Variable ND filters how good are they?

[Freelancer]

are they worse then fixed ND filters?

i dropped my 10 stop filter and now i need a new one.

im thinking about buying a variable filter but if the quality of fixed ND filters are visible better then i go for the standard model.

any first hand experience?

 

[Loswr]

Tried a FaderND, IQ takes a noticeable hit. If you're going to go the vari ND route, I'd go Schneider/B+W or Singh-Ray.

Even with the top quality ones, there are problems at an AoV of wider that 24-28mm (on FF). A vari ND is basically a pair of stacked polarizers, and just like a CPL results in uneven polarization at (ultra) wide angles, a vari ND has a 'Maltese cross' effect that gets worse the wider the angle and the darker the setting.

 

[Standard]

Tried a FaderND, IQ takes a noticeable hit. If you're going to go the vari ND route, I'd go Schneider/B+W or Singh-Ray.

Definitely go with the Singh-Ray if you're going the variable route, either with the Vari-N-Duo or the Vari-N-Trio. I'd go with the slim versions to avoid as much vignetting as possible. Be aware that even with a slim version at around 24mm you will get some vignetting regardless if you're using a prime or a zoom lens on a full-frame camera. There are dozens of pros out there that swear by these. Personally, I returned my copy of the Vari-N-Duo and use instead B+W and Lee ND filters. I find them much easier to use when it comes to predicting end results. The Singh-Ray filters, even though they have dial markings on the lens does nothing to indicate any true usefulness.

You'll find excellent image samples here along with the photographers that use them at Singh-Ray blogspot:
http://singhray.blogspot.com/
http://singhray.blogspot.com/search/label/Vari-N-Trio
http://singhray.blogspot.com/2008/10/good-day-at-black-rock-with-new-vari-n.html

 

[Loswr]

Depends on your use. I'd say for outdoor portraits using a fast prime wide open, a variable ND might be a good choice. The higher end ones will not have a significant negative impact on IQ. But for long exposure landscape shots, where you might be using a wide angle, I'd go with the standard NDs.