Kraken 6x12 3d printed panoramic camera

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shawn

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Being quarantined, yet again, I spent most of the afternoon working on this. The compur shutter had to be cleaned, low speeds were sticking. Then the rest was basically assembling the parts I printed during the week. You need a build plate of 210x210 at least. Still have to print the finder.

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The design is nicely done and everything goes together easily. The designer is really quick to answer any questions. The most annoying part was really just getting the lens board into the helicoid.

It went together as the sun was setting so I couldn't really calibrate the focus yet. Just checking indoors I think I need to print a shorter lens cone as this seems to be focusing about 12' out with the helicoid all the way in. I did a "70mm" cone, will print a 69mm cone next and then shim it as needed to hit infinity properly. The design even has shims in it to go between the lens cone and the body and also between the helicoid and the cone.

Plans are $30 at http://frozenphoton.com/kraken/

The helicoid is $22.
Bolts were about $6
$5 or $10 in PLA
already had glue and paint
and then the cost of a lens that will cover a 120mm image circle.

Might be able to use a shutter/lens off a dead 116 camera for a really inexpensive option. I have a Monitor 116 with a dead baffle I might try on this.

After I get the focus calibrated I will put a roll through it.

Shawn
 
Nice.

You can calibrate the infinity focus inside. All you need is a piece of unexposed and developed film, a piece of film-sized glass and an SLR with slit-prism. See here: http://feuerbacher.net/photo/repair/InfinityFocus/InfinityFocus.html

You can also make a focus scale with arbitrary distance markings, as long as you've found the infinity point. A bit of math is needed but happy to share the info.
 
Thanks everyone, I'm looking forward to trying it out too.

Also thanks for the link on calibrating focus indoors. That looks easy enough, I will try that tomorrow. 1mm shorter cone is printing now.

Would love to know the info on the focus scale too. Not sure how I'm going to mark that yet but was thinking about doing it on the lens board and putting a pointer on the helicoid dial.

Shawn
 
Ok so the lens movement x from infinity position to focused at distance D is x= f*f/(D - 2*f), focal length = f. All in mm.

Given a helicoid pitch P (those generic helicoids are 24mm per turn), then the angle to get to D is a = 2*pi*x/P.

Given the diameter d of where you're putting the scale, the position of distance D is at l = a*d/2 from infinity mark.

You can draw the scale on a piece of paper (or find a way to generate on a computer and print 1:1), then stick it on.


edit: the formula for x is approximate but should hold up well up to 1m for symmetrical-ish lenses
 
Thanks for the math, will work through that in a bit.

I ended up printing several different cones. I think the 67mm has me pretty close to infinity with the helicoid all the way in. Just using scotch tape, my 6x9 ground glass hasn't arrived yet. I tried the indoor infinity trick with my F2 but the split image was going dark. Used my Sony mirrorless and zooming in which seemed to work well. I will probably recheck when the ground glass arrives.

I realized my FUJIFILM VF-X21 is pretty close for framing. The 21mm framelines give me the width and the 28mm framelines are the height. The lens does get in the bottom of the VF so I might print an extension to raise it up a little. On the flip side I could glue a small rectangular bubble level for the horizon on the lens cone and it is visible through the viewfinder. Other possibility is printing a mask for a larger Avenon 21mm viewfinder.

Couple more camera pics along with a GSW690 to give scale. A little wider, not as deep or as tall and much lighter.

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Took it for a walk and put a roll of Fomapan 100 through it. Plastic body is *really* nice to hold in the cold. I had one accidental double exposure (I knew it as soon as I took the shot) but other than that it worked fine.

Film is drying now. These are just shot with it hanging so the curved sides are from the film bending.

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When it dries I'll scan it to see how well it did. But these are encouraging!

Shawn
 
I like to make the cones a little short you can can nail the infinity position from both sides. Also, you can use a flashlight or lamp behind the camera for the "infinity indoors" trick.

And you can make you own ground glass with silicon carbide powder... takes about 5 minutes of elbow grease.
 
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What is the diameter of the helicoid? How do you secure it to the cone? Does it come with a retaining ring?
I keeping looking at 58mm helicoids but have no idea of how they are retained to a lens board.
 
The helicoid is a M65 17-31mm. It has a male thread and screws into the lens cone. The lerns board threads into the female threads on the other side of the helicoid. The shutter is help in place with a retaining ring.

Shawn
 
I have a Kodak Monitor 616 with a dead baffle that I am working on adapting its lens/shutter and viewfinder to the Kraken. The 127mm f4.5 Anastigmat Special is front cell, scale focusing already so once I get the cone length proper it already has the focus scale on it and won't need an external helicoid. This will make for a very light 6x12 panoramic camera that is also really inexpensive. Vertical FOV should be roughly the same as a 55mm lens on 35mm. This cone has infinity at about the 25' marking. Printing a 2mm longer cone now and will shim the cone and shutter if needed to nail infinity.

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Also planing on designing an adapter to make the Monitors pop up viewfinder fit into one of the cold shoes on the camera body. 616 is 1.7:1 AR so with a touch of vertical masking it should do well on the Kraken. The lens is covering the entire film gate but I won't know about vignetting till I run some film through it.

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Shawn
 
Had a couple of bad prints on my second body but got that squared away. This used a Monitor Six-16 as a donor.

This is all done now. With the 127mm f4.5 lens I get about the same vertical FOV as a 53mm on 35mm and around a 38mm horizontally.

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I set the lens cone length so that the focus scale on the shutter is accurate. No need for an external helicoid on this body. I printed an adapter for the Monitor's viewfinder which should be pretty close, even has parallax correction. I also printed a different lens board sized for the Kodak shutter and reduced its overall size to match the lens cone better.


Between the two I have a wide angle and normal FOV.

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Considering their size it is crazy how little these weigh. The 65mm one is about 1.948 pounds (with accessories), the 127mm version is 1.6 pounds. My M3 with a Konica 50mm is 1.98 pounds.

Now if the weather would just clear up....

Shawn
 
Test roll from the KodaKraken. Focus is good.

Wide open at 6' away: (f4.5, 1/10)

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F4.5 1/25

Fomapan 100 in HC110 100:1 for 60 minutes

Shawn
 
I adjusted the winding on one of the cameras and made it a bit too loose. The film wound uneven on the take up spool and fogged itself a bit. Just tightened it up and it is good now.

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All KodaKraken with Fomapan 100

Shawn
 
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