Understanding EI???

Ray Rogers · Jan 19, 2010

CPorter said:
Come on Ray, if you didn't mean to imply it, then ok that's cool, then what does your statement below mean then?

"The whole sensitometric/zone system thing sort of falls down when one considers that with all the previsualizaton and zone placement going on, dodgeing and burning in still has to be resorted too..."

.....still has to be resorted too..............Sounds to me you think that if one uses dodging and burning during printing, after having gone through the process of visualization, exposing, and developing the negative, then the ZS sort of "falls down", presumably on its face, because it did not yield a flawless negative.

No attitude here, just trying to figure out what your talking about.

Chuck

Thanks Chuck for the no attitude attitude So much unnecessary stress is created by poor communication and subsequent defensive over reactions.

We often take for granted that communication is easy but perhaps it is mostly luck and faith that get us through many exchanges. We think we are good at language but the whole concept of effective communication skills sort of falls down when one considers that with all the thought and careful choice of words going on, we may still have to rephrase ourselves several times before we are understood.

I guess what I am trying to say is not that the zone system concept, nor the concept of effective communication skills themselves are flawed but rather that they both provide an illusion of great prowess, and that those illusions do not stand up to close scrutinity. The illusion sort of falls down. There is a difference between the thing and the illusion it creates and that is the reason for my choice of the words "thing" and "sort of". I guess you could even say that we are saying the same thing... sort of.

RalphLambrecht · Jan 19, 2010

Ray Rogers said:
Ralph, I don't understand why you think it is normal for your reply to preceed my statement. :confused:
Perhaps on your computer screen, post #220 is made by me and #228 is made by you? It is the other way around here.

On my screen, post 220 is your response to my post 228, and that is a glitch IMO.

I sense no good will come of pursuing (pursueing?) this so I will stop here so we can maintain the quality of this thread.

Ray

I see what you mean now, but I have no idea how this happened.

DLawson · Jan 19, 2010

Ray Rogers said:
Ralph, I don't understand why you think it is normal for your reply to preceed my statement. :confused:
Perhaps on your computer screen, post #220 is made by me and #228 is made by you? It is the other way around here.

On my screen, post 220 is your response to my post 228, and that is a glitch IMO.

Nope. #220 is Ralph's response to you posting in #218.
#228 is you, for some reason (I assumed trying to clarify what you had said) reposting similar text as #218 (though 228 doesn't have the "rib at ZS" part).

RalphLambrecht · Jan 19, 2010

DLawson said:
Nope. #220 is Ralph's response to you posting in #218.
#228 is you, for some reason (I assumed trying to clarify what you had said) reposting similar text as #218 (though 228 doesn't have the "rib at ZS" part).

That kills my theory! I thought, this was proof that I'm faster than the speed of light. You'd burst my bubble.

Ray Rogers · Jan 19, 2010

DLawson said:
Nope. #220 is Ralph's response to you posting in #218.
#228 is you, for some reason (I assumed trying to clarify what you had said) reposting similar text as #218 (though 228 doesn't have the "rib at ZS" part).

I think you are correct...

I can no longer find any logical reason to think Ralph is faster than the speed of light.
Sorry Ralph.

Thanks DLawson.

Stephen Benskin · Jan 19, 2010

RalphLambrecht said:
Steve

The combination of Zone System and dodging & burning gets me pretty close to the original visualization of the print. I use the Zone System to set shadow and highlight points, and then use a variety of print manipulations to alter the other tonal values. This way, I can control the entire print and create the emphasis I like and where I like it. To me, the Zone System is not one path of many, it is one tool in a set of many. I use it together with others (including hybrid printing) to get the print I want it. It's not an either/or choice to me. I like to make use of all reasonable tools. Others may have a different approach, and that's great.

Thanks Ralph, I'll be more careful with my metaphors in the future.

Chuck_P · Jan 19, 2010

stradibarrius said:
As I look through the Gallery and see the the film used and the ISO rating I see that many time people shot film at rating different than the box speed.
Can some one explain the basic reasons that this technique is used?

UUHHHHHHH......., well, hmmmmm........, you see it's all about........no, wait a sec......sometimes it makes........it can be beneficial to...... Oh crap!

That's just the way some of us do it, OK! Come on, what do you want from me?!!

Ah, I've enjoyed this thread.

sanking · Jan 19, 2010

CPorter said:
UUHHHHHHH......., well, hmmmmm........, you see it's all about........no, wait a sec......sometimes it makes........it can be beneficial to...... Oh crap!

That's just the way some of us do it, OK! Come on, what do you want from me?!!

Ah, I've enjoyed this thread.

Ian Grant said it all back in message #2.

"We usually down rate for greater tonality and improved shadow detail, but many of us have run tests to determine the effective EI of a film/developer combination with our equipment & processing technique to give the contrast/tonality we require in a print at a set mid contrast paper grade under certain lighting conditions."

The rest of us were just pissing into the wind.

Sandy King

Poisson Du Jour · Jan 19, 2010

To put things in brutal perspective, Arts degrees with majors in photography do not mention EI anywhere; it is certainly not relevant to earning a living as a photographer! So what are the folks here doing belting it with Biblical fervor and sounding like sons of Proust? As stated way back in this thread all it serves to do is a notational reference to a non-standard film rating. Big deal. The rest is just a load of monumental techspeak. Move along, move along.

Photo Engineer · Jan 19, 2010

Ray Rogers said:
I can no longer find any logical reason to think Ralph is faster than the speed of light.

Ray, logic breaks down at the speed of light.

PE

Ian David · Jan 19, 2010

Poisson Du Jour said:
To put things in brutal perspective, Arts degrees with majors in photography do not mention EI anywhere; it is certainly not relevant to earning a living as a photographer!

I don't think that an Arts degree with a major in photography is necessarily relevant to earning a living as a photographer either, is it?

Ray Rogers · Jan 19, 2010

Photo Engineer said:
Ray, logic breaks down at the speed of light.

PE

Poisson Du Jour · Jan 19, 2010

iandavid said:
I don't think that an Arts degree with a major in photography is necessarily relevant to earning a living as a photographer either, is it?

If you actively work as a photographer, planning, producing, selling and referring-on work to other photographers, it certainly has relevance and kudos to boot. And the business side of earning a living and getting ahead of those around you is a definite positive.

Photo Engineer · Jan 19, 2010

sanking said:
The rest of us were just pissing into the wind.

Sandy King

Thanks Sandy. I feel relieved. If you get what I mean.

PE

Photo Engineer · Jan 19, 2010

iandavid said:
I don't think that an Arts degree with a major in photography is necessarily relevant to earning a living as a photographer either, is it?

I earned my living as a photographer for quite a few years and have a couple of degrees in chemistry. Oh, and a minor in math. Do they count?

PE

2F/2F · Jan 19, 2010

Just checking back in.....Have you guys figured out what my EI is yet?

Poisson Du Jour · Jan 19, 2010

Photo Engineer said:
I earned my living as a photographer for quite a few years and have a couple of degrees in chemistry. Oh, and a minor in math. Do they count?

PE

They certainly would, PE!
I can perhaps identify with chemistry qualifications given that a long-time cycling friend is a chemical engineer working in polyolefins with LyondellBasell. Not a bad job with lots of international travel, especially considering he gets 3x as much as I do! He's happy. I'm happy. Sorted.

Ray Rogers · Jan 20, 2010

Stairway to Perfection...

2F/2F said:
Have you guys figured out what my EI is yet?

EI is a very personal, very private figure.
Imagineer- and that you must discover, despite your fear!

With your shadow detail hidden in your soul
There glides a lady called ISO
Who shines white light henceforth to show
How every image she'll turn to gold

And should you meditate "2F/2F = 1"
Windowpanes will listen very hard to know
The Truth will come as shutter falls
When all are one and one is all
Use EI and not ISO....

Kirk Keyes · Jan 20, 2010

Ray - now in haiku form, please.

Sirius Glass · Jan 20, 2010

sanking said:
The rest of us were just pissing into the wind.

Some of us are just passing wind.

Ray Rogers · Jan 21, 2010

"... of the Beholder"

Kirk Keyes said:
Ray - now in haiku form, please.

Sorry Kirk,
I must have passed out.
(Did someone fart?!)

Obviously, Haiku also isn't my "Forte"

I... S... O... Yes? No?
Film, Camera, Lens Data -Why?
Art's in the E... I... !

Hope you are not too dissapointed, Kirk.

Ray

2F/2F · Jan 21, 2010

Ray Rogers said:
And should you meditate "2F/2F = 1"

Ah...but the slash in 2F/2F is not a division symbol! In fact, with 2F/2F, there are 4F total.

ISO speed is what the film is with ISO testing. Simple.

EI is what you need to call the film to get the exposure you want.

All you are doing when using an EI that does not match the ISO speed is applying exposure compensation. Simple.

Another way to look at it is that all you are doing is using the index number that lets you consistently get the exposures you want to get. Simple.

We don't all want to get the same exposures. We don't all judge exposure the same way either. Hence, we will all input different EIs into our meters in order to get what we want. Simple.

As for why you can't get the exposure you want using the ISO film speed as the EI, few people will ever bother to figure this out, hence the use of EIs as compensators for WHATEVER the difference is. As long as your exposures are consistently different than what they should be using the ISO as the EI, you can compensate for the difference by using an EI other than one that matches the ISO film speed. Simple.

So why all the fuss? ISO methods are simply one way to measure film speed. If the ISO film speed does not give you what you want for the way you do things when you use it as your index number, then use a different index number.

...but to say that the ISO speeds are "not correct" is not true. The ISO defines their own parameters, therefore, by definition "ISO film speeds" are all correct, in ISO parameters. If the ISO's parameters do not work for you, use other ones. Simple.

Ray Rogers · Jan 21, 2010

Stradibarrius... Did you get that?

eddym · Jan 22, 2010

It's really very simple, Grasshopper; there is no correct answer. There is only the Search.

Stephen Benskin · Jan 23, 2010

I found a couple of nice excerpts from Jack Holm, Exposure-Speed Relations and Tone Reproduction, IS&Ts 47th Annual Conference, 1994, on film speed and exposure that some might find interesting.

“Film speed exposure determination standards are based on the correlation of two experimental values, the film speed and the average scene luminance. These standards describe a speed point exposure which is deemed to produce a density of densities of significance for a particular film type. The optimal ratio between this exposure is then determined and used in the calculation of a constant for the speed equation. Film speeds are obtained for specific films by determining the speed point exposure and plugging the value into the speed equation to get the film speed. Since this film speed was determined assuming a particular speed-point-exposure/mean-exposure ratio with the minimum variation in image quality.”

“The speed values obtained from these exposure values should place the exposure values so that the corresponding tones of the scene are optimally reproduced.”

“It is important to note, however, that mononumeric speed values provide information about the predicted output at only one point on the characteristic curve. If a speed value is based on a shadow density, it will predict only the exposure required to produce that density, and similarly for highlight and other speed point exposure criteria. Also, typical light meters can only read one luminance value for a scene and thereby predict only one film plane exposure. The actual tone reproduction is therefore dependent on: the speed point exposure, the desired reproduction of the speed point exposure, the metered exposure, the desired reproduction of the metered exposure, and the difference between the speed point and metered exposures.”

Understanding EI???

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