In reply to Godwin:
> I wondered about that. I have never understood fall factors, but I do know I found that top out hard, and felt fall offable. And wondered if as the second went past the belayer and fell backward, there would be maybe 3 or 4 feet of rope out, so they may fall 6 or 8 feet below the belay device, and thought this maybe a bad thing to happen.
In theory, the fall factor is simply the distance fallen divided by the length of rope out. So for single pitch falls the FF cannot normally be greater than 1, since falling 10m with 10m of rope out would land you on the ground. For multi-pitch the FF cannot normally be greater than 2, which would mean having no gear in, falling straight past the belayer and a similar distance below.
In practice the FF has a big effect on the abruptness of the fall, as it's very difficult to give any kind of soft catch with a FF2 fall.
Taking the OP's photo as an example, let's assume rope stretches around 10% in a fall (which is probably an overestimate except in severe falls but good enough for the example). Falling off the top mantle move (at around 10m height), with gear 1m below you, will give a 2m fall on 10m of rope, but then the rope will stretch by up to a metre, extending the fall to 3m but giving plenty of cusioning in the process. Falling from the same place with only 1m of rope out will still give a 2m fall but the rope will stretch only 10cm or so, which is hardly anything, and it most likely will feel like a very hard fall. All this would be compounded by there being little to no help a hanging belayer could give in giving a dynamic belay, compared to a belayer on the ground who could easily allow himself to be pulled up another metre or so, thereby elongating but cushioning the fall yet further.