I'm not filmilar with the Micro Nikkor but if it is like the 55mm Vivitar macro I have it will have a magnification scale on the lens. Lets say the Fuji Instax image is 3X4.5 in. In that case the scale would be set at a bit less than 1:3 That is if your Nikon is a full frame camera. If it is a APS sensor then the ratio would be about 1:4 or 1/4 life size.
Look for a scale on your Nikkor that has several markings such as; 1:10 1:7 1:4 1:2 etc.
First, do you have a full frame digital or APS size sensor? You need this information to caculate what ratio you need to set to fill the frame. Then set that ratio on the focusing ring and move the entire camera back or foward until the image comes into focus. If you find that is too close then back up, just a little, and refocus until the image is sharp. If, on the other hand you find the image is not quite filling the frame then move in, just a little, and
refocus. Obviously with 6X6 square negatives then some of the frame on the sides will not be used when making a copy.
Clear as mud?[/QUOTE
I am using a Fuji X-E1 so it is APS. I have read that 1:1.5 is the ratio need for coverage.
The lens does have the markings for both with and without the PK-13 tube so now that I know that I will use the info to compute the ratio needed. I was trying to eyeball it but that is a moving target. Focus, move lens, focus, move lens ad infinitum. I am slowly learning this macro thing. YouTube has not been much help so far. Mud? No but dishwater, maybe.
John