I appreciate that this thread was started. I can understand the desire to provide a new user with a good starting point with exposure. If we are talking about photography as art form, I have trouble with that as a long term solution. Every recommendation about film speed carries with it values proposition about what is important to the photographer. It, might, "maintaining maximum shadow detail is sacred." But very often the values proposition is left unstated and the conversation drifts off in to morass of technical machinations, as those there could be a scientifically derived formula of the best film speed apart from a subjective value system. If there can be a scientifically established "best" film speed, it is only the best in terms of certain aesthetic values. I find frustrating that this often treated differently than other parameters that are manipulated for artistic intent. What if a new user asked, "How many diagonal lines elements should I have in my compositions?" It would seem laughable that the would be pat formula for that. What if a new user asked, "What is best f stop and shutter speed to use?". If someone said, "f/8 and 125/sec are good, you should ALWAYS use them." I think most people would think that was silly. Almost everything can be manipulated for artistic effect. Some people intentionally burn and crack their negatives. There is a portrait photographer that says they like to use Tri-X 400 at EI 800. Oh, my god are they insane? They have everything totally controlled in the studio. Why would ever intentionally underexpose their film? Good heavens, some precious shadow details might lost forever in this mad approach. Why would they do such a thing? They do it because they like the look of it. Beyond giving beginners a reasonable starting point with speed, I don't grasp why, as they progress, this is much different than any other parameter for artistic intent or how it can have a universal objective answer. Artistic intent is what I find missing many conversation. Ansel Adam's exposure of of "Herandez" was a bit flawed in exposure and he went to great extents to remedy that like dunking the lower part of the negative in an intensifying solution. But it all because he had an artistic intent, he saw the potential in the scene. Brett Weston, unlike his father, often had images with deep shadows lacking in detail. Was because he was competent? Clearly not. It was because he was going for more abstract artistic effect that his father. If one twentieth of the effort put into arguments about the perfect film speed were redirected to helping others establish their artistic intent we would further ahead. Although newbies may say they have no artistic intent, often they do but can't state it. If they really do not ,they can be encouraged to look examples of great photography as see what moves them. Hopefully they can get a glimmer of intent. From there, they need to really experiment, just as music student must practice scales, playing with ALL the variables to understand how they work, so they can harness them to achieve their artist vision. So for film speed, they need go out and freaking practice and do shots with a huge range EI exposure/development times to the understand the effect of manipulating those variable so they can gain command of them to achieve their artistic vision.
