Breakthough 100mm filters in Lee holder

[bitm2007]

Hi

Does anybody know if the Breakthrough Photography 100mm X4ND square filters (6 or 10 stop) are fully compatible with the Lee Filter Holder ? They don't appear to have a foam gasket, so I am concerned about light leakage.

 

[bitm2007]

I got the following reply from Breakthough

Our Square NDs have foam around the perimeter. Not sure if there is a Holder that is 100% free of light leak. Our filters are standard 100*100*2mm.

Has anybody tried a Breakthrough 6 or 10 stop 100mm X4ND square filter in a Lee holder ?