Strange problem w/ 100-400 Z lens - SOS

[Wes Peterson]

I make a 120mm long hood too. The 120 doesn't vignette at any focal length which makes the HB-103 petal-style design a real mystery. No clue why they would design a hood like that for the lens, unless they consider it more of a fashion statement than a functional hood.

Maybe you should check corner sharpness at 100mm

 

[zemlin]

Maybe you should check corner sharpness at 100mm

My gut response to this ... I wouldn't expect diffraction to be an issue before vignetting would start to set it, but I didn't want to respond to speculation with speculation.

I contacted the owner of the lens I used for the design. As luck would have it, he opted for the 120mm hood. He's a retired professional shooter who loves to dig into technical details, so I trust his feedback.

I asked him to setup a test shot to check corner sharpness at the shorter focal lengths with and without the hood.

I've done the test at 100mm, 135mm, 200mm, 300mm and 400mm, all raw. I see no difference at any distance at 100%, hood or no hood.