Hello, the most important question you pose, the exposure range, is often a debate in the Internet forums, although it is clearly answerred in the datasheet that you can download from the Fuji website!
Just learn how to read the characteristic curve -- on the X axis, there is the exposure, 0.3 being one f/stop; going to right means more exposure. On the Y axis, there is the resulting density from that exposure. When the curve is going downwards steeply, the tonal separation (contrast) is high -- this is called the linear region. Or "almost linear region" -- it's up to you what you want to read from the curves!
This almost linear range is around 6 to 7 stops with all Velvias; Velvia 50 may show a little bit more than 100 and 100F, but not much.
OTOH, when the curve is straight horizontal line, every detail is lost. But, with slide film, the toe and shoulder are very important. This means the parts of the curve that do not produce full tonal separation but still show detail. Velvia 50 can show some detail for even up to 10 stops, but Velvia 100 and 100F are worse in this regard; they have sharper toe and shoulder.
A basic "rule of thumb" often stated is that it's good to have sharp toe and shoulder, but this is based on the comparison where longer toe and shoulder would eat off the linear part. (And this is mostly the rule for designing color negative films, where the toe and shoulder are ignored anyway). This is not the case with Velvias, as the 50 shows as much linear part as 100 and 100F, if not even more. Therefore, the longer toe and shoulder are merely extra. In practice, this means that the Velvia 50 does not block the shadows as easily as the newer counterparts, but still show the nice high-contrast crispness in the midtones. I'm also seeing better highlight detail with Velvia 50.
The color rendition is completely a different matter from this. I won't go into it because it is always well discussed whereas the contrast or "dynamic range" issue is dismissed.
I have evaluated pull processing of Velvia 50 in a controlled side-by-side test and found that shooting it at 20 to 25 ISO and developing for 2 minutes less than normal in FD results in decreased contrast, decreased color saturation and increased tonal separation in both shadows and highlights. The effect is not huge but it's clearly there. I liked the results more than when shot normally. Has anyone tested this with Velvia 100 or Velvia 100F? I think it would be even more important with them to tame the contrast.
Last edited by hrst; 06-18-2011 at 01:44 PM. Click to view previous post history.