You may want to take some test shot to compare your photos with / without the variable ND filter. Filters (especially the cheap ones) can sometimes cause refraction that may soften sharpness and contrast.


But then I'm kinda confuse here. Generally, for an outdoor portrait shoot, the ND filter is used as the last resort to prevent overexposure of an image after we have maxed out the shutter speed (1/4000) with the lowest native iso (iso 100). And if the photo is still overexposed, then only we put in an ND filter so that we can continue to use a large aperture setting (for the nice bokeh effect) without overexposing the image. But if you are compensating light by boosting up your iso to 3200, why would you still want to use the ND filter anyway?

This post has been edited by garyeow: Apr 28 2019, 10:04 PM