Complex sentence: It is actually more appropriate to use the close-up lens terminology as it is a lens and not a filter, although close-up lenses typically mount on the filter thread of the primary lens, and are manufactured and sold by suppliers of photographic filters.
Split into simpler sentences: It is actually more appropriate to use the close-up lens terminology as it is a lens and not a filter. Close-up lenses typically mount on the filter thread of the primary lens, and are manufactured and sold by suppliers of photographic filters.