Agreed! Up to $40 seems worth it. Thanks so much Drew, and everyone! Learned a heckofalot and now have some homework to do
Agreed! Up to $40 seems worth it. Thanks so much Drew, and everyone! Learned a heckofalot and now have some homework to do
So I've been watching Ben Horne and Alan Brock's videos this morning while sipping my coffee. A thought occurred to me. Maybe I AM metering wrong. I recall reading in The Negative that lightmeters are calibrated to middle gray so that tends to be what I meter on. Sometimes I'll take the dark and light points, look at the range but also do an average and I'll usually set the shutter speed to that average.
That works - I get negatives, but I wonder if that's one reason why Pancro 400 seems slower. When I've shot it in 35mm I used on-camera metering for instance (though I recall those lightmeters, really any lightmeter, is tuned for middle-gray?).
Seems like I need to re-read that chapter. I'm having less issues with negative film but I've probably had more sheets of Velvia 50 exposed poorly than those exposed well (a few I felt I nailed though and I can understand why folks like Ben Horne pay so much money for 8x10 slide). I was conscious of the dynamic range but also still setting the shutter speed typically to the middle of the range, and I'm wondering if that's wrong (if I should be leaning on the highlights instead for slide and on the shadows for color negative).
That said, middle gray is meant to be Zone V? So as long as I'm within the dynamic range of the film I should, artistic license aside and expansion/contraction aside, have a well developed negative?
Sorry I know I'm kinda making things fly off the rails a bit with regards to the original question. And likewise it sounds like I need to do some (re)-reading as well
First, what is middle gray ? Middle gray can be different things, see here the "Table of middle grays":Originally Posted by m00dawg
https://en.wikipedia.org/wiki/Middle_gray
But, yes... you identify in the scene what you want it to be the middle gray in the print and this is Z-V, so what the meter says +/-0. You may want to modify that, but this is the "Standard" way.
If using the "true speed" of the film to meter, those areas that are not underdeexposed beyond 3.3 stops will be in the linear zone, so with no compression in the tonality but, depending on the film, as you underexpose you may be having a quality loss, so you need to know how (with your film/process) areas at -1, -2, -3 and -4 will be. You may place what you want in Z-V instead in Z-VII, to record the shadows that would be lost, in that case you may develop a shorter time to not have too high densities from overexposed areas, this underdevelopment won't mess much in the shadows. Basicly this is the N+/- development: expose for the shadows but develop for the highlights.
You may also want a safety factor, a modern LF shutter when was sold new it had a +/-30% specs accuracy, so a 1/30 can be 1/20 or 1/40, so it can vary a full stop and still being in specs. With negatives better to have a little overexposure than having a loss in the shadows, with slides (velvia) you have to ensure that you don't overexpose, because in that case highlights are easily damaged.
The method explained by Doremus is perfectly good, my recommendation is that first study well the BTZS book and later follow what Doremus explained, then you will be ready to nail what you want. There is a point since you don't see the meter reading, but you are visualizing the densities in the negative without thinking much, and the way the print will look straight, and what you'll have to do to print your visualization from your negative.
After you reach that mental point you will be in control with little effort and you will be able to focus on what light does with subject. Something like riding a bicycle, when one has practice he is not thinking in how he has to move le legs to pedal, and he may look forward and travel. And of course you'll also know when you should make accurate meterings for a complex scene.
The important thing is that when you have a pitfall you understand what happened, and what you would do instead next time.
There Pere! That does indeed help clear things up (and give me for to think about and do as I should probably get around to timing my shutters...).
Well, no...just because you know what Zone 5 is, doesn't mean the specific film involved will span the actual scene contrast, because neither is a fixed number. It all depends. And there is simply no substitute for accurately measuring your shadow versus highlight endpoints when significant contrast is involved. There are all kinds of potential exposure models you can choose from, including those already mentioned. But any of these have to be implemented hand in hand with a lot of actual shooting, developing, and printing before it really becomes easy. But don't worry. The learning process is fun and rewarding too.
On another site, another discussion, a fellow we call Photo Engineer said a film’s true speed is the point of inflection, the point at which instruments are capable of detecting the departure of the characteristic curve from base plus fog.
Bill, in fact this is the speed point, I guess, not the film speed.
But it's true that the film speed is calculated directly from the exposure in the speed point. (development also has to deliver the standard contrast to be the ISO speed.)
ISO standarizes the position of the speed point "m" as having 0.1D more density than unexposed areas (fog+base). The film speed instead is calculated from the exposure in the speed point to make an standard meter to aim x10 the exposure in the speed point, this is 3.3 stops.
Not sure that -3.3 stops works for reality. If I meter/place textured shadows (dark moss on underside of wet rock, shadowed underside of fallen tree) on zone 2-ish I get no texture. Zones 3-4 give better texture and shadow separation. I set the f-stop and shutter accordingly and keep my EI of 100 constant for FP4+. So in theory I should have a film speed closer to 50 for my processing style if I read all this stuff correctly. I guess I don't care what each zone's density is supposed to be, since i used multigrade paper which allows altering those relationships (somewhat). I focus on the high to low range and trying to fit it on the negative, and my final print may not represent the original scene's tonality.
The magic you are looking for is in the work you are avoiding.
http://www.searing.photography
By the way where you quote 3.3 you are rounding. It’s 3 and a third.
The 0.1 speed point also needs to meet the contrast parameters. My friend who sold me his sensitometer likes to point out why.
It’s because at the contrast parameters, the speed determined by Delta-X agrees with the speed at the 0.1 point
The speed in both cases now coincides with the outcome of Kodak’s first excellent print studies. That point is the 0.3 average gradient.
I like to point out that 0.1 is certainly easy to find and check. Even though the right place is 0.3 average gradient, it’s harder to mark that on a graph and two people might mark the same curves slightly differently leading to different readings.
So we get a quick reading of the speed by using the 0.1 speed point, and we stay connected with Kodak’s first excellent print studies at the same time.
It was a really good compromise when the 0.1 speed point was chosen... with the contrast parameters.
From "true speed" definition, a spot at -3.3 will have 0.1D over base + fog, so it will be in the "m" speed point. Pre 1960 ASA change it was -4.3
If that spot has not 0.1D (over base+fog) then it wasn't a "true speed" but an EI (Exposure Index).
...or we had a flawed metering/exposure/processing
The "Image Quality" we have in the "m" speed point is in the limit yet, grain may be different, etc... one has to know how -4,-3, and -2 looks with his film/process, of course.
But we also have sound inaccuracies in the process:
> A new Shutter had +/-30% specs !
> Is aperture scale exact ?
> Accurate bellows compensation ?
> Did we meter with a probe on the GG ? Have we flare from lens and a from a large circle illuminating compressed bellows ?
> Is film aged ? Is developer aged ? temp/time/agitation control ?
> Are shadows in LIRF because a moderately long exposure ?
If we are very accurate and using a true speed we have -3.3 in the "m". If we are not very accurate then we overexpose (negs) 1 or 1.5 stops and then we are in the safe side. We say "we rate" TMX at 50, but what we do is resurrecting the pre 1960 safety factor !!!!
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