An I.S.O is just a speed to start experimenting at and not written in stone, if 40 give you the the most acceptable results rate it at that, but it depends also on how you are viewing them they look different viewed on a viewer or light-box,than with a projector with a 150watt QI lamp. I find generally that the Fuji Pro range of films are all pretty accurately rated.
I realize that this thread is old and that Velvia 50 is no longer in production but I have to add my two cents worth.
First (this is a pet peeve of mine), you are not "over-exposing" film by changing the E.I. if the results are what you are after. I am amazed at how often the terms under-exposure and over-exposure are misused. For example, if you find that rating a film at it's box (ISO) speed produces dark transparencies, then you are under-exposing the film but you are not over-exposing it if you increase exposure by reducing the exposure index.
As for Velvia 50, from my experience, the vast majority (almost all!) large format photographers rate it at E.I. 40 or even E.I. 32. I do that as well. However, I have always found the 35mm version when rated at E.I. 50 to give me the best results in that format. But keep in mind that that can be due to different meters, shutters, etc.
I am surprised at how new film photographers are often afraid to rate film at other than the box speed. The box speed is simply a recommended starting point, that's all. The film manufacturer's will even tell you that. But some new photographers act as if the sky will fall if they change the E.I.
Also keep in mind that even if your meter and shutter is precisely calibrated and accurate, your metering changes everything. You could rate the film at it's ideal speed and then meter the scene improperly and get terrible results. This is fundamental.
What struck me about the original question is that David says that he found that he was getting better results at E.I. 40 but he isn't sure if he is ready to rate the film to E.I. 40! What's the issue? If you are getting better results at E.I. 40, switch to ISO 40. Your eyes are telling you that it's better but you were still (when you wrote this long ago) unsure whether to go with what you could see for yourself with your own eyes!!!??? David, your tests told you all you need to know. Why would you hesitate to rate the film at the speed that gives you the best results.
One more technical thing: When you rate a film at other than it's box speed, you are not chaning the ISO. In other words, if you rate Velvia 50 a E.I. (exposure index) 40, it is NOT ISO 40. ISO only refers to the box speed. When you use a speed other than box (ISO) speed, it is then referred to E.I. E.I. is the TRUE speed of the film for you with your equipment determined by testing.
There are almost no films that I rate at the ISO speed. Knoweledgeable photographers have no qualms at all and do not hesitate to test their film and rate it at whatever produce the best results. For example, I rate 100Tmax at E.I. 64, Tri-x sheet film at E.I. 200, Tri-X roll film at E.I. 250, etc. Those are NOT over-esposing the film. In fact, if I rated them at their ISO (box) speeds, I would be under-exposing them.
I just had to respond so that someone else who is unnecessarily agonizing over whether to rate a film at a speed other than the box speed will not heistate to do so. Again, the box speed is just a starting point and nothing more.
BTW, I have found that for me, with my lenses and meters, Velvia 100 performs best at about E.I. 125 but that's just me.
Hi ZoneIII, they still make Velvia 50, at least in the smaller formats. Unless of course you're referring to the original Velvia, which Velvia 50 replaced.
I too shoot Velvia 50 at EI 50 and Velvia 100 at EI 125.
Whether you want to call it ISO, ASA, or EI, it doesn't matter to me, but I agree that you shouldn't be afraid to experiment and expose your film the way that works best for your particular look.
Fuji Velvia 50 has been discontinued again in July Last year http://www.bjp-online.com/british-jo...essional-films
Originally Posted by LJSLATER
As that article states, Velvia 50 is still being produced in 35mm and 120, but was discontinued in large format. Velvia 100F has been discontinued in all formats, but existing stock is still available.
Originally Posted by benjiboy
Sorry on second reading you are right I misinterpreted it.
Originally Posted by Stephen Schoof
You can tweak exposure a tiny bit if you prefer how it looks. The more relevant question would be, how
does the final output (like printing) like it? Or are you doing this just due to a metering oddity? The
related question, whether to "pull" process it, is via my own testing, a waste of time. There is very
little forgiveness in this film for that kind of thing. The older Provia II pulled well, as did both generations of Astia, but none of these newer Fuji films, or any Velvia. The limitation kinda comes with
the territory of high contrast and high saturation.
Velvia at EI40 is for contrasy scenes, not the intended diffuse illumination that the film was designed for. At moderately short (<1 sec) EI40 will lighten shadows, but will also blow highlights easier. It is a risky thing to do and most risky with cameras using evaluative/multipattern/matrix meters because they do not provide implicit bias to elements (individual luminances) as a manual spot meter would. Ideally, meter the scene with a spot meter (Hi/MID/LO/AVG) at box speed (ISO50); nailing the exposure in the right light is very easy and produces beautiful, beautiful images (more difficult with 35mm, but it can be done, and done well), then even more startling when printed (by whatever means, either darkroom or digital). If people are getting blocked up shadows, grossly blown highlights and the like at EI32, EI40 or ISO50, the film is not being exposed correctly. None of this is a secret. All of the Velvia films (including the pasty 100F and bold 100) require diffuse lighting. Provia 100/100F is Velvia with a reduced primary palette spread and better shadow tolerance and highlight control. It is preferred in illumination that is not or could potentially throw Velvia off.