Interesting phenomenon with Cokin vs Hitech ND grads

[Canon Balls]

Basically the Hitech ND grads react with the polarizser. I'm not sure if they are intended to be used together, and if not, why so many slots on the Cokin system?

Anyway, I thought it would be easier to make a video.

[youtube]kri-vL-oB3w[/youtube]

 

[markmullen]

Strange.

I use the same setup, Kood P Series CPL and Hitech ND grads and have no problems, this was taken with that setup, 3 stop ND soft grad and CPL.


1967 Aston Martin DB6 by mark_mullen, on Flickr

 

[Canon Balls]

so what's causing that on my filters?

 

[dinners]

I think some materials used in filters can de-polarise light which can cause some strange effects.

That said - I've used Hi-Tech soft grads infront of a Circular Polariser and haven't noticed anything strange.

How does it appear on a photograph compared to looking through them at your screen display ?

 

[photon]

How does it appear on a photograph compared to looking through them at your screen display ?

Yup, isn't this a moiré pattern due to looking at a screen?

 

[Canon Balls]

I'll give them a try outside later and let you know what the results are like. I'll do a few A/B's of the same subject