I understand that XC lenses do not have an aperture ring. Suppose I mount such a lens on my X-E1, and want to shoot on Aperture Priority, how then do I set my Aperture ? Thanks in advance for your help. Fyi, I'm still hesitating between the XF 55-200 and the XC 50-230. There is certainly no doubt that the 55-200 IQ is far better, but I also consider the price and the weight.