3D-printed Digital Camera Obscuras

Well, it's finally out: my rather long 3D-printed Digital Camera Obscuras Instructable, with all the part designs posted as STLs at Printables. Faboky is the result of a little project that grew out of a discussion in our very own Adapted Lens Forum.

For photography, bigger formats are better, right? Well, in most ways they are, provided the camera parts fit within the build volume of a typical consumer 3D printer. These obscuras cram a 180mm diagonal screen into a 3D-printed housing so you can use a digital camera with a tiny sensor to make photos that look like they were made with camera format about 20% larger than 4x5" -- FF is a crop factor of about 4.16X smaller.

Faboky (fah-bow-key) originally stood for Fresnel Apodized Bokeh Obscura from KentuckY. As it turned out, Flexibly Adaptable Bokeh Obscura from KentuckY is a better definition because it can be used without apodization, with conventional lenses instead of Fresnel, and even with pinholes. For digital capture, you can either use a cell phone or compact camera -- and I've posted an HDR multi-shot capture script to run inside Canon PowerShots supported by CHDK .

So, here's how it works:

Faboky with a Samsung S20 Ultra capturing a FF-equivalent view of 32mm f/0.53

Here's the shot captured above (using a Logetar 135mm f/2.2 on Faboky)

That's not exactly a crisp image -- no ultra-fast lenses produce really sharp images wide open, in large part due to poor correction of spherical aberration. Depending on choice of screen material, you could get up to about 6MP resolution with a good lens intended for 4x5, but the ultra-fast Logetar and the Fresnel lenses aren't anywhere near that good, and even 1MP is tough with the Fresnel lenses. Then again, it's hard to find f/0.5 full frame lenses at all, and the 3-element Fresnel version of Faboky is equivalent to an optically very disappointing 23mm f/0.13!

There are literally hundreds of reasonable configurations of Faboky, with typical build cost under $25. They are pretty big, but most weigh no more than "about half a Noct" -- i.e., about 1000g. Except for the pinhole versions, they can be shot handheld.

Here are the basic variants.

Single-element 290mm f/1.6 Fresnel lens and ELPH 160 -- 70mm f/0.4 equivalent

3-element 97mm f/0.53 Fresnel lens and ELPH 180 -- the disappointing 23mm f/0.13

Conventional 4x5 lens and ELPH 180 (shown with Logetar 135mm f/2.2)

Homemade pinhole and Canon PowerShot ELPH 180

Read the Instructable for details... and enjoy Faboky's blurry goodness! Or maybe just use it with good lenses designed for 4x5 to get much higher resolution? After all, a very ordinary 135mm f/4.5 lens intended for a 4x5 enlarger delivers the full-frame equivalent of a decently sharp 32mm f/1.1...

fferreres wrote:

Hank, I had missed this post and stumbled upon it by chance, that I almost missed it forever. From the pics, I gather one can print a longer tube to accommodate longer FLs.

Yes, and there are a wide selection of different size STLs posted. You have some flexibility because they all use a large screw thread to allow focusing.

One thing I immediately notice with my experiments is that most fresnels sold as magnifiers are really very low in quality.

Yup. I was shocked that stacking 'em worked at all, but 2 or 3 elements still worked to reduce the focal length. They never produce a sharp image.

I'd LOVE to see a version with a rear reverse 49mm or 55mm ring. This could allow mounting any kind of lens and camera.

Ah, but the focus distance for the digital camera would vary then too... so there would be another screw thread and two-part arrangement. It doesn't matter. Running with CHDK (and a script like the one I posted), a cheap PowerShot easily gets all the IQ this can deliver.

I will now head to the Indestructible, and realize how little I understand and much unprepared to make it, and how much I wished I could give 4x the $25 to have one printed and shipped my way

Faboky is an easy set of prints, but it is something like 24 hours of print time for a typical configuration. That probably means it would be expensive through typical 3D printing services, although it's cheap to print yourself.

A camera is not complete until there are amazing samples of pictures, so it's up to us fans of the optically strange to do our part.

Honestly, I haven't gotten any photos from it that I consider really compelling. However, it does easily produce images that look like they came from a large-format camera, so mission accomplished.

I think it rocks when one can have a professor do all crazy things on their own time, just for the love of everything photographic. You are really cool!

Well, most of what I do is stuff I love doing... that's why I'm OK with making a salary now as a tenured, chaired, professor that's a little less than half the lowest salary offer I had from industry four decades ago.

BTW, I also did end up having something spin off from this that I'm trying to publish as a scholarly work -- it's mostly a study of obscura screen properties, both rear and front projection. Incidentally, the Fresnel+ground glass shots you have here look really good; they have more texture and Fresnel artifacting, but my favorite rather opaque screen material tends to diffuse so much that it limits resolution and gets quite dark. BTW, Faboky does have the ability to mount a ground glass, on the inside of the middle rather than sandwiched between middle and back, but that doesn't really seem to be worthwhile over some other screen materials I've tested.

I think we've got a lot of folks in the forums here (including you) who are obviously inspired to put ridiculous levels of effort into playing with cameras and lenses and informing the community. I'm not so sure I'm all that far from the norm here.

fferreres wrote:

ProfHankD wrote:

Faboky is an easy set of prints, but it is something like 24 hours of print time for a typical configuration. That probably means it would be expensive through typical 3D printing services, although it's cheap to print yourself.

is there any printer that you recommend to an absolute new-by without much time to invest in this, as close as an toaster as possible?

Well, my personal favorite is the AnyCubic Linear Plus, which is a $180 Kossel/Delta-type printer... that they don't make anymore.

AnyCubic's new Kobra Go is quite different, but is currently $189 and actually looks like it should be even more functional. It handles a build volume of 220x220x250mm, which should be able to make all the Faboky parts except those options longer than 250mm. AnyCubic seems to put a lot into design of their printers; they're feature-packed, rigid enough, and they'll put money into tooling (e.g., injection molding parts) to keep precision high and cost low.

... I think the screen needs to matte only in a very thin plane.

I agree. Ideally, a rear-projection screen should highly diffuse and very thin. Ground glass is a thin enough diffuser, but not a very good diffuser. The screen I'm using is a great diffuser, but thick enough to scatter light internally too, cutting sharpness.