Over the last week or so I've been photography a damaged cast iron statue of a hindu god(ess) - much of it in close detail.
Having done some in 8x10, I started yesterday with the arca swiss, doing more in 4x5.
I set up, focussed in nice and close, head under the darkcloth, loupe to the GG and got nice sharp focus on on of the eyes. Then stuck the quick-disc in front of the stature to work out the bellows extension factor - went back under to measure the disc diameter and found the focus had shifted. Reset it, came out again to check the light and set the exposure - back under for a quick check and darn... focus has shifted again. Re-set it, took the photograph, double checked the focus and it was okay - phew.
Moved the statue a bit, re-adjusted the camera. composed, focussed, check the quick-disc, re-chack the focus - damn - it's shifted again. Re-set focus, check the light - shifted again - just couldn't figure out what was happening.
After re-focussing once more, came out again to set the shutter and aperture and as I do so, see a little hand moving under the dark-cloth drapped camera.
The tripod was pretty low and my 17 month old's head was just about at tripod head height. He had been stood almost under the camera (whichI knew), but had been faithfully watching what my hands were doing - so each time I came out from under the darkcloth, his little hand would go up to the arca focus knob and twist it back and forth just like daddy was doing.......