Mamiya 5.5x Magnifier for C series brand_Calumet A very early example: this

A very early example: this lens was made in 1954

so non-camera things might actually be a better idea at this point

Each sheet holds 4 negatives

this lens also has a pretty respectable f4 constant aperture throughout its zoom range

if you're willing to put the time in

Mamiya 5.5x Magnifier for C series brand_Calumet A very early example: thisThis magnifying accessory slips on top of the waist level finder and provides an adjustable 5. 5x magnifier, ideal for precision focusing. In excellent condition, with only minor cosmetic wear. Includes softcase and box. This accessory requires a standard waist level viewfinder, which is not included.