DIY Electronic Shutter Release for the Manual Minolta SLR
use vintage 80's manual focus Minolta X-370 cameras for stereo
photography. This entails using two cameras side by side and tripping
the shutters simultaneously. The Minolta camera
shutters can be tripped in the usual way with the
finger switch on the top, or by a mechanical cable release in the
cable release socket. Up to now, I tripped the camera
with a homemade dual cable release. But moving or changing the
position of the cables introduced error in the synchronization, so I
tripping the shutters in a better way.
The X-series manual Minolta SLRs I'm familiar with utilize an
electro-magnetic shutter controlled with an electronic circuit. While
the cable release socket on the side of the
body functions with a standard mechanical cable, I found that the cable
release socket can also function electrically.
cable release socket on the camera body has inside an electrically
"hot" tab that, when
grounded, trips the shutter. So the shutter trip can
happen in two different
1) A standard mechanical plunger type cable release can be
installed into the socket, and when you push the plunger, the cabke tip
goes in, pushes the electrically "hot" tab to ground, and consequently
trips the shutter.
2) An isolated electrical wire can be installed into the cable
socket with a conductive tip, and when you simply short the other end
of the wire to the camera ground, the shutter trips.
had a remote shutter release system called the IR-1 which used a
remotely held infrared source transmitter unit to trigger a receiver
base unit placed near the camera body. The receiver base unit was
attached to the camera cable release socket with an electrical
cable. I have not seen this system first hand, but I believe
IR-1 electrical cable shorted the internal tab to ground.
probing the tab inside my X-370 and shorting it to ground, I found that
the electrical method works. I decided to make a pair of
electrical contact mechanisms which plug into the cable release sockets.
concept is to position an insulated wire through a cable release
ferrule (or jack) so that it touches the electrically "hot" tab inside
the socket. The insulated wire can be wired through a
open (NO) momentary switch to the camera electrical ground. The tab
now be easily grounded through the external switch to trip the
considering a "homemade" cable ferrule with an
electrical wire tip, it is important that the wire tip of the cable go
deep enough into the socket to contact the tab, but not so far that it
pushes the tab down to the electrical ground behind
sure Minolta had a specified length for the tip of the IR-1
"jack", but since I don't know it, I'll have to figure it out.
Rather than go through
trial and error with different length tips, I devised a mechanism in
order to adjust the depth of the wire tip as it comes out of the cable
release housing. It is comprised of a nylon screw with an integral
insulated wire which can be threaded in and out of the cable release
jack. A standard cable release jack is used, but it is
to incorporate a threaded bushing so the nylon screw can thread in and
I harvested a couple of threaded
ferrules (jacks) from some regular ol' cable releases. The two I
harvested were glued and the mechanical cables and tubes came off with
tug. The old glue was then cleaned out of the I.D. of the ferrule
threaded bushing (a
4-40 threaded hex stand-off) is
affixed to the sleeve of a "harvested" standard cable release
jack. One half of the I.D. of the bushing is drilled out in
to slip-fit over the cable release sleeve. The photo on the right
shows the standoff with its bored out I.D. facing up.
The bushing is bonded to
the ferrule sleeve.
center of a 4-40 threaded nylon screw is drilled out to allow
a solid core 22 AWG wire to pass through. I
had access to an ancient mini lathe to drill out the screw, so I got
fancy and drilled two different sizes to make a shoulder for the
insulation to bear against. It would be fine to have the larger bore
all the way through and just epoxy the insulated wire into the screw.
The dashed lines shown illustrate the bore.
22 AWG solid wire is
employed since it's stiff, and the O.D.
of the insulation fits nicely in the bore of the cable release jack.
The end of the wire which will contact the tab inside the camera is
stripped to expose about 1 mm. The output end of the wire
passes through the screw and can be terminated to your switch.
The wire is bonded to the screw.
nylon screw/wire assembly can now be threaded into the bushing and
screwed in or out
to adjust the depth of the wire relative to cable release jack.
you can see they have quite a range of adjustability for wire depth. It
works fine, but after I was finished with this pair, I
to scale down the gizmo and use a shorter bushing, and a shorter nylon
On the bottom is a new
smaller assembly; it's concept is the same, but it's shorter, and
doesn't stick out as far. It'll be less prone to being snagged during
use in the field.
Here is the device
installed on my Minolta X-370. I have not yet wired the
output wire lead to a switch.
To install and adjust the wire tip depth:
Before installing, back off the nylon screw/wire assembly so
the tip is flush with the end of the "jack". Install the cable release
jack firmly into the cable release socket of the camera. Advance the
film lever and turn the camera on. Turn the nylon screw/wire assembly
in until the shutter trips. This finds the limit of how deep the wire
mechanically goes to push the tab to the internal ground. Back
off the screw/wire assembly 1.5 turns. Backing off the wire
keeps the tab from being too close to the internal ground, but not so
far that the wire tip loses contact with the tab. You may have
to experiment with how much to back off the nylon screw, especially
with different "X" Minolta cameras. Once the wire tip is adjusted, it
should not be necessary to adjust it again.
To test the cable
Make sure the camera is on. Advance the film lever.
Using a switch or simply a jumper wire, short the cable release wire to
the camera ground. The top metal cover as well as the bottom are case
ground. The shutter should trip.
If testing is successful, you can now wire up any ol' type of
switch you'd like.
I have not yet tried how a latching switch works on the bulb
setting. I'll check it out and update...
- The "harvested" threaded cable release ferrules
- A 0.250" width
hex standoff(bushing) x
0.375" length, with a 4-40 internal thread, or use whatever
standoff/bushing you can scrounge.
- A 4-40 thread x
0.5" length panhead nylon screw
- A length of 22
AWG solid core wire
I came across this website within days of coming up with my electronic
cable release. The author came up with the same concept for
tripping the shutter. The author also came up with a very
remote release by using an RF doorbell kit.
This is a Yahoo Groups message board for fans of manual focus Minolta
equipment. Several members were extremely helpful with my