Please, explain me this. Does this lens have auto diaphragm, i.e. the camera measures at open aperture and it closes automaticaly when it shoots (like it was with FM-3a and AI or D lenses or with AI lenses on, say, F100), or the photographer has to close it manually? Which of exposure modes work with bodies like D700, D7000, D300s and the Samyang 85mm on? On official site of Samyang I haven't found the explanation. Regards.