SLR Magic Variable ND Filter 0.4-1.8 Mark II (77mm) brand_Nikon you can also use this

you can also use this lens as a totally normal short telephoto lens for portraits

it's still a Holga lens

2 Manfrotto 052 stands

Individually-adjustable pan and ball controls

Good quality 48mm filters from various brands

SLR Magic Variable ND Filter 0.4-1.8 Mark II (77mm) brand_Nikon you can also use thisThis SLR Magic Variable ND Filter Mark II is specially designed to minimize the weird uneven vignetting that sometimes afflicts variable filters. How? Using "special glass and treatment." Not sure what that means, but it seems to do a pretty good job. ND range is from 0. 4 to 1. 8 (just over 1 stop to about 6). A bit bulky it's thick, and the outer thread is 86mm but this filter includes its own lens cap to make up for at least the last bit of that.