In our bright summer sunshine, one needs to use ND to bring Super16mm film lenses outside of the aperture settings where they will yield diffraction artifacts in the image. Super16mm "ultra" lenses also tend to favour wider apertures. They were designed to do so in order for the image to more closely resemble 35mm format lens images as to shallow-ish depths of field.

Using heavy ND risks infra-red contamination in the image in many video cameras.

The Tiffen IRND1.8 filter enables the SI2K to operate with "standard" shutter speeds with lens apertures set in the T2 - T4 ballpark in our bright summer outdoors.

Here is a link to a bit of practice filming I did to learn to use the IRND1.8 filter. The colour grading is a bit off because I am partially red-green colour-blind. There is a greenish cast to the unprocessed image and the green must be pulled down a bit in grading. The greens seem more faithful and greens in shadows seem to reproduce more faithfully.

ROLEYSTONE CRICKET CLUB IRND1.8 AND LENS TESTS - YouTube

HEATH MEAD. - ( IRND1 8 PLUS UNLTRACON3 FILTERS ON SI2K CAMERA TEST ) - YouTube

Youtube in its infinite wisdom seems to be doing a bit of internal resource conservation in these days of monetisation. The clips will not replay. One viewing is all you get unless you reload this page.

It seems I might need to eat a bit of crow. The clips which for a few days would not replay, now do replay.

So my apologies to YouTube who seem to have resolved the issue.