I bought a Calumet 7X loupe to help with focusing on the GG. The rear element can be turned one complete circle to lengthen the overall length of the loupe. What is the function of this feature?
I've observed that when the loupe is at its longest length, the image on the GG appears blurry and grainy. When the loupe is at its shortest length, the image on the GG is sharp and grainy. The grains belong to the GG right?
The loupe didn't come with a manual.