The Mamiya C330 TLR is currently gaining popularity. Deservedly so, it is a widely underrated medium format camera. Judging by online discussions of the C330, one frequent problem is a sticking shutter. So if you are new to the C330 and your shutter does not fire, here are three non-problems to identify before you send the camera or lens for a repair & service:
1. The shutter lock.
Yes, it seems obvious: don’t put on the shutter lock if you want to take a picture; it even tells you as much in the manual. The problem is, that the shutter lock is almost too small to notice -in the earlier models in particular- and easy to engage by accident, e.g. by moving your camera in and out of your camera bag.

So check your shutter lock, if the lock button is under the ‘L’, just push it forward to unlock.

2. The lens lock
The C330 is an exchangeable lens camera, but is owned by many who don’t have lenses to change. If you are new to this system, you may look at the lens change knob on the left and attribute the ‘lock’ and ‘unlock’ positions to the shutter rather than the lens. This matters, because the lens change mechanism affects the shutter: in the ‘unlock’ position, the light path inside the camera is blocked to protect the film during the lens change. In this position, the shutter is obviously blocked to avoid blank frames: it would be easy to forget the lens-knob setting since the viewing lens is not obstructed.

In the ‘lock’ position, the lens can’t be removed and the shutter can be activated – i.e. the shutter can now be unlocked, it is the lens that is locked.

3. The flash-sync selector
Out of the three, this is the one mistake that can trip up more experienced users. The flash sync setting on the lens mounted shutter can be in two positions: either X for modern electronic flashes or M for old style flash bulbs: it often sticks when set to M but may work fine when set to X.

Old style flash bulbs (the type that James Steward uses in Rear Window) needed a split second warm up time for which the M setting allows by adding a 20ms delay prior to triggering the shutter. Of course, hardly anyone has used these bulbs during the last half century, so like old self timers, this flash bulb setting is likely to malfunction. Sometimes the delay will be a bit longer than it should be, on other occasions the shutter won’t fire at all. As with obsolete self timers, the easiest solution will be to just not use this setting.

Then of course the shutter may stick with all of the above ruled out, in which case the lens does need a service.