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DIY *one shot* wake-up + shutter release cable (e.g., Phase One IQ4 to Hasselblad V lens with leaf shutter)

onasj

Active member
DIY *true one shot* wake-up + shutter release cable (e.g., Phase One IQ4 to Hasselblad V lens with leaf shutter)

Ever since I started using medium format digital backs, I've wanted to be able to frame and focus an image in live view, then *while in live view* press a single shutter release button to trigger a mechanical shutter (not an electronic shutter, which causes rolling shutter artifacts with subject or camera movement) and have an image captured. This simple goal has been surprisingly difficult to reach for 54x40 mm digital backs without buying into a large and expensive pre-packaged camera + lens ecosystem, such as the Phase One XF or XT systems, or Hasselblad H systems, with proprietary lenses and bodies.

For those of us who enjoy building our own cameras from modular components, such as integrating ALPA bodies with Hasselblad lenses and Phase One backs, I’m not aware of an existing solution. Even using ALPA’s “one shot” sync cable with Phase One backs and Copal shutter lenses still requires manually shutting the diaphragm on the Copal shutter (which blacks out live view of course) before triggering the shutter, which really decreases the nimbleness and accuracy of framing and focusing in live view.

In a recent post (https://www.getdpi.com/forum/index.php?threads/diy-ALPA-compatible-modular-and-mountable-wake-up-cable.69216/) I described how to make a DIY wake-up button that plugs directly into the ALPA Y-shaped cable and mounts to a tech cam body. You can frame and focus in live view, then tap this mounted wake-up button to prepare the back for capturing and then trigger your mechanical shutter via release cable or shutter trigger button. But once again, this solution—while usable—requires an extra step between framing/focusing and capture, and I noticed that I was missing focus or framing of some shots as a result, especially when handholding the camera.

So I built a *true* one-shot wake-up + mechanical shutter release cable that plugs into an ALPA sync cable and wakes up the back just before triggering the mechanical shutter release—all in a single press. In total it cost about $50 of materials (beyond the sync cable, which most MFDB users already have) and took less than 2 hours to make from commercial components.

The key component is a very old Nikon dual shutter release cable, the AR-10. You can buy the AR-10 from B&H new for $30. This dual shutter release cable, despite its modest price, is cleverly designed and chocked full of useful components, including two high-quality microswitches that would cost me more than $30 to order. The AR-10 is a standard shutter release cable ending in a conical thread, but also has a second wire coming from the bottom of the release handle. That wire ends in a two-pin old-style Nikon motor drive connector. In its original use, pressing the AR-10’s shutter release button (plunger) would extend the shutter release pin, then near the end of the button press, would also close an electrical circuit with the Nikon motor drive, triggering the motor to advance the film.

I had the simple idea to repurpose that second wire to instead close the circuit on the wake-up cable of a MFDB, thereby waking up the back before the cable release would trigger the lens’s shutter. But the big problem with this idea is that the Nikon AR-10 triggers the motor drive AFTER the shutter is released, not before. Of course it would not work to wake up the digital back after the shutter is released. So we have to modify the AR-10 to change the timing of the electric circuit formation so it PRECEDES, rather than follows, the mechanical shutter release cable’s full pin extension.

When I disassembled the AR-10 (two simple Phillips screws), I was happy to see that the timing of the motor drive circuit closure was entirely “programmed” mechanically. A black plastic piece that moves down with the shutter release plunger closes the circuit once it reaches the bottom by alleviating spring-driven constant pressure on a normally-closed microswitch that otherwise keeps the switch open. In other words, pushing the plunger down almost to the bottom of the range pushes down a spring-loaded metal part that causes the motor drive circuit to close.
1.jpg

I realized that I could change the timing of the AR-10 so that the motor drive switch closes closer to the START of a shutter plunger press, rather than near the end, simply by installing a screw of about 1 cm long in the black plastic piece, so that depressing the plunger pushes down the spring-loaded metal part that closes the motor drive circuit much earlier than before. So I carefully drilled a tiny hole by hand into the black plastic piece, installed the small screw, and adjusted how far I screwed in the screw so that the plunger press closes the motor drive circuit about halfway down, which is well before the mechanical shutter is triggered on my Hasselblad V lens adapter or on my Copal shutter lenses.
2.jpg

Two more modifications are needed: the spring-loaded metal part that the screw now contacts is too slippery for the screw tip to reliably engage, so I wrapped that area of the part with heat shrink and glued it onto the part with CA glue for good measure (see the black heat shrink covering on the tip of the metal part). I confirmed that the action was 100% reliable at this point. Second, I put a blob of hot glue at the bottom of the AR-10 to secure the motor drive wire, which is not sufficiently secure in Nikon’s original design.
3.jpg

Then all that remained was to cut off the motor drive terminal plug, strip the two-conductor wires in the cable, and solder them to the jacket conductor and core conductor of some RG-174 coaxial cable, which ended with a female LEMO PCA.00 plug. The LEMO plug is the native partner of ALPA’s sync cable.Which conductor from the AR-10 you solder to which conductor on the LEMO plug doesn't matter since you are simply causing the circuit to close when the shutter plunger is pressed. I then used lots of black heat shrink to secure the soldered joined and tidy up the cable for a clean, professional look.
4a.jpg

The result is a modified AR-10 with a wire that connects to the ALPA sync cable, and a threaded shutter release cable that connects to your lens’s mechanical shutter. Amazingly enough, all of this works! Now a single press of the shutter release plunger wakes up the back just before closing the shutter, triggering the back to start capturing photons, then opening the lens’s mechanical shutter for the preset duration, then ending the capture. See the video here for a demo (play it with sound to hear all the mechanical events occur in sequence):
https://www.dropbox.com/s/8de0ly2xtwqwyz9/One-shot wake up cable IQ4 Hasselblad V.mov?dl=0

5.jpg

This DIY one-shot wake-up shutter release cable allows the Phase One IQ4 back, ALPA TC body, and Hasselblad V lenses with leaf shutters to all function beautifully together, with live-view framing and focus peaking and one-shot mechanical shutter release directly from live view, in a package that is about the same size as the Hasselblad 907x + CFV-II-50c + lens, but that outputs 150 MP, BSI, 54x40 mm sensor images instead of 50 MP, FSI, 44x33 images. Of course there’s no autofocus—a wonderful feature of the 907x set up when using XCD lenses. But for manual focus hand-held 54x40 sensor images with a large range of affordable, high-quality lenses in the Hasselblad V line, this setup is currently the most practical and nimble for me.

I imagine a similarly modified AR-10 cable can be used with other digital backs as an inexpensive one-shot solution to wake up the back and trigger a mechanical shutter in the proper sequence from a single button press.
 
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Phase V

Member
Little O.T. here, is the round plugin that goes straight in the back something you can buy from LEMO or any other
manufacturer?
 

onasj

Active member
Little O.T. here, is the round plugin that goes straight in the back something you can buy from LEMO or any other
manufacturer?
I’m not aware of a 12-pin connector source yet beyond Phase One or Alpa (or, I assume, other Phase One partners such as Cambo). The Phase One IQ4 wake-up cable is “only” around $100 and includes this connector.
 

buildbot

Active member
I’m not aware of a 12-pin connector source yet beyond Phase One or Alpa (or, I assume, other Phase One partners such as Cambo). The Phase One IQ4 wake-up cable is “only” around $100 and includes this connector.
I’ve spent a somewhat ridiculous amount of time trying to find a source of those 8 pin amd 12 pin connectors.

They are very old, and look medical almost - the push pull locking mechanism they have is used on a lot of plastic medical connectors it seems. It’s not a hirose or lemo connector either. It looks Kinda like an m6 mil spec connector, the type a connector pin outs/keying for those look almost right for the 8 pin, but every 8 pin plug seems to have a center pin. there’s also x keyed circular connectors for Ethernet that look like they could be hacked to maybe work, depending on the actual measurements.

interestingly there is one other place an identical connector jacket shows up - the old canon n3 remote release socket uses exactly the same locking plug connector, with only 3 pins.

whoevee makes these connectors is probably a Japanese company, since both canon and mamiya sourcedwhat looks like the same brand. It could still be custom to both of them anyway :/
 

onasj

Active member
Try asking Phase One or ALPA. ALPA is especially hobbyist friendly and they have been sending me encouraging emails after reading these posts about my odd homemade ALPA accessories :)
 

onasj

Active member
A small update: after a fair amount of designing, tinkering, drilling, and bolting, I secured the one-shot release cable as a side grip to the ALPA TC with two M3 bolts, a black anodized aluminum shoe mount with threaded M3 bolt holes, and an ALPA hot shoe adapter with thumbscrews. To be safe, I also installed a wrist strap to the TC frame, though the mounted one-shot release+grip combination seems to be sturdy enough to hold the entire weight of the IQ4+body+lens with no apparent creaking or flexing. Still, better to be safe—thus the wrist strap. The top hot shoe mount adds a leveling spirit bubble and a Profoto Connect for wirelessly triggering Profoto flashes.

Overall, it's a very practical and surprisingly nimble setup for shooting digital 54x40 mm with Hasselblad V lenses, their leaf shutters, and leaf shutter flash sync if needed. Just cock the shutter with the silver knob, frame and focus in live view, and press the release plunger—no other steps needed.

Screen Shot 2020-09-30 at 7.09.04 PM.jpg
 

Dan Burn-Forti

New member
This is such a great bit of inventing! I mainly shoot on an Alpa STC with an iq3 digital back, which works great. I also have an iq4 which is an incredible back and works perfectly with the PhaseOne cameras I also sometimes use, but having to press the button twice when using it on my Alpa is awful. I like to use it handheld and so that makes it impossible. Alpa haven't come up with any solution, but it seems that you have. Only problem is, it sounds so complicated to make if you're a clumsy oaf of a technophobe like me. Incredibly cheeky of me to ask, but I can but ask, but I don't suppose you'd consider making one for me?!
 

onasj

Active member
This is such a great bit of inventing! I mainly shoot on an Alpa STC with an iq3 digital back, which works great. I also have an iq4 which is an incredible back and works perfectly with the PhaseOne cameras I also sometimes use, but having to press the button twice when using it on my Alpa is awful. I like to use it handheld and so that makes it impossible. Alpa haven't come up with any solution, but it seems that you have. Only problem is, it sounds so complicated to make if you're a clumsy oaf of a technophobe like me. Incredibly cheeky of me to ask, but I can but ask, but I don't suppose you'd consider making one for me?!
Thanks, Dan. Realistically I don't have the spare time to make these for others, but it's really not too difficult (a fun project, even), and I'm happy to answer questions if you run into any problems.
 

AndyPtak

Member
Would something like this work on a Cambo Tech Cam with a P45+ back and Schneider lenses, and allow me to get rid of the Kapture Group wake up box? Thanks.
 

buildbot

Active member
Try asking Phase One or ALPA. ALPA is especially hobbyist friendly and they have been sending me encouraging emails after reading these posts about my odd homemade ALPA accessories :)
They actually told me it Phase One wanted to keep it a secret actually BTW :cautious:
 
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