That's interesting - I got my figures by looking at the characteristic
curves of some Kodak films - see for example
(royal gold 400) and comparing with some slide film - see for example
(PROFESSIONAL EKTACHROME Film E100VS).
I looked at the characteristic curves, and the exposure density range on
the bottom axis corresponding to a more-or-less linear part of the
curve. For slides I got a density range (log) about 1.6 and for negs
around 3.3 corresponding to just over 5 stops and 11 stops respectively.
Perhaps in your measurements you went beyond the linear part of the curve,
which is valid if you can still see the difference. This fits with the
given curve because 7 stops corresponds to a log density range of 2,1 which
is in fact the range given on the curve when you include the more curved
parts at the end. You should have noticed some compression at the limits,
and from the curve I am looking at, a tendency to red at the extreme dark end.
On the same basis you'd get 12 stops out of neg film.
I was told at my recent classes by a "pro" that slides had a range of 4
stops, and negs 7 stops which are the figures he used in his zone
thinking. Perhaps he was being conservative and allowing for inaccurate
exposure.
I cheerfully admit to not really understanding the zone system, but I can
well understand the simple concept of a 5, 7, ... 11 stop range and how to
fit what you want out of a particular high contrast scene onto your film
with a spot meter.
Julian
Regards,
Julian
At 15:52 23/11/01, you wrote:
>I think the brightness range of transparency films has improved a lot over
>that. 15 years ago, I ran some zone type tests with transparency
>(EXTACHROME should any one care). Essentially, I metered a evenly lit,
>evenly toned surface ( a gray garage door for me back then). The meter
>wants to reproduce this as ZONE 5. I then did a range of under and
>overexposures, in half stop increments. You want to learn three things:
>
>1) does your meter reproduce this image as 18 % gray (Zone 5).
>2) when do things get as white as they can get (film base + fog)
>3) when do things get as black as they can get (max D)
>
>What I learned was that I needed to boost film speed by a third of a stop,
>and that EXTACHROME had a range of 7 stops. I was able to use that
>information to shoot effectively.
>
>I then stopped shooting for a couple of years as I had small children and
>they left little time for creative activities. I picked up my cameras again
>in earnest, 2 years ago. As film stocks have changed a lot, I repeated the
>same tests on both KODAK and FUJI emulsions. I was surprised to learn that
>the film speeds were now more accurate for my camera, and that I was getting
>a 10 stop range out of both emulsions.
>
>I have never run these tests on color negative stock, so I can't vouch for
>their performance. I know that I went through a lot of grief trying to come
>up with a black and white negative film combination that worked for me to
>get a 10 stop range (TRI-X at EI 250 in HC-110 and ELITE paper). Out of the
>box standards for both KODAK and ILFORD gave me film that was underexposed,
>and with a 9 stop range.
>
>My point is that you need to test the films that you use to determine what
>the reponse curve is for your camera and your color lab. Once you know
>that, you can make great technical images (creative images is another
>matter).
>
>I personally, tend to shoot transparency stock. It make it easier for me to
>organize things. Transparencies are denser than negatives, so I would
>expect that to make them grainier, but that has not been proven to me. Film
>is so much faster and finer grained today than 20 years ago.
>
> I have not reviewed any Zone System books in a long time. I always had a
>hard time with Ansel Adams writing, Minor White was a lot easier to read.
>It is not just a technique for working with B&W negative technology
>(although that does give you the most control). It is applicable to colog
>negative, color transparency, B&W transparency, and digital cameras too.
>
>----- Original Message -----
>From: "Bernie Kubiak" <bkubiak@mediaone.net>
>To: <filmscanners@halftone.co.uk>
>Sent: Thursday, November 22, 2001 9:12 AM
>Subject: Re: filmscanners: Negs vs slides again: was Color Negative Film
>Poll
>
>
> > Being new to the group, I've missed previous discussions. Thanks for the
> > info and broadening my perspective (by about 6 stops)!
> >
> > ----- Original Message -----
> > From: "Julian Robinson" <jrobinso@pcug.org.au>
> > To: <filmscanners@halftone.co.uk>
> > Sent: Thursday, November 22, 2001 12:35 AM
> > Subject: filmscanners: Negs vs slides again: was Color Negative Film Poll
> >
> >
> > >
> > > >The bigger question is why shoot print
> > > >film if you're going to scan the images?
> > >
> > > This has been covered before, but I just decided to check my facts by
> > > looking at the characteristic curves for representative Kodak films.
> > These
> > > curves demonstrate admirably the main reason you might choose to shoot
> > with
> > > negative film over slide... simply, you can capture a LOT more of the
> > scene
> > > brightness range with neg film.
> > >
> > > - Slide films capture a range about 5 stops max.
> > > - Neg films capture a range about 11 stops!!
> > >
> > > You can't print this whole range of 11 stops directly, but one of the
> > great
> > > advantages of scanning is that you can process the image to restore as
> > much
> > > of this range as you want if you are prepared to do a bit of work. I do
> > > this regularly to improve reproduction of my high-contrast scenes. It
>is
> > > precisely BECAUSE I am scanning my images that I choose negs.
> > >
> > > At least if you have the info on film, you can access it somehow, if
>not,
> > > (as in slides) it is gone forever.
> > >
> > > I agree though that a well-exposed flatly lit scene on slide is a
> > beautiful
> > > and satisfying thing, but most of real life is not flatly lit, certainly
> > > not limited to 4 or 5 stops range. And I agree that grain is more of a
> > > problem with negs than slides, especially when underexposed when it can
>be
> > > completely unacceptable.
> > >
> > > These other advantages of the slide probably make it the best choice in
> > > studio work where you have complete control over lighting, but for
>travel
> > > and other more spontaneous work, this amateur anyway would choose neg
> > films
> > > every time.
> > >
> > > Julian
> > >
> > >
> > >
> > > At 23:05 21/11/01, Bernie wrote:
> > > >The bigger question is why shoot print
> > > >film if you're going to scan the images? I shoot chromes for most of
>my
> > > >color work. You have an original image for reference, can use
> > Ilfochrome,
> > > >reversal or an inteneg, if you want to print conventionally and
>scanning
> > is
> > > >more straightforward with a slide. Provia 100 and 400 are my
>favorites.
> > >
> >
