Holga-rific tilt-shift mechanism
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What size are the threads on lens filters?
Specifically, what is the thread pitch on 58mm filters?
I’m guessing it’s 1 mm, but I’d like some confirmation.
The reason I ask is that I’m drafting up a design for a cheap tilt-shift mechanism that could be produced with a 3D printer. I expect it to be Holga-rific (or perhaps Loma-licious)!
edit: changed thread title.
Standard pitch is 0.75 (except on some tiny or huge ones): http://www.schneideroptics.com/info/faq/bw.htm#q31
Thanks. It’s a good thing I’ve got a parametric model.
In case anyone is wondering, http://www.shapeways.com/ is the manufacturer I’ve been looking at for this project. Some of their customers have already created camera stuff like a M42 lens adapter, ring light, and tripod quick release mounts.
Unlike the super-cheap flexible bellows or duct tape DIY versions that offer no stability, my design is based on rotating couplings that are angled (for tilt) and offset (for shift) from the central film plane axis. By printing calibrated scales and gluing them around the barrels, I’ll be able to know exactly how much I’m tilting or shifting. The current design is for 10 degree tilt and 12mm shift. Slap a +10 diopter on the front end for 100mm focal length or add a +4 on top of that to bring it down to 71mm. The ultimate focal length really will depend on how compact I can make the model from front to rear plus the 44mm flange to sensor distance. Should cost a lot less that the $1,300 Canon wants for the TS-E 90mm and most likely less than a Lensbaby kit.
My next question is where to put the aperture stop plate? Should it go up front right behind the lens to ensure concentricity?
Wow. Can I buy stock? That is so incredibly cool! Lithography for the common folk!
As for you specs, I don’t speak Spec. But it sounds like a cool project!
One more question. By any chance, does anyone know the angular specifications for the bayonnette mount for EF lenses?
I reverse engineered my Holga EF 60mm f/8, but it would be nice to have a second source before I plunk down $17 for the first part alone.
http://shpws.me/and9
I’ll update this when I get all the parts uploaded. Suggestions for improvement are welcome.
Yoyo, I tried following your link but:
“This host was blocked by OpenDNS in response to the Conficker virus, the Microsoft IE zero-day vulnerability, an equally serious vulnerability, or some other threat.
If you think this shouldn’t be blocked, please email us at malware-block@opendns.com.”
I’m thinking if you had a better browser, you would get a more descriptive and accurate error message, like the certificate is registered to a different domain name… I took that bet since it looked good, and I’m accustomed to dealing with bigger organizations that you would think would have their act together but they don’t. /cough/ US Army /cough/.
Anyway, the price adds up quickly, so I’m going to hold off for now while I fine tune the design and shop around for other rapid prototype facilities.
One of the bits of fine tuning would be to get the angular locations of the beginnings and ends of the 3 bayonette flanges. I’ve already figured out that the red dot is at 10:00 and the lock pin notch is at 9:00. I suspect the top flange starts at 10:30 (45 deg) and ends at 12:20 (5 deg), and that’s where I put the centers of the fillets.
The ISP at my house uses open DNS, I’m thinking that (and not the browser) is the source of error as I tried it just now at work and got through just fine. To what accuracy do you need the data? I have Canon gear and can make measurements in a machine shop it if it will help.
+/- 1 degree should be close enough. Now that you mention it, I could probably dig up a pair of calipers and measure the distances myself to get the relative location of the flanges. For distances, +/-0.05 mm. The laser sintering process generally has a tolerance of +/-0.1 mm which is on par with the data I’ve seen for other 3D printing processes.
Hey Yoyo. I didn’t have time to go to the shop tonight but I found this:
http://www.truetex.com/topcon-fundus.dwf
There are numerous DWF -> DWG converters out there that should handle it (Any DWF to DWG Converter is one).
Found this at:
http://community.the-digital-picture.com/showthread.php?t=817
I’ve got that file as well, and it’s good with the free Autodesk DWF reader, but I can’t figure out how to get the measurement tool to give me the angles. Also, that file has the flanges evenly spaced at 60 degrees all around, and I know that’s incorrect because Canon lenses will only fit on in the proper orientation.
Understood, will try to make some measurements tonight.
Also, if anyone has the dimensions for Nikon, I could model one of those as well. I’ll need the flange to film distance too. I could even shrink down the model to match the 52mm threads on the Nikon entry level lenses, and this should reduce the cost by up to 12%. No guarantees about performance.
One more question. By any chance, does anyone know the angular specifications for the bayonnette mount for EF lenses?
Hey Yoyo,
Sorry for the delay, stupid real life etc,…
Hopefully I have interpreted your request correctly, if not let me know.
These measurements were aligned visually which should meet your 1 degree tolerance.
Starting with the white registration mark at 0 degrees:
28.36 deg:
73.31 deg (first electrical contact):
90.00 deg:
157.19 deg:
212.42 deg:
272.58 deg:
325.47 deg:
You left out the locking pin slot that is about 10 degrees past the white mark. Furthermore, I’m modelling this with the red dot (and maybe the strip too 🙂 ), and the red dot seems to be 30 degrees off of the dentent. That 30 degrees would yield a 60 degree rotation from the dot being up to the pin being at the side. It seems your numbers are quite different from mine. My measurements from the top flange (as installed) (proceeding clockwise) (looking at the back of the lens) are 50 degrees wide, 65 (space), 50, 70, 60, 65.
Oh, Fark all that. Here’s an image of the model sketch.
The red dot and pin slot are visible at 10:00 and 9:00 in this view.
The flanges are at 11:00, 3:00, and 7:00, with the cut outs between them. (The grey lines are the edges.)
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