There are generally a few curious souls that come over and ask what I'm taking pictures of and whether I work for a magazine or something. I simply tell them no, I'm just an amateur. There have been a few more memorable occasions, though...
Quite recently, during a frustrating attempt (hot day, lots of people about) to get some waterfall shots the icing on the cake was when one knuckle-dragger with a cheap compact digi-gizmo came up while I changing lenses and prodded at the F80 body on the 'pod saying, "That digital?" I said, "No" and he turned in disgust, stomped off and, in doing so, kicked the 'pod leg and nearly sent it (and the Nikon) down a fifty-foot drop! I, er... remonstrated with him at some length...!
Last year while I was taking pictures in Wigan station (for the APUG anniversary, as it happens!) I got quite a lot of attention. Apart from a drunken Scot (is it the same one at every station (The Flying Scotsman?!) or do Network Rail have a large staff of them?) and several people wanting to know from where their train was leaving (man in casual clothes with camera, tripod and several lenses = station staff?! :rolleyes: I must have an aura...!) there was one slightly odd encounter.
I'd set up the 'pod with the camera looking down a tunnel that ran under the tracks. The idea was to have everything in the shot pin sharp with one or more blurred figures passing through (one of my rare "artistic" moments!). To keep the action of taking a shot inconspicuous I ran a cable release down the 'pod leg and busied myself cleaning my gear as if I was still setting up, tripping the release as people passed by.
During one of the gaps in the flow of people, a (let's be polite) 'large' woman walking slowly down an adjoining tunnel behind me stopped and called something out, a bit aggressively. I didn't quite catch it but put on my best polite enquiring face and got her to repeat it.
"What are you filming?"
'Filming?!' Not wanting to split hairs I pointed in the same direction as the camera and said I was taking a picture of the tunnel.
"Have you got permission?"
Actually, as it was technically private property, I'd had a word with the station master before I started. With it being a Sunday morning and not exactly rush hour he didn't give a damn as long as I didn't play on the tracks! I told her that yes, I did have permission, and she stomped off with a disappointed air.
It wasn't until later that I wondered about it. She definitely wasn't station staff, she was behind the camera and I wasn't taking a picture of her, I wasn't blocking the tunnel or delaying anybody (indeed, I think several people only caught their trains because of my directions! I should have got a commission!

)... So what was her problem?! I suppose some people aren't happy unless they're disapproving of (and, if possible, interfering with) other people's enjoyment...
The final occasion was when I was taking some shots of a fountain near where I work at the Pier Head in Liverpool. I'd been shooting from a 'pod (as usual!) for a while when I decided to pop-up the flash and use some weak fill to try and add a bit of sparkle to the water. A few minutes later I looked round to see a security guard shoulder-surfing me.
"What are you doing?"
Never afraid of stating the obvious, I told him I was taking photographs. He mulled this over for a while...
"What of?"
We were standing in a courtyard with nothing around but very boring office buildings and one fairly spectacular twenty-five foot fountain at which the camera was conspicuously aimed... I told him I was taking pictures of the fountain for my photography evening class. Another pause...
"Can you prove who you are?"
By this time I was getting more than a bit cheesed-off with this. I was in a public place taking pictures of a fountain during my lunch hour and, apart from anything else, didn't need the interruption. I considered telling him to go forth and multiply but instead smiled politely and dug out my student library card. While he scrutinised it (brow furrowed, running his finger under the words and moving his lips) I asked him if there was a problem.
He then pointed out that the building *behind* the fountain belonged to the Ministry of Defence...
Ah. Oh.
He gave the card back and I carried on taking shots for another 15 minutes or so... ...but I'm quite glad I kept that encounter on an amicable footing!