is the original X3F file, with imager dust included, after being processed through Silver Efex Pro:
