"Real" ISO values of sheet film.

Bill Burk

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BetterSense said:
I still don't understand why it's important to even know your film speed.
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Hi BetterSense,

For me it's a journey towards an aim.

I want to aim in the middle of a target confidently, so that when things go wrong (and they will), the tolerance is all around me.

I don't want to be aiming for the edge condition where the slightest miscalculation leads to a difficult to print negative or a lost shot.

I'd also like to know the where the edges are in case I am forced into a situation where I need the minimum exposure, like handholding in near-darkness.
 

BetterSense

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I want to aim in the middle of a target confidently, so that when things go wrong (and they will), the tolerance is all around me.
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I find that negative film has lots of tolerance.
I don't want to be aiming for the edge condition where the slightest miscalculation leads to a difficult to print negative or a lost shot.
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I don't find a slight miscalculation leads to a difficult to print negative. It find that it takes a substantial miscalculation to lead to a difficult to print negative.
I'd also like to know the where the edges are in case I am forced into a situation where I need the minimum exposure, like handholding in near-darkness.
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In situations like that, I already know one thing about my film speed...it's not fast enough. I already know I will be underexposing the film so I simply expose as much as I can. Knowing more about the speed of the film doesn't actually change anything.
 

ic-racer

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BetterSense said:
\ Knowing more about the speed of the film doesn't actually change anything.
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Nothing wrong with your methods as stated in your various posts, but, unless you only shoot one film how do you keep exposure straight? If you call one film "green box" and another "yellow box" then these are your film speeds.

Film speed can be a number or a word or a mindset, either way its just a question of semantics.

Obviously one can choose to ignore film speed and shoot with random exposures, but it does not sound like you are doing that.
 

Bill Burk

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Hi BetterSense,

I just saw that you don't use lightmeters. Say no more. I get that you don't need to do testing for speed.
 
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markbarendt

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I have come to the point where I agree that film testing of relatively fresh, well cared for film, that is processed per the manufacturers instructions, is a WOMBAT.

I proved this for myself when I came back to film and developing a few years ago.

I read the instructions, I shot at box speed, I developed normally, and (to my surprise) I got good usable results. This has proved true for B&W, E-6, and C-41.

Where testing does seem to have real value, is when a non-(ISO)-standard result is needed or expected or being designed or where I lack understanding.

I got ticked off a while back at HP5 and did some testing. I learned more about me than I did about the film. HP5's "speed" matched the instructions, as did Delta's, as did TXP.

Through normal shooting I have actually learned more about getting good prints and developed more understanding with regard to the exposure settings I choose.

These are generally simple things that are obvious without formal "speed testing" like; that underexposure/thin negatives suck and that there is normally plenty of headroom for highlights with negative film.

Some are a bit more complex like; that a color film exposure is actually three exposures and that under exposure of even one of these sucks. This is tough to meter for, or even test for though, given the variations in light sources possible.

Experience "shooting normally", generally gives me plenty of feedback about what I might try next time.
 
OP
OP

andysig

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Fred Newman: thanks for the link to BTZS. That's a very interesting site although there's no way I intend to get a fiddle player to accompany me in the dark room!

And thanks for all the other replies. Before I (very recently) started developing sheet film I knew about making compensations in exposure for extreme conditions e.g. open up a stop or two for snow-dominated scenes or for where detail in shadow is required. I did not know about subsequent adjustments in the dark room. I think I shall experiment a bit by shooting a few scenes twice: once as I have done in the past and a second shot halving the box ISO followed by compensatory development as per Steve's approximations. It will be interesting to see how the prints turn out (once I've got my darkroom set up).
 

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ic-racer said:
Obviously one can choose to ignore film speed and shoot with random exposures, but it does not sound like you are doing that.
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hi ic-racer ... i do that ...

i have a graflex slr ... and use it for 4x5 and 120 roll film ( i tape a graphic 23 back to it ) ...
i use a variety of films ( asa 25, 125, 100, 400, 160 &C )
and never change my exposure. it all gets exposed wide open which varies depending on my lens from 3.8 to around f5.6 or 6ish, and 1/15thS which also varies
depending on how cold it is, and finicky my shutter is, sometimes it is longer,
sometimes it is shorter than that ...
i process everything i shoot in the same developer, for the same length of time
all at once ( color and black and white ) and it all comes out just fine ...

i have a lot of respect for people who are in complete control of every aspect of their
photography ( zone and beyond zone ... ) from exposure to processing ..
but often times this just isn't necessary.
 

Q.G.

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One question: why?

No. Make that two: what is your definition of fine?

jnanian said:
i have a lot of respect for people who are in complete control of every aspect of their
photography ( zone and beyond zone ... ) from exposure to processing ..
but often times this just isn't necessary.
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You mean those times that you luck out, and get something that's still usable?


You make it sound as if it is difficult and a lot of hard work to take the guessing and luck out of the process. It's not. It's extremely easy.
And it 'pays', in that - though you think it all comes out fine anyway - you will learn that there is "fine" and there is "fine".
 

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fine to me means just that ... fine
i have no trouble scanning or enlarging or contact printing my negatives
portraits, architecture, landscapes &C ...
and people i have sold things to haven't complained either ...
i get kind of tired with perfect-pretty pictures, so if that is what
YOU mean by "fine" well, i guess my images aren't fine

film has a lot more latitude/leeway than most people realize ( or want to admit ).
people, especially on photography forums, like to make issues out of things that aren't really that important.
if using a meter is important to you, than do your thing.
"perfect exposures" really aren't that important to me.
there is no such thing as perfection anyways, and no magic bullet to get it.

none of this matters, does it ?
 
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markbarendt

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Q.G. said:
One question: why?
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Can't answer for jnanian, but I have to say that in many cases I ignore my meter, because of the tool I'm using at that moment.

My Holga, my no-shutter petzval on my Calumet, and the 1/400th minimum time on my RB all tend to force me into places where I have no choice except to deal with whatever I happen to get because of the the "artistic choice" I made in picking that tool.

Q.G. said:
No. Make that two: what is your definition of fine?
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This is an exceptional question. We all need to answer it.

We do need to understand though that the "important part" of the SBR is something that we each get to define and where we choose to do our work.

Assuming negative film is in use, as long as we get the important parts of the SBR to land on a usable part of the film curve we can create prints that are "just fine thank you" with our enlargers. (Trannies are admittedly a different case.)

If we/you/I/the client wants to add requirements; like being able to print easily at a consistent grade, aperture, and time; then sure, more accurate camera exposure is required.


I agree that it is not terribly hard to be more accurate "in camera" but that isn't always where I want to do that work.

There is a real trade-off here; complicate my shooting or complicate my printing.

Many negative films have so much extra straight line on their curves that 3-5 stops over "normal", doesn't hurt a thing; it just means that some work has been shifted to the darkroom.

Take for example, disposable cameras; the 800 speed C-41 film does a very respectable job from sunup to sundown; even on a beach or a ski slope, some work is simply shifted to the printing process where exposure has to be adjusted for each frame.

It is work to decide on exposure for each shot, it takes time and brain "bandwidth" to make those decisions.

There are many times where I'd rather get my camera exposure "in the right range" and then use my brain's "bandwidth" to talk with or direct my subject, or to get a better composition, or be more selective in focus, or work to find the best perspective; things that can't be fixed later. I do this to get better content, knowing full well that I'll have to work harder to print that frame in a "fine" manner.
 

Stephen Benskin

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Q.G.,

It is pointless attempting discourse with someone who resorts to a pragmatic argument, “all I know is it works for me.” Kodak used to have a slogan, “You push the button, we do the rest.” They had a lot of very smart people who understood the process so you didn’t have to. Most consumer products are like that. I don’t need to know quantum theory to watch television or use a cell phone and there’s nothing wrong with not wanting to know. I don’t spend my time hanging out in electrical engineering forums.

But this is a technical photography forum. People come here to share and learn about the photographic process. The real question is: if someone isn’t interested in learning, why be here?
 

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Stephen Benskin said:
But this is a technical photography forum. People come here to share and learn about the photographic process. The real question is: if someone isn’t interested in learning, why be here?
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Are you saying that the only reason to post on APUG is to discuss technical matters? Are you also saying that technical matters exist in a bubble, free from trespass by conceptual/artistic discussion?
 

markbarendt

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Stephen Benskin said:
But this is a technical photography forum. People come here to share and learn about the photographic process. The real question is: if someone isn’t interested in learning, why be here?
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Wow, that's quite a statement.

:confused:
 

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it is pointless to engage in any sort of conversation with people
who are close minded and insist their way is the only way ...
 
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Sirius Glass

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I would add that it helps to know how to use a light meter. If you always include a large portion of the sky, you exposures will be off, regardless of whether or not you test film.

Back to markbarndt's statement:
You used the scientific method to come to the same place I did.
​
I use the ISO number to put the 18% Grey, or what I want to be 18% Gray in the mid-range of the exposure. I will take the average reading, highlight reading and the shadow reading and calculate the best exposure to get that SBR in the latitude of the film based on the ISO as a starting place. If one reads Ansel Adams et al about the Zone System and Beyond the Zone System, one can get all those desired results without doing the testing.

Of course if you insist on leaving the lens cap on, all the testing in the world will not help you.

Now if someone can tell my why the cell phone is melting my brain ... [A reference to a really mindless thread thesis, My Bad!]

Steve
 

MattKing

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2F/2F said:
Are you saying that the only reason to post on APUG is to discuss technical matters? Are you also saying that technical matters exist in a bubble, free from trespass by conceptual/artistic discussion?
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I took Stephen to mean that this forum ("B&W: Film, Paper, Chemistry") is a technological forum, not that APUG as a whole is solely a technological forum.

I would disagree with him a bit about that - I think this forum is intended to cover nuch that isn't technological - but I would agree that this thread is a technological thread, and do wonder why, for example, someone who rarely uses a meter would be concerned about "real" speed values for film.
 

Sirius Glass

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MattKing said:
... but I would agree that this thread is a technological thread, and do wonder why, for example, someone who rarely uses a meter would be concerned about "real" speed values for film.
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That would be a theological exposure argument rather than a technological argument.

Steve
 

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I don't use a meter perhaps half the time I shoot, and practically never with small format or digital. That doesn't mean I don't decide an exposure to use based on my best educated guess. I still want to know how fast my film is (though I find that box speed generally works just fine unless using the Zone System, which I do not do all that often now that I am shooting less sheet film than ever). Not using a meter does not mean that one does not want a decent exposure.
 

markbarendt

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Q.G. said:
As a question though, it is a really good one.
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No it is not, because it's assumptions are not defined well and it is not designed to be productive.

It actually it appears to be nothing more than a thinly veiled insult.
 

Stephen Benskin

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2F/2F said:
Are you saying that the only reason to post on APUG is to discuss technical matters? Are you also saying that technical matters exist in a bubble, free from trespass by conceptual/artistic discussion?
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You know I'm not saying that. Let's not be an absolutist. All ideas are important, but simply being a contraian is not a basis for a good discussion. Any statement, even a contrary one, should be supported with a decent supportive argument.
 

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John is not being a contrarian the way I see it. He is introducing a more free viewpoint and trying to blow a breath of fresh air on these technical matters. Ah! Refreshing! He is not telling anyone else what to do. Just explaining his way of having a spot of fun. I think he was also being FUNNY.

And I am one of the farthest people from being absolutist that most people meet! I have opinions and I state them, but I am not all about absolutes.
 
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Stephen Benskin

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Maybe I just read his intentions wrong. I'm just as willing to have a discussion about photographing without a exposure meter as anyone else if that was his intention. Edward and Brett Weston both rarely used meters. There's a great deal to discuss about the level of precision required to make a quality photograph.
 

Q.G.

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markbarendt said:
No it is not, because it's assumptions are not defined well and it is not designed to be productive.

It actually it appears to be nothing more than a thinly veiled insult.
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That's entirely what you make of it.

It has been aid by someone else already: it is highly peculiar that someone not interested in ISO values (a self-confessed disinterest) contributes to a thread like this one.
Where's the insult in that observation?

Unless (i.e. less peculiar) the person wanted to brag, tell us something like "only sissies need light meters and ISO values".
Mind you, that's all an assumption about the motives.
But if anywhere true, where would we find that insult would you say?
 
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