Roger Hicks
Veteran
If you want to control contrast, you need to know the subject brightness range. The only way to be sure of this is to read both the darkest shadow in which you want texture and detail and the brightest highlight in which you want texture and detail. Far and away the easiest way to do this is with a spot meter.
For many years, my view has been that by the time you understand enough abouit basic sensitometry to get any benefit from the Zone System, you should know enough not to need it. You might (or might not) find the following views of the Zone System to be of use:
http://www.rogerandfrances.com/subscription/ps zone.html
http://www.rogerandfrances.com/subscription/zone system.html
Cheers,
R.
lilmsmaggie
Established
From a practical standpoint, I agree. But for the OP's sake, it doesn't hurt to have a basic understanding of the Zone System since the OP seems geniunely interested. There is value in understanding the system even if one's objective is not delving into sensitometry, densitometry, etc. etc
As far as I'm concerned, all that scientific mumbo-jumbo takes the fun out of photography.
Personally, I don't use the Zone System either - at least not on a conscientious level. I understand the concept but I don't obsess in the mechanics and methodology.
Based on advice from one of Ansel's assistants, If I'm shooting B&W, I expose for the darkest shadow detail I want to be able to see in the print. If shooting color, I expose for the highlights.
The Fred Picker Book that the OP is reading attempts to assist the uninitiated in determing their individual film speed and using a methodology for testing exposure and processing film. Whether you like Picker's approach or not is a personal thing but there is more value than harm in reading the book.
The whole point of Picker's book and others who have written on the Zone System including AA himself is an attempt to provide the photographer with a tool that will allow them to achieve consistent, predictable results.
And that my friends takes time and experience.
ferider
Veteran
There is a compromise between the two, and I am always suprised that nobody else seems to use it - i couldn't live without it:
You walk through the woods and see a nice scene. You take your digital Gossen, wave it around (reflective) and read the contrast range, which most digital Gossens show nicely. Than you pick the "right" exposure/zone/.... from the meter.
Roland.
Roger Hicks
Veteran
Dear Roland,
Absolutely, but with a slight addition. If you want to give due weighting to the deep shadows, then make sure you read them from reasonably close up.
ANY metering system can be made to work, with a bit of intelligence and interpretation. Trying to fit Zone System jargon to most real-world metering systems is doomed to failure, especially if applied without understanding.
Zones are after all print values: you can print Zone V from two completely different densities on a negative, merely by varying the print exposure. Where the other Zones will 'fall' (and whether or not there is any density whatsoever in what the photographer hoped would be Zone III) is another matter entirely.
Fortunately, neg/pos photography is sufficiently flexible that it can usually accomodate the error introduced by would-be Zone System aficionados who don't actually understand the Zone System. Anyone who understands anything about photography can use your system quickly and easily, with latitude taking care of the vast majority of minor errors that could theoretically arise from such an apparently casual approach.
Cheers,
R.
bwidjaja
Warung Photo
Not meaning to hijack the thread, but this topic about exposure has been in my mind lately. Here is a related question, though not necessarily Zone System.
For Chris, when you said you never needed N+1, I assume you don't mean that in the sense of never needing to "push" process. For example using Tri-X for a low light scene at EI800 and push process N+1. Please correct me if I am wrong.
For others, 2 questions:
1. I read (could not find the thread) about expose for the shadow and develop highlight. One thing I have a hard time understanding is the Normal part of Overcast, Normal, Sunny/Contrasty. I am not sure what Normal Contrast means in this case. Maybe scene example is helpful.
2. Assuming using a roll film with mixed flat and contrasty lighting, what do you recommend for exposure compensation between the two lighting condition; given the development is N.
Thank you,
Berhen
For Chris, when you said you never needed N+1, I assume you don't mean that in the sense of never needing to "push" process. For example using Tri-X for a low light scene at EI800 and push process N+1. Please correct me if I am wrong.
For others, 2 questions:
1. I read (could not find the thread) about expose for the shadow and develop highlight. One thing I have a hard time understanding is the Normal part of Overcast, Normal, Sunny/Contrasty. I am not sure what Normal Contrast means in this case. Maybe scene example is helpful.
2. Assuming using a roll film with mixed flat and contrasty lighting, what do you recommend for exposure compensation between the two lighting condition; given the development is N.
Thank you,
Berhen
lilmsmaggie
Established
Oh-oh There's that word "normal." I ain't touching that one. I'm already in enough trouble with Roger
skibeerr
Well-known
Very hard contrast scene. (hard direct light)
Strong sunlight around noon. The whites/highlights exposed to the sun reflect mucho light, dark objects in the shadow get nada they are very dark (if no reflecting surface is near)
Very flat light. (diffused light)
A foggy morning, the feeble morning sunlight is reflected on the waterparticels in the air, in all directions (there are no visible shadows) everything receives an even light.
Now good old Ansel Adams explains in "the negative" that tough you can retrieve a lot out of a negative by dodging and burning it is desirable that the negative represents an as close as possible representation of the scene/print you had in mind. (In an ideal world, smak the neg in the carrier, expose paper and done)
So what is normal
(@Roger, you will love these "the science of Discworld" lies to....)
You got your zone's bar you measure your highlight put them on zone IX now you measure the darkest part, if the difference in stops is so that the measurement of the dark part fals on I you'v got Normal.
If these measurments go beyond the zone bar you have to much contrast if they fall say on II and VIII you have a flat contrast and here N+ and N- come in.
This is what Christopher means with N+1 for a flat scene (but he lives where the sun always shines) mostly an increase of 20 to 30% of the dev with the darkest part on zone I
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Roger Hicks
Veteran
'Normal' is indeed a wonderful concept. ISO standard contrast is about 0.62 (i.e. an increase of 0.62 log density units per log unit of increased exposure) because this gives a negative that will print an 'average' outdoor scene in the area around Rochester, New York, on a midding grade of paper (grade 2 or 3).
But it tends to be sunnier in Japan, so you need less contrasty negatives: if you develop your Japanese negatives to ISO standard contrast, you will need grades 1 and 2. The Japanese members of the ISO standards committee therefore lobbied for a lower contrast (0.56, as far as I recall).
In other words, negative density range is a product of subject brightness range (SBR) and negative development time (more time = more contrast, less time = less contrast). A longer SBR demands less development time for a given negative density range: a shorter SBR, more development time.
To make life still more interesting, we have the lens flare factor to consider. The image thrown upon the film will always be less contrasty than the SBR. If it were identical, the flare factor would be 1, and an SBR of (say) 256:1 (8 stops) would be reproduced as an image of 256:1 (8 stops). A multicoated lens with few elements, in a new LF camera with well-blacked bellows, can come close to 1 but can never reach it. An old zoom in a well-used SLR may well have a flare factor as high as 4. In other words, the image brightness range would be reduced to 64:1 (6 stops). Obviously the lower-contrast image needs to be developed for longer in order to get a negative of the same density range as the high-contrast image.
A 'normal' paper grade will reproduce a negative density range of about 3-4 stops (log density range 0.9, for Grade 3, to 1.2, for Grade 2) as a full range of tones from pure white to maximum black. If the SBR is (say) 128:1 (7 stops, log brightness range 2.1) and the lens has a flare factor of 2 then the projected image brightness range is 64:1 (6 stops, log range 1.8). For a negative density range of 0.9 you need a contrast of 0.9/1.8 = 0.5 and for a negative density range of 1.2 the contrast needs to be 1.2/1.8 = 0.67. All these numbers are rounded for ease of calculation, but they are in the right ball-park.
If the negative density range is less than 0.9 to 1.2, you need harder paper; if it is more, you need softer. Alternatively, you can increase the density range of the negative with more development ("N+ development", in Zonespeak), or you can decrease it with less ("N- development"). If you have a mixture of SBRs on one roll, you can accommodate them with 'normal' development and different paper grades. "Normal", in this context, simply means "the majority of negatives of the sort of subjects you normally shoot will print on grades 2 and 3".
It is perfectly possible to learn all that you need empirically: "suck it and see". Many first-class photographers do this. There are, therefore, only two reasons to study sensitometry, ISO standards, etc. One is that it interests you, and the other is because it's part of your job (as in my case). Once you have studied it, though, think of the Zone System being a small subset of sensitometry, beset with jargon, overcomplicated in some ways and oversimplified in others.
Cheers,
R.
But it tends to be sunnier in Japan, so you need less contrasty negatives: if you develop your Japanese negatives to ISO standard contrast, you will need grades 1 and 2. The Japanese members of the ISO standards committee therefore lobbied for a lower contrast (0.56, as far as I recall).
In other words, negative density range is a product of subject brightness range (SBR) and negative development time (more time = more contrast, less time = less contrast). A longer SBR demands less development time for a given negative density range: a shorter SBR, more development time.
To make life still more interesting, we have the lens flare factor to consider. The image thrown upon the film will always be less contrasty than the SBR. If it were identical, the flare factor would be 1, and an SBR of (say) 256:1 (8 stops) would be reproduced as an image of 256:1 (8 stops). A multicoated lens with few elements, in a new LF camera with well-blacked bellows, can come close to 1 but can never reach it. An old zoom in a well-used SLR may well have a flare factor as high as 4. In other words, the image brightness range would be reduced to 64:1 (6 stops). Obviously the lower-contrast image needs to be developed for longer in order to get a negative of the same density range as the high-contrast image.
A 'normal' paper grade will reproduce a negative density range of about 3-4 stops (log density range 0.9, for Grade 3, to 1.2, for Grade 2) as a full range of tones from pure white to maximum black. If the SBR is (say) 128:1 (7 stops, log brightness range 2.1) and the lens has a flare factor of 2 then the projected image brightness range is 64:1 (6 stops, log range 1.8). For a negative density range of 0.9 you need a contrast of 0.9/1.8 = 0.5 and for a negative density range of 1.2 the contrast needs to be 1.2/1.8 = 0.67. All these numbers are rounded for ease of calculation, but they are in the right ball-park.
If the negative density range is less than 0.9 to 1.2, you need harder paper; if it is more, you need softer. Alternatively, you can increase the density range of the negative with more development ("N+ development", in Zonespeak), or you can decrease it with less ("N- development"). If you have a mixture of SBRs on one roll, you can accommodate them with 'normal' development and different paper grades. "Normal", in this context, simply means "the majority of negatives of the sort of subjects you normally shoot will print on grades 2 and 3".
It is perfectly possible to learn all that you need empirically: "suck it and see". Many first-class photographers do this. There are, therefore, only two reasons to study sensitometry, ISO standards, etc. One is that it interests you, and the other is because it's part of your job (as in my case). Once you have studied it, though, think of the Zone System being a small subset of sensitometry, beset with jargon, overcomplicated in some ways and oversimplified in others.
Cheers,
R.
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tlitody
Well-known
Here's a little something for you to consider.
If Zone V is 18% reflectance then zone VI would be twice that at 36% reflectance. And Zone VII would be twice that at 72% reflectance. And Zone VIII would be twice that at 144% refelctance. Now if you can explain to me how its possible for Zone VIII to reflect 144% of the light falling on it then I will be impressed.
Fact is that 18% reflectance is always 2 1/2 stops less than 100% reflectance. That's the simple plain facts. In a 10 Stop range and assuming Zone 10 is 100% reflectance, then 18% would be zone 7 1/2. On a 8 stop range it would be zone 5 1/2. And on a 5 Stop range it would be zone 2 1/2 which is infact the middle of the range and is the only case where it is the middle of the range. This assumes 1 zone = 1 stop.
Just to complicate it further for you. The ISO standard only uses approx an 8 Stop range to achieve its standard contrast index on negative films. When you apply the zone system to that and using 10 zones, then can consider each zone to be only 0.8 stops and not 1 stop. When you do that you find that zone 7 is 5.6 ( 7x 0.8) stops of range. Well 18% of 8 stops is 2 1/2 stops less which is 5 1/2 stops which is damn close to 5.6. So infact when using manufacturers standard dev and ISO box speed for neg film, your meter calibrated to 18% reflectance is actually giving you a reading for around zone VII and not V.
So there is no such thing as a basic understanding of the zone system because it is propagated by people who don't understand it themselves. And AA is largely to blame for this because if you read his books you will think that 18% is a zone V value. Well it isn't except when you are dealing with a 5 stop range.
But don't assume your meter is calibrated for 18% because most aren't, epecially in camera meters which is why a lot of us like to use handheld meters. But it really doesn't matter what your meter is calibrated to because through testing and working out our own exposure index (EI), we can arrive at correct metering and devlopment without any knowledge of the above.
You just need to have faith in a reliable testing procedure and metering technique which is really very simple.
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srtiwari
Daktari
Lets try this again ! The horse is not quite dead yet !
Lets try this again ! The horse is not quite dead yet !
This has been an interesting thread- as I should have known, there would be lots of disagreement among 'experts'.
Let me see if I can make it useful for myself again.
My reason for posing the question was based on a simple premise; Incident and reflected are both methods used by many to calculate exposures. Both 'read' the light and express output in terms of exposure settings. The readings are to be interpreted in some way and applied to camera settings in the hope of producing some kind of desirable exposure on film.
Reflected meters read light too, except this is reflected from the subject, the reflectance of which needs to be approximated, so that the readings can be applied to the scene.
Now, I am very aware that there can be great variation brightness between different 'zones' (dare I say it ?) of the scene, and that this (partly/entirely ?) contributes to a lesser or greater degree of range of contrast.
So far so good !
Even with incident light readings one has to determine the 'ideal' exposure, based on visually assessing which part of the picture would appear 'middle gray' with THAT particular setting. I imagine one has to do something similar with reflected readings from different brightnesses in the picture.
So... my question was (and is) this is there no 'parity' (sorry, can't think of another word right now) between incident meter reading, and a mid-toned (middle gray ?) part of the scene ? This would suggest there is nothing to 'think' when using an Incident meter. And if so, how would anyone find Incident metering useful at all ?? And of course this applies equally to all those expert enough to not need a meter at all !!
And this IS the part I find intriguing. Two readings obtained via the same light measuring technology, CANNOT be translated from one to any part of the other, even though we are familiar with how they are different.
I am willing to accept that they cannot be translated, but can't see why.
Any simple answers out there ?
Lets try this again ! The horse is not quite dead yet !
This has been an interesting thread- as I should have known, there would be lots of disagreement among 'experts'.
Let me see if I can make it useful for myself again.
My reason for posing the question was based on a simple premise; Incident and reflected are both methods used by many to calculate exposures. Both 'read' the light and express output in terms of exposure settings. The readings are to be interpreted in some way and applied to camera settings in the hope of producing some kind of desirable exposure on film.
Reflected meters read light too, except this is reflected from the subject, the reflectance of which needs to be approximated, so that the readings can be applied to the scene.
Now, I am very aware that there can be great variation brightness between different 'zones' (dare I say it ?) of the scene, and that this (partly/entirely ?) contributes to a lesser or greater degree of range of contrast.
So far so good !
Even with incident light readings one has to determine the 'ideal' exposure, based on visually assessing which part of the picture would appear 'middle gray' with THAT particular setting. I imagine one has to do something similar with reflected readings from different brightnesses in the picture.
So... my question was (and is) this is there no 'parity' (sorry, can't think of another word right now) between incident meter reading, and a mid-toned (middle gray ?) part of the scene ? This would suggest there is nothing to 'think' when using an Incident meter. And if so, how would anyone find Incident metering useful at all ?? And of course this applies equally to all those expert enough to not need a meter at all !!
And this IS the part I find intriguing. Two readings obtained via the same light measuring technology, CANNOT be translated from one to any part of the other, even though we are familiar with how they are different.
I am willing to accept that they cannot be translated, but can't see why.
Any simple answers out there ?
Roger Hicks
Veteran
Dear Subhash,
Do you accept that the ideal exposure for a negative is usually based on getting enough exposure in the darkest areas in which you want shadow and detail? (This is after all the basis of all film speed systems.)
Any further explanation depends on the answer to this question.
Cheers,
R.
Do you accept that the ideal exposure for a negative is usually based on getting enough exposure in the darkest areas in which you want shadow and detail? (This is after all the basis of all film speed systems.)
Any further explanation depends on the answer to this question.
Cheers,
R.
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srtiwari
Daktari
I do. ( I feel like Pr.William now !)
Roger Hicks
Veteran
Good.
The only way to determine the brightness of the darkest area in which you want texture and detail is to read it directly (spot reading).
All other approaches infer the brightness of the darkest area in which you want texture and detail, because they do not measure it directly.
Based on experience, you can infer that brightness via a very large number of methods. That's why almost all metering methods can be made to work.
Take an incident light reading, or read a grey card, and you can infer that you will get adequate shadow detail in absolutely flat lighting with no shadows, because nothing reflects that much less light than an 18% grey card, and for all that an incident light dome is an 'artifical highlight', there's also an ND component for convenience in meter manufacture and scaling.
But as soon as there are any shadows, a lot depends on how dark they are, and how important they are. Hence the example of the tree roots. There is less light under the roots than in the scene as a whole: they are in shadow.
You can guess how much the light is reduced by the shadow, based on experience. Or you can read it directly...
Does it make sense now?
Cheers,
R.
tlitody
Well-known
Because different parts of the scene are in different lighting. For example, one area in direct sunlight, the other area in deep shade(reflected) sunlight. The reading from one light source doesn't translate to the other light source. There is no measure of how much light is being reflected to do the translation with.
So you have to measure both, set exposure based on the darker area and adjust development to control the lighter area.
Freakscene
Obscure member
I use N+ development often; in Summer here, often near the water, sometimes the light is f8 or 11 @ 1/1000 Ei320, but the subjective brightness range of my subjects can be 2-4 stops. It's common for me, but I can see how it might be rare for others. Bright but even light seems to be something I know well that it almost unknown in most other places.
Chris is very organised - as am I - most people who I have tried to teach this system get hopelessly confused about which rolls are which. It works okay with traditional 400 speed films if you develop everything at between N and N-1 but vary your exposure for the light.
Marty