我发给香港老蔡的贴子不知你看了没有。
我发现我的508有严重问题。在寄回香港前想麻烦你，同你的机器作最后比较，不知可行否？
急盼回复！
I heard a way of sun F16 from Xitek, you can have a try: wait for a sunny day, without cloud in sky, use you camera to catch the blue sky( don't include sun, you'd better put the lens at 90 degree with sunshine), set the aperture at F16, the shutter speed shuld be about 1/125.