Is exposure index and ISO actually relevant

[redbandit]

in the realm of photographic work anymore?

Sure, you can choose to expose a film at box speed, or at your own preferend iso for the light meter to play with. You just have to learn how to develop it right...

Problem that pops up, is that with film, change the developer, change the agitation pattern, change the time you dump the developer out... You create things that change how the developed negative comes out to you.

SO if say using rodinal and foma 400, "barney" claims you can only get good shots using EI 320 setting and 1+50, but mike shoots box speed and uses 1+100, and so forth... why does one even CARE what the light meter or even the iso being shot at?

To further the point... I leave my nikon digital on auto ISO.... when i get bored i toss it to auto modes and take random exposures on things... I learned that using the EV scale i can change the shutter speed 2 or 3 times,,, and using the same aperture, i can drop the AE iso from 20,000 down to 800 with no trouble...

 

[koraks]

Of course it's relevant. In film photography, if you want to somewhat accurately control exposure, you still have to know what to set the meter to.

For people who don't care how the negatives turn out or who are unaware of the basics of metering technique, of course it doesn't matter.

 

[pentaxuser]

redbandit, if you don't care then it is irrelevant to you but that presumably applies to everything you, I or the rest of humanity does

pentaxuser

 

[xkaes]

It is basically irrelevant -- if you do your own tests -- but it gives you a place to start, no matter what film, developer, and paper you use. And once my tests are done, I know how to set my meter for each film.

But it is relevant -- and essential -- to those photographers (the VAST majority) who don't do their own tests.

 

[BradS]

Film speed is one of the four basic variables in exposure. It is not only relevant, it is absolutely critical.


wait...are you asking is the ISO film speed, printed on the box relevant? It is but some only take it as a hint, a starting point for exposure index. Others use it as exposure index. Either way, film speed is certainly relevant.

 

[grain elevator]

To further the point... I leave my nikon digital on auto ISO.... when i get bored i toss it to auto modes and take random exposures on things... I learned that using the EV scale i can change the shutter speed 2 or 3 times,,, and using the same aperture, i can drop the AE iso from 20,000 down to 800 with no trouble...

That you think this relates to film exposure suggests to me that you lack understanding of exposure/what ISO/EI is. Do some reading?

 

[Alan Edward Klein]

I think what he's saying is that you can vary the ISO setting on film a little (from box speed) and a whole lot on digital and the cameras will still be able to provide a shot that's exposed OK. We're not limited to some preset selection of ISO. I don't think he's saying the triangle of exposure can be ignored.

 

[Sirius Glass]

in the realm of photographic work anymore?

Sure, you can choose to expose a film at box speed, or at your own preferend iso for the light meter to play with. You just have to learn how to develop it right...

Problem that pops up, is that with film, change the developer, change the agitation pattern, change the time you dump the developer out... You create things that change how the developed negative comes out to you.

SO if say using rodinal and foma 400, "barney" claims you can only get good shots using EI 320 setting and 1+50, but mike shoots box speed and uses 1+100, and so forth... why does one even CARE what the light meter or even the iso being shot at?

To further the point... I leave my nikon digital on auto ISO.... when i get bored i toss it to auto modes and take random exposures on things... I learned that using the EV scale i can change the shutter speed 2 or 3 times,,, and using the same aperture, i can drop the AE iso from 20,000 down to 800 with no trouble...

Do not listen to barney or mike, they are so full of it their eye are brown and they know less than nothing. I am the only one anyone should listen to.

• Get the your cameras and light meters calibrated
• Put a protective filter on your lens
• Meter without the sky in the field of view or on the subject without the sky or use an incident meter
• Shoot box speed
• Adjusting for shadows with the Zone System or experience when necessary
• Adjust for filter compensations as necessary

 

[redbandit]

I think what he's saying is that you can vary the ISO setting on film a little (from box speed) and a whole lot on digital and the cameras will still be able to provide a shot that's exposed OK. We're not limited to some preset selection of ISO. I don't think he's saying the triangle of exposure can be ignored.

The triangle so to speak is still important, but with the advant of things... the only portions of the triangle that matter seem to be shutter speed and aperture.

Look at Foma 400 in 134.. box says 400, everybody else says it has to be shot at 320 or less to get reliable images.. Thing is,,, the film does make images at box speed, and depending on the actual PROCESSING done... developer, length of development, agitation pattern when developing it... the results completely negate the actual "specified" EI everyone uses..

Even with other films.. the classic "develop the film 20 percent longer if you were shooting in bright light.." makes a preset ISO / EI as irrelevant.

 

[BradS]

Speed + Light = Aperture + Time

Just because you let the computer choose one or two or, in the case of digital, all three of the free variables doesn't make any of them irrelevant.

 

[wiltw]

Exposure Index is still relevant. How I used it 30 years ago when shooting weddings...I took ISO 160 color negative film, used Exposure Index 100 to expose it, then sent it to a commercial lab for standard processing. By increasing exposure +0.66EV, I was more sure that the shadow areas did not come out 'muddy' looking in the shot; the well-lit areas could easily deal with the added exposure with zero visible affect on the photo quality. Those principles are still valid today, too.

In thge digital world, one might say that the practice of ETTR (Expose to the Right of the histogram) is merely utilizing an Exposure Index higher than the factory calibrated ISO, to move the sensor response toward the right side of the histogram.

 

[bluechromis]

I am not quite sure what the OP is saying, but I will respond to this part:

"SO if say using rodinal and foma 400, "barney" claims you can only get good shots using EI 320 setting and 1+50, but mike shoots box speed and uses 1+100, and so forth... why does one even CARE what the light meter or even the iso being shot at?"

I don't see how if people shoot at different EI's why they would have less need to meter to get the proper exposure. The comparison to auto ISO mode with digital doesn't fit with analog. The camera lacks the ability to change the characteristics of the film automatically. The photographer must manually make adjustments for different ISO's with processing time etc. But even then there is little photographers can do to change the inherent sensitivity of a film. One can compensate for underexposure with increased development, but the film is still underexposed. You used to hear that you could shoot a roll of film with all different ISO's and throw it in a two-bath developer, and it would come out fine. But that's an exaggeration.

 

[grain elevator]

I am not quite sure what the OP is saying, but I will respond to this part:

"SO if say using rodinal and foma 400, "barney" claims you can only get good shots using EI 320 setting and 1+50, but mike shoots box speed and uses 1+100, and so forth... why does one even CARE what the light meter or even the iso being shot at?"

I don't see how if people shoot at different EI's why they would have less need to meter to get the proper exposure.

But this raises the question of why people shoot the same film at different EI's. I often see where a beginner will ask what the best EI to use with film and developer like Tri-X and D-76 is. People will offer suggestions, and off the beginner will go shooting at the speed recommended.

I have mixed feelings about this. People need to start somewhere, and it is not bad to give a suggestion that may generally give satisfactory results. But it troubles me if the beginner goes off and shoots with that EI exclusively without ever knowing why. Sometimes people will glue down some camera adjustments, like the X flash setting on my Mamiya C330 lenses, so it won't get set wrong. If someone just blindly uses an EI it is like they have glued down one dimension of the exposure triangle.

There are some objectively measured characteristics of film, like its curve and speed point. But ultimately, the choice of EI is a subjective decision based on what the photographer is trying to achieve. More than other parameters like aperture and shutter speed, beginners are apt to get the impression that there is just one EI that is best for everything that can be scientifically determined. I am not accusing anyone on Photrio of saying such a thing, but beginners sometimes get that impression, partly because manufacturers print the film's box speed in big letters on the package and it seems one should follow the maker's guidance. But we can see how in the case of Delta 3200 and Tmax P3200, if they don't read the fine print that says what the films' ISO's really are, doing what is printed on the box may not be ideal.

You don't want to overwhelm newbies initially, But I agree that it is best if they eventually do some testing so they begin to understand the effects of changes in exposure and development to be able to optimize parameters for the work they do. The question is how to get them from point A to point B. Maybe direct them to some good reading materials or tutorials.

I feel the opposite is the case - many film beginners and youtubers these days seem to treat EI as another variable along with shutter speed and aperture, which it isn't, or at least seem to vastly overestimate the usefulness of varying it. Maybe that's a misunderstanding coming from digital cameras, people see they can adjust ISO on a film camera as well and think it does the same thing... maybe also the OP's misunderstanding. Of course EI can be varied if light dictates or tweaked a bit to suit other process variables, but sensitivity is baked into the emulsion and straying very far from the ideal exposure (especially towards underexposure, leeway for everexposure is often significant but nothing is gained by giving more exposure beyond a point) will only yield special effects negatives.

 

[Steven Lee]

The way I read the OP's question is that exposure index is useless when conveying information about exposure because by itself it's not universal. It depends on one's metering and development. In practice this means that if I take someone's advice of exposing HP5+ at 250 and "copy&paste" it into my workflow, I may end up with a result very different from the person's giving advice.

If that's the case I agree wholeheartedly. I always ignore EI comments for this reason.

 

[grain elevator]

The way I read the OP's question is that exposure index is useless when conveying information about exposure because by itself it's not universal. It depends on one's metering and development. In practice this means that if I take someone's advice of exposing HP5+ at 250 and "copy&paste" it into my workflow, I may end up with a result very different from the person's giving advice.

If that's the case I agree wholeheartedly. I always ignore EI comments for this reason.

I don't read this in the OP at all but if that is indeed meant, I also agree.

 

[pentaxuser]

Maybe redbandit will help us by saying which of our posts with their respective explanations get closest to what he meant, otherwise we end up discussing what we think he meant

pentaxuser

 

[xkaes]

This is what was said, and it's absolutely correct:

"you can choose to expose a film at box speed, or at your own preferend iso for the light meter to play with. You just have to learn how to develop it right..."

 

[FotoD]

ISO/EI is perhaps irrelevant. What matters is how many photons hit the film. Each film has a minimum number to start building density.

But it's usually easier to work with ISO/EI than counting photons.

 

[xkaes]

What matters is how many photons hit the film.

And how much developer hits the photons.

 

[FotoD]

Hold on, I'm supposed to pour developer on the photons?

 

[bluechromis]

The way I read the OP's question is that exposure index is useless when conveying information about exposure because by itself it's not universal. It depends on one's metering and development. In practice this means that if I take someone's advice of exposing HP5+ at 250 and "copy&paste" it into my workflow, I may end up with a result very different from the person's giving advice.

If that's the case I agree wholeheartedly. I always ignore EI comments for this reason.

Okay, I was confused about how the digital autoexposure thing relates to this.

 

[Andrew O'Neill]

Of course they are relevant. Go stick a roll of Pan F in your camera and set the ISO to some random number, and see what you end up with... Hey, you might get lucky!

 

[ic-racer]

With B&W negative, the easy rule of thumb is "the more you enlarge, the less latitude"
Contact prints from B&W negatives have the greatest latitude, but mostly for over-exposure.

 

[Pieter12]

Have fun. I hope you like your photos.

 

[Saganich]

Regarding b&w film, the iso works to help manage information in zones 1-3, whereas the other variables mentioned are generally used to mange Zones 7-9. For example I'm working with Kodak double X trying to get a routine ISO and development time. It's rated at 200, but I'll shoot it 400 and get almost no information in Zone 1 and 2. The point is that's not going to change with development time, agitation, or the usual chemistry...I'll get the same density down there at 4 min or 10 min dev time in standard solvent developer like D76. So, if I want more information in zone 1 and 2 I'll have to rate the film at 200 or less. It depends on what you want, higher contrast look with less tonal values, or less contrast look with expanded tonal values. Auto exposure is kinda the foil of this, metering everything to middle grey. When I first started taking pictures I had a manual Nikon and then was gifted a 'fancy' minolta with auto everything. It took me 10 years to recover for the horrors of auto exposure in B&W.