I've been using an Ebony 45SU for several months with the standard GG setup. It has a Fresnel sandwiched between the GG and a protective glass. I've noticed that it is difficult to position NDG filters accurately based on visual inspection of the GG. I am wondering if part of the problem is the Fresnel. It seems that as the dense portion of the filter enters the frame that the reduction in illumination is partially spread across the entire frame making it difficult to discern where the transition is. Right now my work arounds involve positioning with a 0.9 NDG filter with the lens stopped way down and then swithching it out for whatever strength NDG I really want to use. Positioning the filter while viewing through a loupe also helps a great deal. Does anyone know if fresnel screens encumber NDG usage? If not any advice on technique would be appreciated.
Thanks
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