ExpoDisc 2.0 Professional White Balance Filter - 77mm Category_Tripod Parts & Accessories And what are all these

And what are all these things that I see advertised as indispensable photo equipment really for

it is perfect for zoom lenses that can vary from wide to telephoto

but they are all on the move

a three-holed screw mount to fit an optional stay and grip

those moving at random speeds and those approaching the camera at high speed

ExpoDisc 2.0 Professional White Balance Filter - 77mm Category_Tripod Parts & Accessories And what are all theseExpoDisc, the original white balance filter gets even better. Set white balance, meter for exposure and dust map your sensor with the only calibrated and certified 18% transmission incident light metering filter.