It is a very, very straightforward and just about fool-proof method to get everything on Velvia if you are shooting in the light conditiions for which it, Astia and Provia were designed diffuse spectral. If you want to expose this film in bright light with deep shadows and blinding spectrals, expect trouble and don't consider that the Zone System will be there to get you out of the bog.
Meter shadows, but not pure black. Meter light tones, but not pure whites (or bright spectrals e.g. in water); add in a mid-tone (any number of times) from the scene, and average it all. A reading of + or 3.5EV is in the ballpark of correct exposure for Velvia when all tonal differences have been accounted for. Nobody should be metering spectrals because, as MattKing said, it will result in a mid-grey reading, potentially flattening the entire scene (and doing nothing for shadows into the boot). We are concerned with highlights and shadows, true, but not those areas where we know will lose detail. Additional tweaking for time value is usually required in the case of flowing water where spectral areas will, if you know from experience, not tolerate an extended Tv value; that is to say, the longer the Tv, the greater the chance of highlights blowing out and losing all detail in the water (which is essential to express its aesthetic character).
I recommend beginners starting off with Velvia steer well clear of any discussion that happen across about the Zone System applying to Velvia. It doesn't help their or the film's cause. The emphasis is on commonsense, experience, trial and error and understanding the subject matter and prevaling light. Leave the Zone System to monochrome where it is a great deal more useful.
Meter shadows, but not pure black. Meter light tones, but not pure whites (or bright spectrals e.g. in water); add in a mid-tone (any number of times) from the scene, and average it all. A reading of + or 3.5EV is in the ballpark of correct exposure for Velvia when all tonal differences have been accounted for. Nobody should be metering spectrals because, as MattKing said, it will result in a mid-grey reading, potentially flattening the entire scene (and doing nothing for shadows into the boot). We are concerned with highlights and shadows, true, but not those areas where we know will lose detail. Additional tweaking for time value is usually required in the case of flowing water where spectral areas will, if you know from experience, not tolerate an extended Tv value; that is to say, the longer the Tv, the greater the chance of highlights blowing out and losing all detail in the water (which is essential to express its aesthetic character).
I recommend beginners starting off with Velvia steer well clear of any discussion that happen across about the Zone System applying to Velvia. It doesn't help their or the film's cause. The emphasis is on commonsense, experience, trial and error and understanding the subject matter and prevaling light. Leave the Zone System to monochrome where it is a great deal more useful.
