I found this 80 mm-200mm macro lens , and I thought to use for scanning my negatives and some macro photography , the problem is I can't get it to work at the minimum distance that is 12.5 in (31 cm) , I don't really know how to use it properly , any advise would help me a lot
Lenses like that often are labelled "macro" but are rarely properly described that way, because they almost never offer the flat field performance that true "macro" requires - particularly for scanning/film digitization. They probably should be described as "close focus" instead.
In addition, most lenses of that type only offer close focus ability at the long end of the zoom range.
Sorry to be the bearer of bad news, but I hope this is helpful.
You would probably be better off getting a good quality enlarging lens of the right focal length and adapting it to a bellows. Much cheaper and the lens is designed for flat field reproduction.
Adapter mounts for most popular size enlarging lenses are relatively inexpensive and available for most popular lens mounts, as are used 35mm bellows systems.
Lenses like that often are labelled "macro" but are rarely properly described that way, because they almost never offer the flat field performance that true "macro" requires - particularly for scanning/film digitization. They probably should be described as "close focus" instead.
In addition, most lenses of that type only offer close focus ability at the long end of the zoom range.
Sorry to be the bearer of bad news, but I hope this is helpful.
You would probably be better off getting a good quality enlarging lens of the right focal length and adapting it to a bellows. Much cheaper and the lens is designed for flat field reproduction.
Adapter mounts for most popular size enlarging lenses are relatively inexpensive and available for most popular lens mounts, as are used 35mm bellows systems.
The things that enlarging lenses are designed to do are extremely similar to what true macro lenses do - high magnification photographs of flat field subjects. Single purpose true macro lenses and enlarging lenses are often fairly lousy when used for more distant subjects.
The term "macro" is often (wrongly?) applied to lenses that are full of compromises, in order to permit use with both general photography and close work.