Another incentive for increasing sensor area is resolution. For a given pixel size, a larger image sensor area means more pixels, and therefore more image detail (pixel size trade-offs wil be discussed in "Digital Photography Essentials # 2, Pixel Size"). Figure 4 shows a list of common optical format sizes and associated applications. The largest format size shown in figure 4 is the 24 mm x 36 mm size used in "35 mm" film cameras. It is interesting to consider whether the popular 35 mm optical format will survive the transition to digital, or whether a new format, such as the 4/3 inch format, will emerge to dominate in the age of digital photography. A smaller format would allow for lighter and cheaper lenses, with the same field of view, depth of field, and other optical characteristics as the historical 35 mm family of lenses.
Because there are so many ways things can go wrong with making prints from film, especially from print (negative) film, beginning photographers and hobbyists usually get better prints from digital because there are fewer variables to control.
To quote from Peter Ensengerger, Arizona Highways Director of Photography, in that most recent article: "digital still can’t touch large-format film for the full-page reproductions that have made Arizona Highways famous" and "The 4x5 view camera remains unsurpassed for landscape photography."
For most things digital is far more convenient if you're shooting hundreds of images, making prints smaller than a few feet on a side and posting on websites and email, and for other things like landscape photography for reproduction and large fine prints film is better.
[This article was originally a study guide written for 7th and 8th grade math students for a mini unit on photography and math. It incorporates many concepts taught in middle school math including some basic algebra, fractions, decimals, ratios, sequences, area of a circle, metric measurement, and measuring angles. Students had been taught all of these concepts before the unit. This unit helped them apply that knowledge to a real world setting. Students had a chance to experiment with vintage 35mm single lens reflex cameras. While the students worked with film cameras, all of the concepts apply to digital cameras also. While not covered in this article, middle school math is also abundant in additional digital photography concepts such as the pixel dimensions of the image sensor, the total number of pixels, and the aspect ratio of sensors. It is a very challenging unit for middle school students. The article is therefore also appropriate for adults. Many of the math concepts in photography are skimmed over in introductory photography texts. In particular, there is usually not a full explanation of the mathematical meaning of f-stops.]
In digital SLR cameras, the term 'focal length multiplier' is often used to describe the size of the capture area of an electronic image sensor, relative to the traditional 35 mm film capture area, which is 24 mm x 36 mm. For example, a digital camera with a focal length multiplier of 1.7X has an actual imager size of 14.1 mm x 21.1 mm. If a digital camera with a 1.7X focal length multiplier is used with a 50 mm focal length lens, it will have the same field of view as a 35 mm film camera with an 85 mm focal length lens. For a photographer making the transition from film to digital, this can be a problem because all of his familiar lenses will effectively have the focal length multiplied by 1.7X. If the photographer does not already have lenses that can achieve the desired field of view with the smaller sensor field, new lenses must be purchased, adding to the cost of entry into digital photography.
While this is a long paper, we have really just touched the surface of studying photography and math. For example, we have not discussed film processing and printing, or digital image manipulation.