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The ND values of the three filters are different. In order to avoid the phenomenon that the wide-angle camera and the medium-telephoto camera are properly exposed and the telephoto camera is under-exposed, the light reduction values of the three lenses are slightly different. For example: ND8 for wide angle, ND8 for medium telephoto, ND0 for telephoto ND16 for wide angle, ND16 for medium telephoto, ND8 for telephoto ND32 for wide angle, ND32 for medium telephoto, ND16 for telephoto Wide-angle ND64, medium telephoto ND64, telephoto ND3 The ND & PL filter is also the same as the ND value distribution of the ND filter 

Dear Customer, so sorry to tell you that this adapter won't allow your nikon 1 s1 lenses to mount to my canon t2i. 

I would think that it would be no problem, as long as it has a 1/4-20 threaded mount on the camera. I might suggest looking for a video tripod, though, over one designed primarily for stills cameras. A video tripod will give you smoother control over panning and tilting maneuvers. 

yes, the flash can work on Canon 7D