Look at the streaks of white where the snow was falling yesterday. It's a view of Grasmoor from Fleetwith Pike. It occurred to me that if I knew the exposure time I'd stand a chance of working out the speed of the snow by estimating the length of the tracks. I found an online camera manual which said the shutter time was between 3EV and -3EV. Detective work says that EV stands for Exposure Value. EV is calculated as Log(base 2) of F-number squared divided by exposure time. More on some of this later, but the F-number on the front of the camera is 2.8. The problem is that the camera automatically sets the value. It can't be 0EV because that calculates out at an 8 second exposure time. If it has set itself to 3EV then the exposure time is 0.98 seconds. But I suspect it is less than that because for example a photograph of the second hand on a watch would be blurred. I need to do some thinking about this.
