Hi all,

I'm looking at buying a 4x4" / 100mm square,. 13 stop / ND3.9 filter for an upcoming project, and am wondering if the Formatt Firecrest Ultra filters fit the Lee holders and hoods?

I see that both brands use 2mm thick glass, so think that should be no problem. I'm wondering also however about the gasket, and if the one included on the Formatt filter can be accommodated and forms a good seal when used with the Lee holder. I'd just a soon buy a Lee product, but they don't have a 13 stop filter, just 10 and 15 stop. I'm looking to do some ultra long exposures of around 8-12 hours, and think the 13 stop filter is probably the best starting point.

The other option is to go with a circular filter, but I'd prefer to be able to use my Lee hood.

Thanks in advance for the advise!

Tim