DPR Forum

Welcome to the Friendly Aisles!
DPRF is a photography forum with people from all over the world freely sharing their knowledge and love of photography. Everybody is welcome, from beginners to the experienced professional. Whether it is Medium Format, fullframe, APS-C, MFT or smaller formats. Digital or film. DPRF is a forum for everybody and for every format.
Enjoy this modern, easy to use software. Look also at our Reviews & Gallery!

Dragging a SD14 through a Pin Hole

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:

Pinhole camera From Wikipedia

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:

View attachment 1428

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:

View attachment 1426

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:

View attachment 1427
 

Attachments

  • Autosave00716s.jpg
    EXIF
    Autosave00716s.jpg
    294.7 KB · Views: 14
  • SDIM5186sfxs.jpg
    EXIF
    SDIM5186sfxs.jpg
    290.8 KB · Views: 14
  • IMG_0520s.jpg
    EXIF
    IMG_0520s.jpg
    113.4 KB · Views: 11
Hi Steaphany,
very interesting experiment you did.
Thank you for sharing.
I´ve gone to the ref.link on wiki,looks interesting too.
Regards
Uwe
 
Awesome Steaphany...
I always thought pinholes gave really wide angle views.
I was wondering if you left the IR cut filter on but I'll check your other post.
Thanks for sharing and world pinhole day is close! You should submit your Sigma pics.
 
Akv,

Pinholes can have a wide view, but that's dependent on the size of the film or imager and the distance between the film/imager surface and the pinhole.

Yes, I kept the IR blocking filter on.

Another point to mention, since a pinhole leaves a opening from the environment to the interior of the camera body, I also added a glass anti reflection coated optical window infront of the pinhole.

Yes, I was planning on submitting a SD14 digital pinhole image to the world pinhole day web site.
 
Steaphany,

Is there an optimum distance between pinhole to the sensor or is there some degree of tolerance?

I used to make pinhole cameras out of cylindrical oatmeal boxes. The curved film inside the can all stayed pretty well in focus in spite of the edges being at a different focal length than the center (resulting in a super-wide angle effect).

Jesse
 
Steaphany...thanks again...for the showing us the shot and explaining how you do it....love the work...

Tony C.
 
Jesse,

Check out the Wikipedia link I listed earlier in this thread. The wiki page gives the formula for the optimum relationship between pinhole diameter and the pinhole to image surface distance.

For a given distance, 52.8mm in my configuration, there is a pinhole diameter which provides the best trade off between a clear and focused image and minimal diffraction induced artifacts. Another factor that is part of this balancing act is the formula is the wavelength of light, where I chose 550nm corresponding to Green and near the center of the spectrum.

For anyone who wants to try their hand at pinhole photography with a SD14, here are the components:

NT56-285 300um Aperture Dia, Precision Pinhole, Mounted

NT52-292 T-Mount 25/25.4mm Thin Lens Mount

NT46-098 Window 1" Dia. 3mm Thickness, AR Coating

If you don't have a Spanner Wrench to properly assembly the pinhole and window in the lens mount, I used this:

NT36-413 Mini Spanner Wrench Set

Just remember that you will also need to have a T-Mount adapter to attach this pinhole to your SA mount.
 
Steaphany,

Thanks for showing how this was accomplished, also, I enjoy looking at the photo that is antiqued. It really has quite a bit of originality to it!!

I look forward to seeing the subjects that you will shot in the future with this setup.

Good luck with your pinhole camera,

Robert
 
Back
Top