No. 3 Cartridge Kodak 

The No. 3 Cartridge Kodak is the smallest of the Cartridge Kodak family, taking 4.25 x 3.25 inch (about 11 x 8 cm) picures on daylight loading rollfilm. In the video on the left you see the No. 3 Cartridge Kodak with its usual film back. On the right the same camera with plate back set.
The No. 3 was introduced in April 1900 and dicontinued in 1907. It was never made with a wooden lensboard, like the 4 and 5.
The No. 3 Cartridge Kodak was an instrument for the more advanced amateur who could afford to spend a few dollars for a better class camera. The cheapest version with Triple Action shutter and Rapid Rectilinear lens cost $ 20. From there on several costlier shutter/lens combinations were available, ending at $ 72 for a Volute shutter and Tessar lens.
The camera in the videos belongs to a very complete set, with both backs, 3 double plate holders, a number of film sheet holders, ground glass, cable release and a leather case in which it all fits. The lens and shutter are not original, but fitted in about 1910. Plate backs were available for all three Cartridge Kodaks.
The Cartridge Kodak has a vertical and horizontal sliding lens panel, also the bellows could be extended for macro photos or telephoto shots. If you wanted to use these functions you needed to focus the image on the ground glass. Without it you could not focus properly and also not judge well what was on the photo and what not.

Ad in Photo Hall, April 1903. Original scan on www.collection-appareils.fr