Hi!
I'm sorry but I disagree with the "hair" method because it's completely unreliable. Other parameters, like humidity or nutrient issues, can have effect of the pistil colour. For example, if I had followed this rule for one my latest grow, I would have cut the plant 3 weeks earlier than by looking at the trichomes, just because at this time the plant had running low in phosphorus and new flowers grow slower, resulting in more amber pistils.
The trichome method is the only reliable way to identify when harvest, because that's where the cannabinoids are stored and you can literally see them. It's up to you to choose if you like more you weed with high/cerebrals effects (more cloudy trichomes) or stone/body effects (amber trichomes).
But it's not easy to see the trichomes with the poor quality of a compressed camera-phone image, you may have a better view with your bare eyes through your magnifier, or may need a better one (grow shops generally cheap plastic ones who does the job). Real camera with good macro lens can also work (this is how I watch the flowers and make photos for my diaries).
Colours of the leaves are also a good indications of the maturity of the plant. Purple colouration and senescence are generally signs of the maturity of the plant (but may not happened at all).