will end sept till early Nov be good? I understand is Spring and I wanted to visit South Island with my wife but she's not a photographer so just self drive photography tour. Likely won't take the Milford trek as it sounds daunting! LOL
Actually I think end sept will be better. There will probably be no snow at ground level but most of the mountains should still be snow capped and very beautiful.
note that some of the mountain ranges are not very tall like the remarkables so once the snow melt finish, they look REALLY ugly. I have been to queenstown in summer and winter and winter by FAR is the better looking one.