Speed Magny 45, Speed Magny 100 Manufactured by Mikami Co. for use on Nikon F camera bodies with original back removed. Speeed Magny 100-2 for use on Nikon F2 camera bodies with original back removed. Model 45: Produces a 4x5 inch image size using Polaroid Land Film Holder 500 and type 57 film (according to original specifications; any4x5 sheet film that fits a Holder 500 will also work). The Film Holder 500 is not included and must be purchased seperately. Model 100: Produces 3.25 x 4.25 inch image size using Polaroid Land film type 107 (or any Polaroid Pack film type of the same size). The pack film holder is built-in, no additional film holder needs to be purchased. . Designed primarily for news work, it was also effective for sports, wildlife, traffic control, law enforcement, aerials and construction engineering. The image is magnified by a factor of 4.1 with the Model 45 and 3.2 with the Model 100. This gives an effective focal length of 820mm when using a 200mm lens and the Model 45, or an effective focal length of 640mm when using a 200mm lens and the Model 100. Zoom lenses can also be used. Even though lenses shorter than 200mm may be used, slight vignetting and image degradation around the edges of the image may occur. Also please note that there is a great deal of light fall-off when using the SpeedMagny. For the Speed Magny 45 exposure factor is 20, for the Speed Magny 100 exposure factor is 18, or roughly 4.5 to 5 stops for either model.