smarter than anybody

Small cars, downtown San Francisco.

Of note - the photos were taken with Bendycam, the newest DIY tilt-shift lens in my stable of strange optical devices:

Tutorial and other goodies coming soon.

The fisheye tin cam

[You can find other DIY photography projects here]
[Also I'd like to shout out to the good folks at Photojojo - if you like photo goodies, I'd recommend perusing their catalog of awesome. ^*]

Fisheye lenses are insanely fun to shoot with. They allow you to shoot at very wide angles - wide enough lenses will get people standing right next to you into the shot. I've always loved the wide angle look in videos, and I thought it'd be an awesome exercise in redundant and needless hackery to build my own.

Here's the gloriously ugly result:

Built using a fisheye peephole as the main lens element and a decapitated soda can as the lens body (!), this attaches directly to my SLR camera. For well under US$20, I ended up with a lens that has nearly a 180-degree field-of-view, adjustable focus, a canon EOS mount, and due to it's stylish and sleek exterior, can generate limitless amounts of admiration ridicule confusion. Unlike commonly (and cheaply) available fisheye adapters, this build does not attach to the front of an existing lens - it's a completely self-contained unit that doesn't require any other optics to work.

Step 1: Research!

The cheapest and easiest to get fisheye lens out there at the moment is the garden variety door peephole lens. These simple optical devices can be picked up cheaply at your local hardware store. I picked up mine for US$6; it offered a huge field of view (nearly 180 degrees).

As I discovered in my previous hacks, individual lenses are hard to directly transplant from one device to another. Often an intermediate lens is required to refocus the image so it hits the sensor/film correctly. The peephole lens couldn't be used directly with the SLR - like the phone-o-scope, it needed a teleconverter is needed to magnify the small image at the end of the fisheye barrel, and bring it into focus at the image sensor.

A number of good tutorials have gone over the method of using an existing, standard lens as a teleconverter. That's where I started:

First attempt

...and while this works, I didn't like the idea of having a complex lens in-between the fisheye and the camera. Modern lenses have many internal elements, each one dimming the image coming from the fisheye and leading to low-contrast images. I wanted to build a lens that would remove the complex in-between lens and replace it with a simple one that wouldn't lose quite as much light.

Step 2: Testing

I needed to couple the fisheye lens with something that would magnify the image coming out of it, and space it so that it would form a good image at the sensor. Rummaging around in my parts box, I found an old, single element projector lens that came from an old 35mm slide projector. These are pretty pretty easy to find, and I've seen them a lot at garage sales.

Left: projector lens, right: fisheye lens

I took the body cap off my camera, and held the two lenses in front of the body. Looking through the viewfinder and experimenting with the lens positions, I was able to come up with an estimate for how far the lenses needed to be apart from each other and the camera body to make a reasonable image. Running around loosely holding lenses in front of the camera tends to be fraught with danger, however, so the next step was to build a permanent enclosure for them.

Step 3: Design

The materials list for the design:

• Projector lens (US$3, second-hand)


• Door peephole lens (US$6, new from the hardware store)


• T-mount to EOS adapter (US$9 new from eBay, but you can use a drilled out body cap instead which would be ~US$4)


• Soda can (US$1)


• Packing foam (US$0)


• Cardboard stopper rings (US$0)


• Plumbing clip (US$0.5)

The design centres around having two main components - a lower enclosure for holding the projector lens, and an upper slot for the fisheye lens.

In the design, the lens attaches to the camera using a T-mount to EOS adapter. It turns out that the adapter I was using had nearly exactly the same diameter as a soda can, so I decided to use that as my lens body. To hold the projector lens firmly in place in the can, I made use of two pieces of packing foam, cut into halves of a cylindrical tube that fit around the projector lens. Since the foam I was using is not completely opaque, I also inserted a cardboard ring cut into the shape of a donut at the base of the foam cylinder to stop light leaks.

A similar principle is used to fit the fisheye lens into the projector lens mouth. Foam discs that are a little larger than the diameter of the projector lens mouth are cut out; in the centre of this a hole is made so that the fisheye lens fits snugly inside them. Another cardboard stopper is placed at the base of the foam to stop light leaks.

Step 4: Building the tin cam

Actual assembly

Assembly was pretty straightforward. The t-mount is inserted into the can first, and the stopper ring on top of it. The foam cylinder halves are inserted next. To keep things extra secure, a plumbing clip is wrapped around the mount end of the can. The projector lens was carefully inserted into the centre of the foam cylinder tube. The projector lens that I had has a screw-thread, so I was able easily twist it into place. This added an extra bonus - turning the projector lens unscrews it, allowing for racking the lens back and forth - which means that the lens can be adjusted for focus.

Most door fisheye lenses come in two parts - a lower part which goes into the back of the door, and an upper part which screws into it from the front side of the door. Separating the lens into these two halves, the cardboard stopper is slid it on to the lower half. The foam discs are slid on next, and then the top half of the fisheye is screwed back in. This whole assembly is snugly fitted into the mouth of the projector lens, and then the build is complete!

Final build

Even if your projector lens doesn't have a thread, you can still adjust the focus by turning the upper half of the fisheye lens - unscrewing it a little with lengthen the lens body, allowing you to finely focus it.

Step 5: Going nuts

woof!

The fisheye lens is ludicrously fun to shoot with. If you can, get in close to your subject - you'll be surprised how close you can get and still have your surroundings in the frame. Pets are always awesome for fisheye photos, especially if they're happy to stick their nose into the lens.

Mission District

The lens combination makes saturated, contrasty pictures. As the results show, door fisheye lenses were never meant for even vaguely serious photography, and individual images don't stand up well to close inspection. In future revisions I think I might experiment with adding in an aperture to crank up the f-stop and perhaps reduce some of the sharpness and colour artefacts.

However, if you take a few of the fisheye pictures and arrange them into a grid, you can use them to tell a story or paint a picture of a place with a few images. In all of these shots I've cropped the images to squares, and then used a circle mask to get a clean circular crop around the edges of the pictures.

Potrero Hill Portraits

Go nuts with it, and get in close - I don't think you'll be disappointed :) You can find other fisheye tin-cam photos on flickr here.

fffffff-isheye!

^*I keep this site free-as-in-beer, but shopping on the photojojo site via this link contributes in a small way to my needless-optics-gear-fund and makes for a very happy photo nerd.

Plungercam 2: cheaper and more predictable :)

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New visitors: the updated DIY tilt-shift lens tutorial is here: http://cow.mooh.org/projects/tiltshift.

In it, I've got a comprehensive guide to how tilt-shift works, along with a guide to using existing 35mm lenses to build DIY tilt-shift lenses.

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[Edit #0: hi to everyone from hackaday, crunchgear, makezine, lifehacker, and wired! And Photojojo too :)]

[Edit #1: Some new results with Plungercam 2 here; earlier video experiments with tilt-shift here and here.]

[Edit #2: Those who are looking for the reasoning behind the project and details on how to get parts might want to check out the write up for the original plungercam first.]

[Edit #3: Need a tip with building the plungercam? Want to collaborate on a project? Don't hesitate to drop me an email]

[Edit #4: See some of my other DIY projects (plungercam 1, iPhone SLR lens adapter, papercraft etc) here]

The original plungercam that I built earlier this year has been an absolute joy to use. However, the original design has a couple of problems.

1) The mounting mechanism to attach it to the camera uses a plastic body cap, which was never designed to hold much weight. As a result, the teeth on the cap have been slowly disintegrating under the weight (see inset, above). Mounting the lens has now become pretty unreliable.

2) Usage - there is a lot of fun to be had by forcing the user to tweak the focus by hand, meaning zero repeatability - no two plungercam shots will ever be the same. However, this means that it is unusable for time-lapse video applications, where it is important to keep the lens in the same place between shots.

I'll go through the construction of the dead simple Plungercam 2, which addresses the above two issues. It's worth pointing out at this stage that this is the first step in getting the plungercam to behave like a proper tilt-shift lens. Currently it only really handles tilt, so, strictly speaking, it's role is more like a very quirky selective focus mechanism than actual perspective correction.

Plungercam 2 keeps in the spirit of the original plungercam by using cheap plumbing equipment and affixing it to precision optics. This iteration eliminates the need for glue altogether, so all the optical components can be easily taken out and re-used elsewhere.

The main component is a rubberized pipe coupling, which I got for $7 at the always awesome Center hardware. The two adjustable steel bands will be used to hold the mount and lens securely in place. This particular one is two inches on the narrow end, and three on the wider end.

To fix the problem with the body cap mount teeth fraying, I decided to replace it with a T-mount T-mount adapter. I picked up the one I'm using for $3 from one of the closing Ritz camera stores.

I'm re using the $12 (from ebay) Zenza bronica medium format lens that was in plungercam 1. Since this was only held in place using a metal clip, it was easy to take it out and re-use it.

Total cost: ~$22 :)

The narrow end of the pipe connector is going to be connected to the camera; to maximise the usability of the lens, we want the narrow end to be as short as is practical. The general idea is to put the t-mount adapter into the narrow end, and to use the pipe clip to secure it into place.

Slide the pipe clip as far along as it can go along the connector, and score using a hobby knife around the edge of it that is going to be attaching to the camera. Remove the clip, and cut along the score line (again, a hobby knife will do the job here) to chop off the top of the connector. Keep the cut as perpendicular to the surface as possible.

My T-mount adapter was a little than two inches on its external diameter, and the connector itself is designed with a two inch fitting on its narrow end. With a bit of careful levering, the adapter can be wedged into the connector. Whilst it is a good fit, it's a good idea to put the pipe clamp back on and screw it tightly into place. Last thing you need is the adapter falling apart when it is on the camera :P

To finish the adapter, place the lens inside the wide end of the connector, and adjust to get the tilt desired. To fix it into place, simply tighten the screw clip. To reposition, loosen the screw clip, mess about with the lens position, and try again.

The design works because the mount is rubber, and the lens size is just a little less than the diameter of its mount. The lens sits comfortably in the mount, and the adjustable rubber gives it room to move when you want to tilt it. The metal clip (when tightened!) ensures that the lens can be held in place. The field tests that I've done so far have shown that the lens is indeed held pretty solidly in place.

The main drawback is that it's not as interactive as plungercam 1, and it takes much longer to set up a shot. On the other hand, you can definitely use it for time-lapse captures, which was a goal of mine.

It's definitely still a work in progress (I still need to add a rack to more precisely control lens shift as well as tilt), but results so far are not too bad :)

link to video