Quote Originally Posted by DrPhil

The zone system is so elegant and simple. Why would I want to complicate it by carrying a PDA with exposure software? With the zone system I can meter the shadows and the highlights, calculate the exposure and development, adjust for filters and/or bellows, and take the picture. I can do all this in my head, what could be simpler?
There is absolutely nothing elegant and simple about the Zone system in my opinion. The trial-and-error testing procedures used to determine effective film speed and development time are extremely laborious, and they must be repeated for subject lighting conditions that require expansion and contraction development. And second, the results, which are evaluated by visual comparison, are somewhat arbitrary because all visual comparisons are inherently subjective in nature.

BTZS testing, which relies on sensitometry, is capable of providing much more useful data about our films in far less time than the trial-and-error testing that has been traditionally used with the Zone System. A couple of hours testing film with the BTZS system can provide a photographer with virtually everything he or she needs to know about exposing and developing film for the specific requirements of a given process, regardless of the lighting conditions of the subject. Acquiring an equivalent amount of information by trial-and-error procedures as used for Zone System testing would by contrast would take many days.

Another consideration is that the data you collect brom BTZS testing can be used for both the SBR Incident system of metering, or with a spot meter with the Zone system. Zone system data, ion the other hand, is useful only for reflective metering. This is important for me because I generally prefer incident metering there are times when Zone system metering will give better results.

BTW, the fact that one uses BTZS does not mean that you always teake very extensive field notes about lighting conditions and expose and develop every sinlge negative according to a formula. To the contrary, once you have become familar with the system it is every bit as intuitive as the Zone system. The ExpoDev program, for example, while extremely accurate, is certainly not necessary for the majority of lighting conditions. I myself only use it for very complicated lighting situations that involve reciprocity and/or filter adjustments. In these cases I trust it much more than my own calcluations. For the majority of situations I simply calculate the SBR of the scene, meter in the shadows and make the negative. Takes less time than Zone metering and is much less subject to gross operator error.

Sandy King