One foreword about formats:

5x7 inches and 13x18cm are different film sizes and need different film holders. Film holders, at least the ones from Linhof, in both sizes, fit in a common ground glass back.

4x5 inches and 9x12 cm are different film sizes and need different film holders. Film holders from Linhof and also Graflex, Fidelity and many other makers, in both sizes, fit in a common ground glass back.

That means: the camera is the same, one only has to match the film and film holder and use the same camera back, ground glass. In this text I will use the cm as unit, so I will mention only 9x12 and 13x18 formats.

This is maybe too big for hand held photography, but the concept of these dropping bed cameras, having a coupled focusing device, viewfinder and a handle (all of them not present in mine), was clearly intended for that. Well, I only use it in a sturdy tripod and framing/focusing on the ground glass. Photographers had more muscles at those bygone times.

Anyway, for studio or field work, provided one uses a tripod, the set up of a camera like this is by far easier than a kardan model. It allows less movements but not everybody does extreme perspective corrections all the time.

Quality is excelent, everything done to last forever. The format 13x18 is not that popular. It is harder to find enlargers able to handle it. When I shoot in 13x18 I do contact printing and it is a very good option for alternative photography when using sensitive material that needs UV light and cannot be done in a enlarger. There is an interresting article considering the pros and cons of 13x18cm (or 5x7 inches) at the   Large Format Photography pages.

It is very useful having an original reducing back from 13x18 to 9x12. The Technika 13x18, while shooting in 9x12 allows a lot more movements and belows extension. As a matter of fact, had I bought first the 13x18 with a reducing back, I doubt I would go for a second camera in 9x12.