Hoya Variable ND Filter

[Vortex]

I tried a new Hoya 3-400 ND filter on a GH4 whilst videoing for the first time last weekend and after watching the playback it has darkened the left and right of the image leaving the inner 3/5ths a lot brighter.

I've never seen this before...Has anyone else??

 

[kloner]

you really gotta be careful with variable nd's. the variable are a par of linear cp stacked that as are rotated makes different darkness, well they get what you mention in certain orientations. you gotta find the sweet spot of the filter and keep it orientated that direction. We've found it takes gaff tape over the whole thing to keep them from rotating while flying. there kind of a pain, i like the hoy regular nd, usually lenses always need the same stack or as sun goes away just gotta take em off.

we recently had a run in with this and it sucked.

 

[Vortex]

Thanks Kloner.....I knew someone would have had the same problem. The rotating ring is very loose and I considered sticking it with tape to hold it in place too!!! I had it wound up fairly high so I might look for a fixed ND and keep this one for whan I am desperate!!!

Luckily we were only out on a practice shoot and weren't shooting for a client or we would have been in deep ****!!!