For those still interested in using a view camera, the BTZS Expo/Dev App is a great tool. It allows you to import film test data, which can be done with the help of Fred Newman at The View Camera Store in Fountain Hills, Arizona. Once the film data is imported into the app, your I-phone becomes a very accurate and simple to use calculator for exposure and development. It also calculates filter factors, bellows factor and adjusts the exposure for reciprocity failure. In addition, the app helps you set the desired depth of field and keeps a record of all pertinent data for each exposure in your I-phone. Further, the expo/dev screens prompt you so you don't forget to calculate for various factors which could throw the exposure calculation way off. In short, for the price of a lunch and a couple of days of film testing you can have perfect exposures every time. BTZS is a godsend and a no brainer for any serious large format photographer.

Expo dev finally ported to iOS. This app is a fabulous tool for BTZS users and zone system users alike. You will need your film data from the BTZS Plotter program or you can have the view camera store expose and test your developed film. My previous film data imported flawlessly into the program . If you are a large format photographer, don't leave home without it. I am thrilled with this program.

ExpoDev is truly a remarkable tool to have in the field. The app, combined with my personal film test data, has in a sense automated the process of large format photography for me. It has liberated me from having to worry about my negatives, so that I can direct my attention to the important process of making a photograph. With the ExpoDev app, a hard day's work in the field pays off in the form of an easily printable negative.