I'm confused about iso (Page 15): What you said was not clear to me. Only the ISO 100 option is at Sunny 16 (ISO 100 1/400s f/8). At the same exposure the ISO 400 film would be two...

selmslie Loc: Fernandina Beach, FL, USA

BebuLamar wrote:

I said change the film not change the ISO setting on the meter. IN fact forget about the meter.
Let take your favorite sunny 16 situation.
The scene is sunny 16
Aperture f/8, shutter speed 1/400,
Load the camera with ISO 100 film take the shot
Reload it with ISO 400 film take another shot
After developed the ISO 400 film will be a lot more dense but still both film received the same exposure.

What you said was not clear to me.

Only the ISO 100 option is at Sunny 16 (ISO 100 1/400s f/8).

At the same exposure the ISO 400 film would be two stops overexposed, assuming both got normal development.

It's unliely that both films would get the same development.

My normal development for different film/developer combinations at 75°F

srt101fan

Jack 13088 wrote:

If you don’t understand that the aforementioned triad are traded off to set what I think of as exposure perhaps you have a different term you would like to use? Of course, I doubt that the new exposure meter name would sell. At any rate I doubt exposure confuses anyone else.

I'm still looking for a definition of exposure.....

BebuLamar

selmslie wrote:

What you said was not clear to me.

Only the ISO 100 option is at Sunny 16 (ISO 100 1/400s f/8).

At the same exposure the ISO 400 film would be two stops overexposed, assuming both got normal development.

It's unliely that both films would get the same development.

That was what I said. Same exposure, different film, same development. The higher ISO film is overexposed but both film received the same exposure. The exposure didn't change only the results change when you change the film.

selmslie Loc: Fernandina Beach, FL, USA

srt101fan wrote:

I'm still looking for a definition of exposure.....

It's been defined many times here. It's a combination of aperture and shutter speed.

BebuLamar

selmslie wrote:

It's been defined many times here. It's a combination of aperture and shutter speed.

apeture, shutter speed and scene brightness determine exposure not film sensivity. Changing the film with different sensitivity (different ISO) will result in different densities on the film but doesn't change the exposure.

srt101fan

selmslie wrote:

It's been defined many times here. It's a combination of aperture and shutter speed.

I know the commonly accepted definition of exposure and I've already quoted it several times.

I want the folks who insist that ISO is part of exposure to give me their definition of "exposure ".

So far no takers....

selmslie Loc: Fernandina Beach, FL, USA

BebuLamar wrote:

apeture, shutter speed and scene brightness determine exposure not film sensivity. Changing the film with different sensitivity (different ISO) will result in different densities on the film but doesn't change the exposure.

Scene brightness is independent of exposure value (EV). You need the right ISO to match the film or digital image to the scene brightness (LV).

BebuLamar

selmslie wrote:

Scene brightness is independent of exposure value (EV). You need the right ISO to match the film or digital image to the scene brightness (LV).

So you couldn't understand either.
Same LV, Same EV then the exposure is the same although high ISO film would be more dense.
If you change the LV or the EV you change the exposure. If you change the ISO you do not change the exposure although the resulting image changes.
So yes you do need to consider the ISO to get the result you want but by definition ISO isn't part of the exposure.

selmslie Loc: Fernandina Beach, FL, USA

srt101fan wrote:

I know the commonly accepted definition of exposure and I've already quoted it several times.

I want the folks who insist that ISO is part of exposure to give me their definition of "exposure ".

So far no takers....

A lot of people are still confused. Is it your goal to humiliate them?

R.G. Loc: Scotland

Jack 13088 wrote:

You don’t know many engineers do you?....

That was my way of giving voice to the argument of the technically oriented among us. Whether it's some engineers or hardly any, you'll see that line of thinking in writings on this subject and also within this thread and others. Perhaps if I'd said "camera design engineers" or just "the technically oriented" it might have been a better fit.

But that line of thinking does exist, and if it came to guessing where it came from, my first guess would be the people who think primarily in terms of the technicalities of camera operation, and camera design engineers would be high on that list. I've no doubt there are lots of others - technicians, tech-heads etc.

selmslie Loc: Fernandina Beach, FL, USA

BebuLamar wrote:

So you couldn't understand either.
Same LV, Same EV then the exposure is the same although high ISO film would be more dense.

I understand the subject very clearly. If you use the wrong ISO you will get the wrong film density or digital image.

Look at the Exposure Triangle Calculator. It covers the entire subject.

selmslie Loc: Fernandina Beach, FL, USA

R.G. wrote:

That was my way of giving voice to the argument of the technically oriented among us. Whether it's some engineers or hardly any, you'll see that line of thinking in writings on this subject and also within this thread and others.

Some posters here understand the subject so clearly that they can write about it in depth.

Others just take pot shots and argue over semantics.

brentrh Loc: Deltona, FL

MCHUGH wrote:

If I am understanding you correctly you need to set exposure at the base ISO for the best image, only to change if you need lower or higher for the effect you want in the final image. Am I correct?

Yes

MCHUGH Loc: Jacksonville, Texas

CHG_CANON wrote:

'Need to' overstates how to be successful in digit... (show quote)

Thanks for the answer. I always like your responses to questions on UHH.

foathog Loc: Greensboro, NC

WDCash wrote:

Yeaaaa, Note I said the fog is clearing, not cleared.

I wouldn't worry about it. Film used to have 2 standards. American (ASA) and "European") ISO. You put the film in and you were stuck shooting within the range of its abilities. Although there were some films that you could "push". But if you pushed the whole roll would have to be processed accordingly.
Now you have the ability to put new "film" in on every shot. What could be nicer?? LOL