21 February 2020

How to build your own Goodman ZONE camera, part 2

How to print and assemble your own Goodman ZONE camera.

By In Make, Photography 17 min read

The Goodman ZONE is a medium-format 3D-printed film camera designed by Dora Goodman as part of her range of open-source camera models, using the existing Mamiya Press lens series for glass and the Mamiya RB67 backs to hold film. This is part 2 of a series on building your own Goodman ZONE.

Download files

We start by downloading the design files for this project. Dora has made all files available as an open-source project on the Goodman Labs site, but does require you to register as a member to download them. Register an account and log in, then visit the Downloads page which leads to several Google Drive links.

The ONE, ZONE and AXIS cameras are considered related designs and are bundled within the GOODMAN_ONE folder. This folder also contains the READ_ME change-log that is updated whenever Dora makes changes to these files. As of this writing, the last update on the change-log was on January 8, 2020. Once you enter the GOODMAN_ZONE folder you’ll find everything you need:

This folder is very complete, but gives you a lot of things to click on straight out of the gate. It’s tempting to just head straight for the STL folder, download everything there and start printing – it’s what I did. But you’d be printing an outdated version of the ZONE, because there’s a newer model in the ZONE_V2.0 folder that Dora uploaded on October 27, 2019. This V2.0 is also the same model that her pre-printed kits and the corresponding videos and documentation are based on. I also use V2.0 for this guide.

From the ZONE_V2.0 folder you want to download the ZONE_body.stl and lens_holder.stl at the bare minimum. These are the main ZONE camera body, and the lens holder ring that will keep your lens in place.

To buy (camera parts)

The standard Goodman ZONE body is designed to fit a Mamiya Press lens and Mamiya RB67 film back. These are 2 different camera systems from Mamiya which can be confusing, so to be clear, the unmodified ZONE body WILL NOT fit Mamiya Press film backs nor Mamiya RB67 lenses. Make sure you buy the right ones. Both Press lenses and RB67 backs have not been in production for decades so remain easiest to find online, on sites like eBay, or photography forums and marketplaces.

The cheapest Press lenses are the 100mm f/3.5 and 90mm f/3.5, which were sold as kit lenses with the Press camera. Shooting with these on a Zone is not too dissimilar from shooting with a ‘normal’ 50mm lens on a 35mm camera.

The RB67 film back is available in Pro, Pro-S and Pro-SD variants. The standard ZONE only fits the Pro and Pro-S variants. The more modern Pro-SD has a different mount and requires a modified ZONE body. If you do accidentally find yourself with a Pro-SD body, there is a modified ZONE back in the ZONE_MODS folder that takes SD backs.

AmountPart
1Mamiya Press lens
1Mamiya RB67 Pro or Pro-S film back

Dora provides 2 types of viewfinder: a sports viewfinder or a printable version based on a cheap macro lens from eBay. Alternatively, you can entirely forego the printed viewfinders and use either the original external viewfinder that belongs to certain Mamiya lenses, or buy an aftermarket external viewfinder accessory. For example, while rummaging through my old camera gear I found an external viewfinder from a Lomography Diana kit that corresponded decently to the 100mm lens field of view. Works fine for this purpose.

Optionally – but I would highly recommend it – you can buy a shutter release cable. The shutter-release button is on the front of the Press lens, but fitting this cable with a printable accessory lets you reroute the shutter release to the side of the camera body for ease-of-use. A short 15cm cable is perfect for this use, though they may be harder to find. I had to buy a secondhand model from eBay as all new cables I could find online were much longer.

AmountPart
1External viewfinder
1Shutter release cable

To buy (hardware)

Dora has a list of parts – socket cap head screws, set screws, and nuts – required to mount the lens, film back, and any other accessories you want to fit, in the ZONE_HARDWARE document in the GOODMAN_ZONE folder. I found that hardware stores in my area did not carry the smaller sizes of socket cap screws. Instead, I ordered my parts from a Dutch webshop, linked below for reference. You should be able to find similar suppliers in your own country, though the ‘Allen’ name is specifically American and may make it harder to find the right parts in your language. It’s also commonly known as ‘inbus’ or ‘hex’. I added the relevant DIN standards to help you find the parts no matter what language you speak.

AmountPartDIN
6M3 x 10 mm Allen socket cap head screw 912
7M3 x 12 mm Allen socket cap head screw 912
8M4 x 20 mm Allen socket cap head screw912
2M3 x 6 mm Allen socket cone point set screw 913
7M3 x 12 mm Allen socket flat point set screw 914
13M3 nut934
8M4 nut 934

Note: Instead of loose screws it’s probably cheaper to buy a boxed assortment of M3 and M4 Allen screws from sites like Amazon or your local equivalent. That way you’ll also have the option to pick screws specifically for each accessory you mount. Just remember that you still need to buy the set screws, they don’t come in the boxes.

The hardware that Goodman ships with her kits are colored black to match the black body. I decided to mimic the color scheme of my Mamiya Press lens instead, which is black with silver details, and bought A2 grade stainless steel parts.

Next you’ll need some 1/4″ to 3/8″ thread convert screws. These small metal adapters are normally used to convert professional 3/8″ thread tripod mounts to the more widely used consumer 1/4″ thread. On the ZONE this adapter is used to reinforce the 3D-printed plastic tripod mount and give it metal threads.

AmountPartDIN
21/4” to 3/8” thread convert screw

You will also need three sizes of Allen key. The 3mm key is needed for the M4 screws, the 2.5mm key for the M3 screws and the 1.5mm key for the M3 set screws. You can buy these from the same web-shops, but if you often work on hobby projects like these you probably already have them in your toolbox.

The last thing you need is some light seal adhesive. This is a sheet of squishy material, like felt or rubber, with an adhesive backing. You can buy either official light seal adhesive meant for camera repair, or buy something similar from hardware stores. I personally opted for a sheet of anti-slip DIY rubber that was noted in some amateur camera repair forums as an affordable alternative to official light seal adhesive.

AmountPartDIN
1Light seal adhesive

To print

The ZONE was designed to be a single print that requires no support, with all parts designed using gently angled overhangs. It’s an elegant design that is optimized for printability, making it easy for even a beginner at 3D-printing to successfully print this camera. The trade-off is that both the lens and back have to be attached using set-screws that will hold them using friction. There are no complicated mechanisms to lock these in on the ZONE.

Many people print their ZONE in standard PLA. This is fine for most cases, but PLA can be susceptible to melting in hot environments like a locked car during a long summer’s day. Dora’s pre-printed kits are printed in Colorfabb nGen, a co-polyester designed to be a better all-round material than PLA, with a better thermal resistance. A lot of people like printing the ZONE in PETG, also a co-polyester that shares nGen’s improved specs, but be wary that many PETG filaments are not fully opaque and will result in a slightly transparent body that will always leak light.

As you might imagine, light leaks are an issue. Your ZONE body has to be fully opaque to avoid light leaks on your film and get the maximum image quality out of the camera. Even glossy filaments can cause trouble: reflective surfaces on the inside of the camera can also wreak havoc on the quality of your shots. You can print in either a matte, fully opaque filament or compensate by flocking, painting, or taping the inside of the body. Honestly though – just print in opaque black for your first body. Start experimenting with crazy filament colors once you’ve got a working model under your belt.

We printed our ZONE body in Ultimaker’s Tough PLA Black. It’s still PLA, so an easy filament to work with, but contains additives that raise the temperature resistance enough that we don’t have to worry about the summer car scenario. Because the ZONE has been designed for easy printability you can print it without supports, with the round lens-side down on the build plate.

Dora recommends sanding the print prior to assembly, and even ships a sanding sponge in her kit. I’m not a fan of the sanded look and prefer seeing the layer lines, but feel free to do whatever looks best to you.

The trim on her 3D-printed camera designs is not nearly as intricate as her work on vintage cameras, but she does provide cut-out files so you can make your own trim out of leather, wood veneer, or any other thin material. You can find them in .AI (Adobe Illustrator) format in the ZONE_V2.0\CUTOUT SAMPLE FOR VENEER\ folder as zone_final_m.ai.

To assemble

Dora has an assembly video for the ZONE on the Goodman Labs YouTube channel. My guide goes into a bit more detail, but it’s worth watching the video before continuing your assembly!

Take the body and hold it like you will use the camera once finished – with the round hole pointed away from you, and the ‘Z1’ marking facing upwards. You’ll find that the body is distinctive on all sides. The top is marked ‘Z1’, the bottom has a tripod mount and is marked ‘OPEN-SOURCE GOOD ZONE’, the right is marked ‘OS’ and the left has just a tripod mount. The front has a circular hole for the lens, while the rear has a rectangular hole for the film. This is how we’ll reference each side from now on.

Let’s get started!

Tripod mount

AmountPart
21/4” to 3/8” thread convert screw

We’ll begin by screwing in the tripod mounts. There are plastic 3/8″ threads on both the bottom and the left side which we will reinforce with metal adapters that fit standard 1/4″ tripod screws. Insert the convert screw into the bottom mount and gently screw it into the body using your fingers. You can use a coin – a 10 euro cent fits perfectly – to lock it in.

Don’t use too much force when using the coin, the adapters were not meant to be self-tapping so if the threads get stuck in the plastic you can shear off the adapter (been there, done that). Then, repeat the process with the mount on the left side.

Lens mount

AmountPart
4M4 x 20 mm Allen socket cap head screw
4M4 nut

The lens will be mounted using 4 M4 screws on the front of the camera. Each screw is held by an M4 captive nut that goes into the corresponding corner of the body.

Hold a single nut in place on the inside and start screwing the M4 in from the front using your 3mm Allen wrench. All screws will have to tap their own thread through the plastic the first time you insert it into a hole, so it’ll be a bit rough at first. Once the screw finds the nut, keep on screwing it in. You’ll find that the nut is pulled deeper into the body by doing so.

Make sure that you keep screwing until the nut fully bottoms out in the body. You’ll feel a difference between the screw still rotating easily, to it suddenly feeling very tight. Don’t force the screw beyond that point – you can crush the plastic between the screw and the nut. You know you’re definitely deep enough when the nut is flush with the inside of the body. Once the nut has bottomed out it’ll be stuck and will remain locked inside the body even when you remove the screw. Repeat this process for the 3 other M4 nuts and screws.

Now that the captive nuts for the lens mount are locked in place we can remove the screws again. Unscrew them, blow off the plastic shavings that are probably caught in the threads, and put them aside – we’ll use them to mount the lens later.

Grip attachment points

AmountPart
4M4 x 20 mm Allen socket cap head screw
4M4 nut

We’ll continue by adding the attachment points for a grip on the left and right sides of the body. The grips will use the rear-most attachment points there and will be held in place on each side by 2 captive M4 nuts.

Follow the same procedure as with the lens mount: hold an M4 nut in place on the inside, then screw in an M4x20 screw with an Allen wrench from the outside until the nut bottoms out. The nut will be locked into the body and stay in place even when you remove the screw.

Repeat the process for the 3 other M4 nuts and screws.

Even though we’re not mounting a grip yet, all of these attachment points need to be filled with screws or they will let light into the body – not a good thing. So unlike the lens mount screws, you can leave these in place.

Front attachment points

AmountPart
6M3 x 10 mm Allen socket cap head screw
7M3 nut
1M3 x 12 mm Allen socket flat point set screw
1Superglue or Sugru

There are 3 front attachment points for accessories on the top, left, and right side of the body. There’s also a single set-screw on the bottom that will help keep your lens in place. All of these are mounted using captive M3 nuts, but unlike the M4 nuts these will not get locked into the body once you’ve inserted your screws. You can use superglue or Sugru to lock these nuts in. This is optional, but if you don’t lock in the front M3 nuts and you remove a screw while the camera is fully assembled, the nut may escape and bounce around inside the camera and damage your lens.

Each attachment point uses 2 screws to hold an accessory in place. That’s why there are 2 slots cut inside the top, left and right side of the body. Insert M3 nuts into all 6 slots and screw M3x10 screws into the corresponding holes.

Note: As with the grip attachment points, even though we’re not adding accessories yet, we need to keep all of these holes filled with screws or they will let light into the body. When we do add accessories, we will replace the M3x10 screws with longer M3x12 screws.

The last nut goes into the bottom, where just a single slot has been cut for a captive nut. This nut will not hold a M3x10 screw, but instead take a set-screw.

Insert the nut on the inside and hold it in place. Start screwing in the flat-tipped M3x12 set-screw from the bottom using the 1.5mm Allen wrench. Stop when the tip reaches the edge of the lens mount. If it protrudes deeper into the body it will block the lens from mounting properly.

Note: If you’re using a heavy Mamiya Press tele lens, or just want a more secure mount for your lens, you can add 2 additional set-screws to hold it in place. You’ll have to forgo using the left and right front attachment points though, as the set-screws will take the place of the top M3 screw on either side.

Rear attachment point

AmountPart
2M3 x 10 mm Allen socket cap head screw
2M3 nut

There is just one attachment point left to handle, on the top of the body near the back. Insert M3 nuts in the slots cut into the top middle of the back. Once the nuts are in, screw in the M3x10 screws from the top.

You’ll notice that the standard M3x10 screws are long enough that they can interfere with the film back. If you screw them all the way in against the body, they’ll protrude beyond the bottom edge. This doesn’t happen if you use them to mount an accessory, but for now it’s best to unscrew them slightly so they no longer block the back from being mounted later.

Film back mount

AmountPart
4M3 x 12 mm Allen socket flat point set screw
4M3 nut

We’re in the home stretch now! Your ZONE body only needs the last nuts and set screws that will keep your film back attached to the body. Insert the 4 M3 nuts into the slots cut into the 4 corners of the body at the top left, top right, bottom left and bottom right.

Insert a M3x12 flat point set screw into each outside hole and screw them into the captive nuts using the allen key. Make sure you use the FLAT set screws here. This method, screwing and unscrewing the set screws with an allen key, will also be the way you mount and dismount the film back to the ZONE body. You should not forget the key if you go out shooting and want to swap backs.

With all the screws now in place you’re ready to go the next phase.

Light seal

AmountPart
1Light seal adhesive

The interface between the ZONE body and the Mamiya RB67 film back has to be covered using light seal material. This is a light-blocking material with an adhesive backing that you can cut and apply to the back of the ZONE. This will make sure the interface between the ZONE body and the film back is light-tight.

Goodman Labs has a great video tutorial explaining how to cut and apply the light seal adhesive, just follow it and you’ll be golden.

Lens and Lens Ring

AmountPart
2M3 x 6 mm Allen socket cone point set screw

We’re almost at the end now. The lens ring keeps your lens in place and takes 2 M3x6 cone point set-screws. On the edges of the lens ring you will 2 holes for the set screws. Screw them in with the Allen key, but make sure they don’t protrude past the inner edge of the ring.

Slip the lens into the round hole on the front of the ZONE body. Make sure that you rotate the focusing scale to the top, aligning the red triangle with the center of the top plate. Slip the lens ring over the lens and align it with your ZONE body. Screw in the set-screws you inserted into the ring with the Allen key slightly, until you feel that it doesn’t slip off the lens easily anymore. Don’t overdo this – you don’t want to screw directly into your Press lens. Now grab the 4 M4x20 screws you used in the lens mount phase earlier to mount the ring to the body. Screw them in so the lens and the ring are mounted securely.

The last thing you should do – remember that lone set-screw on the bottom of the front attachment points? Screw that in gently – same as the other set-screws.

Film Back

Almost there! On the other side of the camera, press the RB67 film back firmly against the light seal layer you’ve applied to the back. It should slot neatly in between the top and bottom mounts of the body. Grab your allen key again and screw the flat set-screws carefully against the back. Take a LOT of care here, as it’s possible to damage the film back by screwing the set-screws too far. Applying too much pressure this way can easily dent the back. The goal is to make the screws grip the back enough to keep it securely in place while shooting. And that’s it.

Congratulations! You’ve finished your first Goodman ZONE build!

What do you think?