Checking Filter Quality
You can check the flatness of any filter by looking through it with a telescope or one side of a pair of binoculars. The image should look unchanged, but even the most insignificant lack of flatness will look weird ort change the focus when magnified.
Hoya has been the world's largest maker of optical glass for decades. Not that anyone goes on record about this, but as far as I know, everyone, including Nikon, Canon and Leica, use some Hoya glass whenever they need certain types that they can't get elsewhere. Hoya also makes special-order glass when lens makers ask for it. Optical glass making involves a lot of trade secrets, so if Hoya makes something someone needs in a lens design, even if they know exactly what the glass does, they still can't make it themselves.作者: WuSoLo 時間: 2014-1-12 10:30 PM
我想在鏡頭保護片上各大牌子也不是差別很大，最緊要的就如 Mark 兄所說的和盡可能挑有多屬鍍膜就是了；還有如是超薄身的就更好！作者: sallytong 時間: 2014-1-13 11:46 AM
