Feature: 1. Combination Frame: Adjustable reducer frame is a combination frame, rotating frame can drive the lens to do relative rotation, so as to achieve the effect of adjustable ND value, rotating frame we can see the lens from light to dark change. 2. Recommended Range of Use: The adjustable filter is the use of 2 CPL superposition principle to achieve the purpose of adjustment, the recommended range is ND2-ND400, high density segments such as ND1000,ND2000 can not be done. 3. Scale Familiarization: When the adjustable filter is used, it is necessary to be familiar with the lower scale range, on the lens, facing the sky or a brighter place, start from min to maximum, pay attention to the color change of the viewfinder, and write down the scale of this position when the uneven dimming appears at the beginning. 4. Long Exposure: This scale is the slow door switch position, and the scale range behind it must be exposed to eliminate the "shadow". X shadow and high density segments generally require a long exposure of more than 4 seconds to eliminate the more obvious dimming uneven situation. 5. Morie Fringe: Uneven dimming non quality problem, is the situation of moire fringe, through sufficient time of long exposure "X" shadow, light can be eliminated. Maximum position is the limit position, close to ND1000 obviously can not be used. 6. Optical Glass and Aluminum Alloy: The adjustable ND lens filter adopts shock proof tempered optical glass and aluminum alloy frame, which is extremely long lasting and almost unbreakable. Specification: Item Type: Adjustable ND filter Material: Optical Glass, Aluminum Alloy. Package List: 1 x Adjustable ND Filter 1 x Storage Box