What are the common points between 6x9, 24x36 and APS-C sized sensors? They all are or have been the most popular formats of their time for quality cameras and they all share the same aspect ratio, i.e. 3:2. Why is this aspect ratio so successful? Because rectangular pictures with a rather elongated format have always been in fashion. Traditionally, painters used canvasses whose dimensions were based on the golden ratio, because the golden rectangle has been considered aesthetically pleasing since Luca Pacioli's book De Divina Proportione, which was published in 1509. Of all common photographic formats, the 6x9 format's 3:2 aspect ratio is the most similar to the golden ratio (1.5 vs. 1.618).
The 3:2 aspect ratio is very well suited to many subjects. It is wide enough for landscape when used horizontally. Vertically, it is ideal for portraiture or full body photographs. It is also great for printing on most common paper sizes: either the standard 10x15cm (4x6in.) "postcard" size or the normalized ISO series (A4 paper, which is 21x29.7cm, has an aspect ratio of 1.41).
The 6x7 format, which was touted by its promoters as the "ideal format," gained popularity in the 1960s and 1970s and eventually replaced 6x9 as the rectangular format of choice on 120 film. Except for some 6x9 backs adaptable on multi-format cameras, there are no more 6x9 cameras produced today. But there is a treasure trove of vintage cameras waiting in our attics. Most of these old cameras are still very capable of taking great pictures today and the 120 film that most of them use is still widely available. A 6x9 image can offer a tremendous amount of detail: scanned at 2400dpi (a rather low resolution), it will yield a 5820x7944, i.e. 46Mpix image.
It is important to note that the common format denominations, like 4.5x6, 6x6, 6x7 and 6x9, do not correspond exactly to the size of the image in centimeters. Worse, these sizes tend to vary from one manufacturer to the other. The usable width of the negative for 120 film is 5.6cm. If we look at the 3:2 aspect ratio, we can see that the length of the 6x9 image should be 8.4cm. In fact, the length varies between 7.8cm and 9cm, with many cameras being in the range 8.2 to 8.5cm.
Musashino Koki Rittreck/Optika II-A
Royer Altessa, the First Interchangeable Lens 6x9 Rollfilm Camera
Fujica G690 Series Cameras
©Sébastien Lallement 2005-2011 - All rights reserved.