This holder is especially made to mount on the Olympus 7-14mm F2.8 lens, and can be used together with up to two square filters. There will be no vinjetting at all, in upright and 90 degrees of use even at 7mm wideangle.
But you will get some vinjetting in the corners if you use it in 45 degrees rotating and with 7mm focal lenght.
NiSi Filter Holder 100mm For Olympus 7-14mm F2.8