I'm looking into Tiffen's matteboxable Multi Rota Variable ND, as a way to keep a more consistent aperture when shooting outdoors on days when the sun is constantly dipping in and out of the clouds. And I was wondering if anyone here has used it before, and can comment on their experience with it?
I built my own variable NDs for stills cameras back in the day (by combining off the shelf filters), so I'm well aware of the usual caveats of the cross-hatching. I'd love to hear some feedback on how the Tiffen MRT goes for colour cast though - if it has any? And if so, whether it's an issue?
Where the MRT strikes me as useful is used in conjunction with conventional NDs, so that you could set a base exposure with a combination of regular ND and the MRT set at 4-stops of compensation, and then you'd be able to open up two stops (it's minimum setting) if the clouds roll in, or close down two stops if the sun bursts out in all it's glory - all while keeping two stops down from the filter's maximum compensation of 8 stops, which starts to push towards the funkiness and cross hatching you can get when you take these variable NDs too far.
I think my theory is sound, but I'd love to hear from anyone who's actually put it to the test, and can comment on the unit's performance?