If Zone V is density 0.7, aren't we throwing much of the dynamic range away?

jernejk · May 9, 2017

I've been re-reading through some theory and technicalities, and as far as I understand, metering and exposing for an 18% grey card (or using incident meter) will put that zone V at 0.7 density, assuming box speed and normal development time, right?

Now, looking at the data shets of tmax, trix and delta 400, that's roughly just about 2 or 3 stops from the toe. On the other hand, there are at lest 6 stops still available above zone V, which makes no sense for most subjects.

Using a spotmeter, one can of course measure for the shadows and put those in say zone IV (as actually suggested by Bruce Burnbaum on youtube), which would move Zone V to at least Zone VI.

But essentially it seems to me these modern films have so much dynamic range, one could (or should even!) shoot them at ISO 100 and simply measure the light with incident light meter/grey card, and for 80-90% of the scenes the negative will be just fine. On the other hand, shooting at box speed using that method will always lose some shadow details.

Am I correct or did I miss something?

Dali · May 9, 2017

Stop the theory and start the practice. Shoot the same scene with the same film by changing the ISO setting of the meter, develop the film and choose the best ISO for you.

MattKing · May 9, 2017

jernejk said:
On the other hand, there are at lest 6 stops still available above zone V, which makes no sense for most subjects.

Why doesn't it make sense?
Shadow detail is fine, but gradation in mid-tones and highlights is what makes the most difference when it comes to determining if a print is "successful".

Alan9940 · May 9, 2017

Not sure exactly where on the curve you're placing the "toe", but Zone 1 (exposure threshold of film) is 4 stops below Zone V. No idea where you got the idea that there are 6 stops available above Zone V, but Zone VIII (3 stops above) is about the last zone whereby some textural detail can be retained. Zones VIII and IX are right up there on the shoulder of the curve--that is, 3 - 4 stops above Zone V. Yes, highlight densities can be placed higher than Zone VIII, but then we're talking N- type development to bring those densities down into a printable range.

I totally agree with Matt that it's texture in the mid-tones leading to sparkling highlights that make a fine print. Anybody who has tested their film and knows their personal EI wouldn't have blocked up shadows, anyway, IMO.

zanxion72 · May 9, 2017

Every film has characteristics of its own. Zone V and the distinct zones above and bellow it will not look the same for all films. There are films that deliver higher contrast, others better midtones and others a long tonal range even with high contrast scenes (e.g. the wonderful and long gone Panatomic-X). Also, there are other factors that affect the result, developer, dilution, agitation, etc.
What you see in the charts is the graduation, or the tonal range if you like, you will get with these films. There are still six stops there, but with a higher effective density. Note that these curves vary with developer and temperature. You are offered with those for standard developers and standard development temperature.

Bill Burk · May 10, 2017

jernejk said:
... one could (or should even!) shoot them at ISO 100 and simply measure the light with incident light meter/grey card, and for 80-90% of the scenes the negative will be just fine. On the other hand, shooting at box speed using that method will always lose some shadow details.

Yes there is so much straight line that if you don't need speed, and don't demand highest resolution or minimum graininess... You can rate a 400 speed film at 100 and not give it any more thought.

You most certainly would improve your shadows, including the ability to dodge to bring in additional detail. You would also increase your darkroom printing time, and that can be a good thing.

But you don't have to go that far. I'm comfortable with 250 for a 400 speed film. And when I need the speed, I just dial in 400

jernejk · May 10, 2017

Since I don't have a density meter I'm trying to understand this from theoretical point of view first. What I'm missing is conversion of exposure index to lux-seconds applied on the film.

Let's say I'm photographing a grey card illuminated by the sun using an iso 100 film. The illumination is 81,900 lux. I'm using f16 at 1/100s. By how many lux-seconds am I actually exposing the film?

I'm quite sure there is a formula which translates illumination, reflection, f-stop and shutter to the actual film exposure in lux-seconds, but I could not find it.

Chan Tran · May 10, 2017

To answer your question.
Illuminance=81,900 lux
Aperture f/16
Shutter speed 1/100 sec.
Subject reflectance 18%

The illuminance at the film plane is 13.344 lux and so the exposure is 0.13344 lux.sec
Assuming the lens has a flare factor of 1.03, transmission factor of 0.90 and vignetting of 1.0. The lens is focused at infinity and the exposure is at center of the frame.
Check out these 2 link
http://www.largeformatphotography.info/articles/conrad-meter-cal.pdf
https://www.intl-lighttech.com/services/ilt-light-measurement-handbook

jernejk · May 10, 2017

Thank you Chan!
I found a formula on this site, although I get a bit different result:
Transmittance: 0.9
Reflectance (grey card): 0.18
Scene illumination: 81900 lux
f stop: 16
-> Illumination at film =5.2 lux
shutter:0.01s
-> exposure at film=0.052 lux
-> log exposure at film=-1.28

Which is actually quite close to the chart at the first link you provided (attached)! It's clear that using this kind of metering will result in very good separation of tones all the way up to zone XI, maybe even XII, while there is going to be very little separation in zones I-III.

David Allen · May 10, 2017

One thing that you have to factor in is that light meters are not calibrated to 18% grey but rather 12% grey.

Far easier than immersing yourself in theory and sensitometry is to do practical tests - takes a little bit of time, is boring but, once done, you will have calibrated everything to how you meter, how your camera works, how you develop and how you like to print.

The system that I teach can be found in this thread (look for my post #23):

(there was a url link here which no longer exists)

Bests,

David.
www.dsallen.de

Petraio Prime · May 10, 2017

jernejk said:
I've been re-reading through some theory and technicalities, and as far as I understand, metering and exposing for an 18% grey card (or using incident meter) will put that zone V at 0.7 density, assuming box speed and normal development time, right?

Now, looking at the data shets of tmax, trix and delta 400, that's roughly just about 2 or 3 stops from the toe. On the other hand, there are at lest 6 stops still available above zone V, which makes no sense for most subjects.

Using a spotmeter, one can of course measure for the shadows and put those in say zone IV (as actually suggested by Bruce Burnbaum on youtube), which would move Zone V to at least Zone VI.

But essentially it seems to me these modern films have so much dynamic range, one could (or should even!) shoot them at ISO 100 and simply measure the light with incident light meter/grey card, and for 80-90% of the scenes the negative will be just fine. On the other hand, shooting at box speed using that method will always lose some shadow details.

Am I correct or did I miss something?

You can capture only so much of the Subject Brightness Range (not 'Dynamic Range') in a negative. Ask those guys who photograph nuclear explosions.

http://www.npr.org/sections/pictureshow/2010/09/28/130183266/abomb

https://www.google.com/search?q=ato...+bomb+explosion+Edgerton&imgrc=Tb3-VT4xQ-fPPM:

Tones in the photograph should correspond to those in the scene 1:1 in the mid-tones; this cannot be achieved in the shadows and highlights. Reducing negative development to try to capture more tones results in flat-looking prints. In other words, the zone system is wrong.

Photo paper can reproduce only about five stops of density range:
http://www.filmscanner.info/en/Dichte.html

This means that you do indeed have to 'throw away' some of the range the negative is capable of holding. Reducing development to compress the 12 stops of a negative (a 'long-scale' negative) doesn't work: the print will look too flat. So, you have to pick your poison, so to speak. This truth is not acknowledged in the zone system.

lonelyboy · May 10, 2017

The limitation is your output media, not the negative. Negative film can capture about 12-13 stops but photo paper or computer monitor can only display about 7 stops, so it is about 3 stops above and below Zone V to have details.

Gerald C Koch · May 10, 2017

The Zone System attempts to match the tonal range of the subject to the tonal range of the printing paper. Since papers have a lesser tonal range than films it is the paper that is the limiting factor not the film. By manipulating the negative it is possible to make the most important parts of the subject appear to their best effect in the print.

I would suggest getting copies of Ansel Adams The Negative and The Print. They contain discussions along with examples of what AA was doing.

Leigh B · May 10, 2017

David Allen said:
One thing that you have to factor in is that light meters are not calibrated to 18% grey but rather 12% grey.

All the light meters I've calibrated for professional photographers over the years have been to 18% cards per the meter manufacturers' instructions. Never had a complaint of meters being off.

- Leigh

ic-racer · May 10, 2017

jernejk said:
metering and exposing for an 18% grey card (or using incident meter) will put that zone V at 0.7 density, ...

Am I correct or did I miss something?

You can place a card, on any zone. There is no 'standard.' The zone system is a creative tool (think Minor White).
If you are doing a film speed test, you need to make Zone I 0.10 when the film is processed to the appropriate gamma. That is a scientific test based on information gathered from a panel of observers.

Bill Burk · May 11, 2017

I think the exposure at the film plane is different than what's been offered so far.

I use this ruler strip to mark film speed on my graphs. Film speeds are where the curve crosses 0.10 speed point... and they correspond to a certain number of log meter candle seconds at that speed point.

100 speed film speed point receives -2.1 log meter candle seconds at the speed point.

I believe that exposure meters will try to put 10 times that much light on the film.

10 times -2.1 log mcs is -1.1 log mcs (across from the 10 speed point).

About 0.080 meter candle seconds at the metered point.

David Allen · May 11, 2017

Leigh B said:
All the light meters I've calibrated for professional photographers over the years have been to 18% cards per the meter manufacturers' instructions. Never had a complaint of meters being off.

- Leigh

Sorry, but the manufacturers work to an international set of standards and this is not 18%. The 18% grey card was developed by Kodak to represent a general average of all the tones in a general average scene. Even if meters were calibrated to 18% you then you have to accommodate for the fact that the Kodak grey card only gives 18% in a certain position with a certain reflectance that, in practice, is almost uncontrollable. That is why I advocate undertaking 'real world' tests that rely upon your way of metering, how your camera works (specific internal reflection and flare), how you develop, how you agitate and how you like to print.

Just do a one off test and then you have got it all sorted.

Bests,

David.
www.dsallen.de

Chan Tran · May 11, 2017

David Allen said:
Sorry, but the manufacturers work to an international set of standards and this is not 18%. The 18% grey card was developed by Kodak to represent a general average of all the tones in a general average scene. Even if meters were calibrated to 18% you then you have to accommodate for the fact that the Kodak grey card only gives 18% in a certain position with a certain reflectance that, in practice, is almost uncontrollable. That is why I advocate undertaking 'real world' tests that rely upon your way of metering, how your camera works (specific internal reflection and flare), how you develop, how you agitate and how you like to print.

Just do a one off test and then you have got it all sorted.

Bests,

David.
www.dsallen.de

My Minolta meters Flashmeter III, Spotmeter M, Flashmeter VI all agree with each others. All are calibrated to K=14, C=250 for flat diffuser and C=330 for the dome.
What does it mean when a reflected meter is calibrated to K14? It means that EV0@ISO100 is 0.14 Cd/m^2.
What does it mean when an incident meter is calibrated to a C=250? It means that EV0@ISO100 is 2.5 lux.
Now that if the light falling on a gray card is 2.5 lux and the card has a reflectance of 17.6% then the luminance of the card is 0.14 cd/m^2.

Leigh B · May 11, 2017

David Allen said:
Even if meters were calibrated to 18% you then you have to accommodate for the fact that the Kodak grey card only gives 18% in a certain position with a certain reflectance that, in practice, is almost uncontrollable.

Uncontrollable ? ? ?

Absolutely not.

You just have to know what you're doing.
I realize that's fallen out of favor in the 21st Century, but it's still valid.

- Leigh

David Allen · May 12, 2017

Leigh B said:
Uncontrollable ? ? ?

Absolutely not.

You just have to know what you're doing.
I realize that's fallen out of favor in the 21st Century, but it's still valid.

- Leigh

?????????

Bill Burk · May 14, 2017

Getting back to the original question...

Yesterday on a dayhike with the scouts I put Panatomic-X in the camera, and attached a yellow filter.

I know from sensitometric tests that this film achieves its full rated speed despite its advanced age, which means it "starts out at" a real rating of EI 32

When using Zone System metering technique, I change the meter EI by 2/3 stop (This 2/3 stop is settled in my own mind as a plain and simple fact, proven over the course of many long discussions)... EI 20

Then the yellow filter knocks off a stop: EI 10

Now that's a heck of a slow speed to be shooting at. Had to use the tripod and kids had to hold still.

But it puts the exposure up on the straight line where I like it.

Stephen Benskin · May 14, 2017

jernejk said:
I've been re-reading through some theory and technicalities, and as far as I understand, metering and exposing for an 18% grey card (or using incident meter) will put that zone V at 0.7 density, assuming box speed and normal development time, right?

Now, looking at the data shets of tmax, trix and delta 400, that's roughly just about 2 or 3 stops from the toe. On the other hand, there are at lest 6 stops still available above zone V, which makes no sense for most subjects.

Using a spotmeter, one can of course measure for the shadows and put those in say zone IV (as actually suggested by Bruce Burnbaum on youtube), which would move Zone V to at least Zone VI.

But essentially it seems to me these modern films have so much dynamic range, one could (or should even!) shoot them at ISO 100 and simply measure the light with incident light meter/grey card, and for 80-90% of the scenes the negative will be just fine. On the other hand, shooting at box speed using that method will always lose some shadow details.

Am I correct or did I miss something?

Take a look at the attachment Zones.png. Between Zone I and II is the notation Hm. This is the speed point. The equation is Speed = 0.80 / Hm. For a 100 speed film Hm equals 0.008 lxs.

The exposure for B&W at the meter reading is 10X Hm or 0.08 lxs. This attachment might help with the relationships. It's for a 125 speed film.

Bill Burk · May 14, 2017

Thanks Stephen,

I needed this diagram to figure out that with a 100 ftL reference light source, with ASA 32 film in my camera... where the metered point is f/16... I should expose for about 1 second to confirm the light source, and if that checks out, then I should make sure the meter says the same thing.

If Zone V is density 0.7, aren't we throwing much of the dynamic range away?

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If Zone V is density 0.7, aren't we throwing much of the dynamic range away?

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