A Trip To The Armouries

Yesterday a friend and I went to the Royal Armouries in Leeds, he had just got a canon 400D and wanted some tips on using the shutter priority and aperture priority modes. I said as a general rule of thumb, to avoid any motion blur from shooting handheld always use a shutter speed of 1/focal length ie at 50mm don't go slower than 1/50, at 300mm don't go slower than 1/300. A quicker shutter speed is needed at longer focal lengths (more zoomed in) because the shake of your hand is amplified.
This was put to the test when we went inside the museum, where even with the aperture wide open (low f numbers, 2.8 or 4) we were still getting shutter speeds too slow to hand hold, flash would have been helpful or better still a tripod but I think we would probably have been shot at by the guards if we even attempted to break out the tripod, so we just cranked up the iso settings.
The test was a bit extreme but it helped my friend get to grips with the relationship between shutter speed and aperture, we also had a go at panning shots (of people jousting none the less) but thats another story. Anyway for those still reading this shot was done at 1/400 at f8 at 38mm, I realise this wasn't exactly practicing what I preached but I was at iso 800, I would have rather been at iso 100 for 1/50, but I was lying down and the suspicious looks of the guards watching 2 seemingly pro photographers was making me a little uneasy.