If you have been in camera scanning even for a week, you’ve probably seen this copy stand arm with a screw dozens of times — cheap stand or expensive one, it ends in a twist knob that threads into your camera’s tripod socket. And most of you know the drill: leveling the camera so the lens axis is perpendicular to the stand’s base takes a lot of time, checked with a couple bubble levels or, better, the mirror trick. And you know the moment right before you’re done — one last twist to correct the last fraction of a degree in camera orientation — and the screw lets go instead of holding and your camera get loose and twisting again. With a heavy body and lens, fixing that rotation (roll) still leaves the tilt (pitch/yaw) to sort out separately, so you basically hate the process and push back the moment you have to set up your rig.
The issue is - the standard 1/4"-20 screw holds the camera by pure friction between camera base and mount’s cork or rubber strips. So you nudge, it slips, you re-level, it slips again — and given how uncomfortable the grip itself to hold - you’re also worried about stripping the tripod socket underneath. You’d badly like to have Arca-Swiss instead of the primitive screw, but even established rig manufacturers mostly pass on Arca-Swiss clamps.
Of course, the correct fix is a dedicated camera cage or L-bracket with an Arca-Swiss plate. The corrsponding clamp with matching Arca mount can be attached to the stand arm with as much brute force as you can manage. You do this once, carefully, and it holds for good; the camera can’t rotate independent of the rig and is less susceptible to vibrations. But that only works if a cage exists for your camera body, and plenty don’t: older digital bodies, oddball mirrorless, anything not popular enough with vloggers ;-). A standard rubber-lined Arca-Swiss camera plate doesn’t help much either — it still relies on just a screw with D-ring.
Caption: Leofoto NP-60 and Breakthrough Photography old style plate.
It only dawned on me recently that there’s a pretty simple cure for this: a mount plate with so-called “anti-twist lip”. If you’ve known about these for ages, my apologies for the wasted time — nothing below will break new ground for you.
The workaround I am talking about is this: an Arca-Swiss compatible plate with an anti-twist lip — a raised edge near the screw hole, fixed or retractable, that presses against the edge of the camera body.
The screw slot has about an inch of travel before it fully seats — start the screw, but before it’s tight, slide the plate so the lip jams against the front of the camera, then finish tightening. The lip takes the rotational load instead of pure friction force, so the camera can’t spin loose as usual.
Caption: Leofoto NP-60 and Breakthrough Photography old style plate on camera. Note: the Leofoto plate lets you adjust the lip height, while the old BP lets you adjust the lip after the plate is screwed in.
Of course, you still need to fine-tune the clamp on the rig side — which is fine, since that connection can take much more abuse: no delicate parts there, and no danger to the camera’s tripod socket.
Best solution overall is a 2- or 3-axis Arca-Swiss geared head for precise leveling, though it’s not cheap and adds weight of its own. Skip leveling platforms or inexpensive small ball heads — in my experience they shift during final tightening. On the inexpensive side, your best bet may be a leveling film holder, if it’s equipped with adjustable legs (like VALOI 360).
Anti-twist lip plates run roughly $15–95 depending on build quality and dovetail compatibility — search “anti-twist” or “anti-rotation lip.” Works on any body that has an edge for the lip to press against — cage or no cage.
Hope this helps.
Update: when I mentioned leveling platforms I meant those “leveling bases” or “leveling heads” like pictured below in my response to @Harry . I think they intended to work in vertical orientation, in camera scanning scenario - it’s horizontal orientation -camera and lens create strong tilting effort which those devices are not meant to handle IMHO
