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  1. #161

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    I think I'm getting closer to really understanding this.

  2. #162
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    Quote Originally Posted by Michael R 1974 View Post
    I think I'm getting closer to really understanding this.
    You've got me doing some thinking.
    Last edited by Stephen Benskin; 01-27-2013 at 05:58 PM. Click to view previous post history.

  3. #163

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    Makes me feel a little better about repeatedly asking questions that should probably be basic. I appreciate you not giving up on my flare effect questions. Thanks to Bill also. I understand what non image forming light is, where it can come from, and it's effects on the characteristic curve. But I'm often less clear on assessing a specific situation (my in-camera/white card scenario for example). I'm prone to doing these sorts of "thought experiments" - call it scenario analysis - to see if I truly understand how to apply a concept. That is, can I look at a photographic situation and figure out if it is at least high or low flare. And actually I find film testing scenarios/setups more difficult to assess than most real photographic situations.

    The concept of flare is usually not taken that far in photographic texts (including Henry). I wish most texts went beyond the effects on the curve and gave some practical examples/scenarios. Then again, no information is probably better than bad information. The Book of Pyro, for example, contains some flare rules of thumb I'm not sure are accurate at all. As much as I am a fan of Adams, I think the subject of flare is a real shortcoming of The Negative. It is mentioned in little more than a cursory way, but can be a major source of distortion in Zone System testing and applications. It seems like something that should be given a full explanation even if we can't control it.

    Apologies again for pausing the thread on this particular variable.
    Last edited by Michael R 1974; 01-27-2013 at 07:08 PM. Click to view previous post history.

  4. #164
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    Quote Originally Posted by Michael R 1974 View Post
    As much as I am a fan of Adams, I think the subject of flare is a real shortcoming of The Negative. It is mentioned in little more than a cursory way, but can be a major source of distortion in Zone System testing and applications. It seems like something that should be given a full explanation even if we can't control it.
    Just my thoughts here, nothing critical. My views are geared more toward practicality, which the newcomer or first-timer parusing these threads must never, never, ever lose sight of, in the midst of all this theory.

    Your're right, it is not mentioned to any appreciative manner that even remotely resembles the type of discussions that occur here, yet his work speaks for itself, how important was it to him, I don't know, just asking. It begs the question, in my mind, as to just how important it really is in practical film testing for EI and N-times. It makes for discussion, and I do follow it, but just how important is it? This is not to imply that I think it has no affect, only that it's affect, has got to be so dependent on "degree" as to not warrant much consideration in the intellegent use of the Zone System.

    From The Negative, Appendix 1, regarding testing (I'm sure you've seen it, but it makes my point): "Choose a film and developer you use often, and be sure to use the same camera, shutter and lens throughout. Your exposure meter, lens diaphragm, shutter, and darkroom thermometer must be reliable----calibrated by a technician if possible. Once this "system" has been tested, any variations introduced by a change of equipment (such as the possible difference in aperture calibration or flare introduced by changing lenses) should be quite apparent if they are significant. For a change in film and/or development, of course, new tests must be conducted."

    So, essentially, flare, if significant, should be apparent with intelligent use of the ZS or any system and in that respect I fail to see any distortion in testing or application. I consider myself a competent ZS user and I simply have not been able to make a determination that flare is "apparent" in my "system", even though I'm fully aware that the tests I carry out (an in-camera contacted step tablet, exposed to Zone X to an evenly and diffusely illuminated single tone test target) are flare free. I make a decision before releasing the shutter as to what measure I may take to deal with possible flare influences, it is a negative by negative consideration and I rarely do anything different, and when I do, it is usually a -1/3 to -2/3 reduction in exposure. When compensating for it or not, the desired print is always obtainable as envisioned, flare has not seemed to affect the end result. If I had an older uncoated lens and switched from my new Nikkor to it, well then, it would be "apparent", even before exposure, that flare is going to affect my "placement".

    So I disagree with your statement, but given the spirit of the discussion I understand why you make it. In keeping with the OP, I would say to those wishing to carry out film tests for themselves for the first time, to just do it. Find a source i.e., BTZS, The Negative, Schaeffer, Lambrecht----follow it, and it only, to the "T" and be careful of outside advice, it is sure to trip you up. As one understands the concept of "expose for the shadows and develop for the highlights"----which the ZS and BTZS are simple vehicles toward that end, then one already has all they need to know to know how to deal with flare. At that juncture, flare in testing for EI becomes a mute point and you are assured that flare in actual photographing is intelligently dealt with.

    Just my opinion folks.

  5. #165
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    Originally Posted by Stephen Benskin
    Every successful photograph I make shows theory. Isn't that the foundation of your defense of the Zone System? The quality of Ansel Adams' work is proof of the theory.

    Originally Posted by CPorter
    Putting it in terms of theory is certainly acceptable, but the foundation of my defense of the Zone System lies in learning how valuable (to me) the process of visualization can be. My photographic "craft" is leaps and bounds from what is was, because of the Zone System, and being proficient in the craft of photography is the path to becoming better at visualization, IMHO.

    Quote Originally Posted by CPorter View Post
    Your're right, it is not mentioned to any appreciative manner that even remotely resembles the type of discussions that occur here, yet his work speaks for itself, how important was it to him, I don't know, just asking.

  6. #166

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    Hi CPorter,

    I guess all I'm saying is that in The Negative (and many other books, articles etc) flare should be explained, particularly because the recommended film testing methodology does not involve contacting a step tablet. So it again comes back to the interpretation of test results. The effects of non image forming light might be useful to the reader when looking at the curves generated.

    Let me ask you this - why a 1/3 to 2/3 stop reduction in exposure when you suspect significant flare effects?

    Michael

  7. #167
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    Quote Originally Posted by Michael R 1974 View Post
    Hi CPorter,

    I guess all I'm saying is that in The Negative (and many other books, articles etc) flare should be explained, particularly because the recommended film testing methodology does not involve contacting a step tablet. So it again comes back to the interpretation of test results. The effects of non image forming light might be useful to the reader when looking at the curves generated.

    Let me ask you this - why a 1/3 to 2/3 stop reduction in exposure when you suspect significant flare effects?

    Michael
    For one explanation see Dunn & Wakefield Exposure Manual, in edition 3 there is an explanation with graph on page 19.

    Essentially flare lifts the toe of the curve more and more as exposure rises reducing effectively contrast on the film. Lower exposure levels when there is significant flare can provide better separation of tones.
    Mark Barendt, Ignacio, CO

    "We do not see things the way they are. We see things the way we are." Anaïs Nin

  8. #168
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    "Choose a film and developer you use often, and be sure to use the same camera, shutter and lens throughout. Your exposure meter, lens diaphragm, shutter, and darkroom thermometer must be reliable----calibrated by a technician if possible. Once this "system" has been tested, any variations introduced by a change of equipment (such as the possible difference in aperture calibration or flare introduced by changing lenses) should be quite apparent if they are significant. For a change in film and/or development, of course, new tests must be conducted."

    Adams' description here may appear 'wooly' in terms of flare but the key sentences are:

    "be sure to use the same camera, shutter and lens throughout" - the reason for this is that the testing procedure automatically compensates for flare.

    "any variations introduced by a change of equipment (such as the possible difference in aperture calibration or flare introduced by changing lenses) should be quite apparent if they are significant." - i.e if you have calibrated with one camera, one lens, one meter, one developer, one thermometer, etc introducing a variable such as a different lens will immediately show if flare, for example, is a significant factor. If it is, you then know that you need to re-calibrate for that particular lens by redoing the testing sequence.

    Often, particularly with 35mm/roll film users, you will hear comments such as 'my 28mm lens is rather soft compared to my other lenses'. This is actually the photographer describing that a particular lens has more flare (or indeed a different level of coating on the lens) than the others.

    A friend of my father - the late photographer James Ravilious - was unhappy with his Leica kit. The reason for this was that he couldn't consistently get the particular results he wanted. James preferred the softer look of older Leitz lenses before the advent of computer re-calculation and multiple coatings on the lenses. His problem was easily solved by getting rid of the newer lenses and buying lenses from the late 1950s. These gave the 'look' that he wanted with consistent tonality. In effect a matched set of lenses that all demonstrated the same level of flare which meant he could do one set of tests and then move on without having to worry.

    The lesson here is that, for 35mm and roll film users especially, the goal should be to get a matched set of lenses. In doing so, one can disregard all of the additional theory and get on with the most important aspect of photography - enjoying it!

    Best,

    David
    www.dsallen.de

  9. #169
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    David I agree with your Analisys of Adams' method and the observation about how lenses affect the result but a matching set of lenses?

    Much of the reason I settle on various lenses is to get various qualities, much more than a focal length change. Mamiya's 150SF is a great example. It can be adjusted to be sharp, f8 or smaller varying amounts of soft can be dialed in as needed with larger apertures, its an exceptional goto lens for portraits and landscape and snaps. This provides for a bit more work when printing but that's ok.
    Mark Barendt, Ignacio, CO

    "We do not see things the way they are. We see things the way we are." Anaïs Nin

  10. #170

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    Quote Originally Posted by markbarendt View Post
    For one explanation see Dunn & Wakefield Exposure Manual, in edition 3 there is an explanation with graph on page 19.

    Essentially flare lifts the toe of the curve more and more as exposure rises reducing effectively contrast on the film. Lower exposure levels when there is significant flare can provide better separation of tones.
    I know the effects on the curve. I'm challenging the notion reduced exposure can provide better separations. To me it seems like if anything it would have the opposite effect since it shifts more of the exposure values into the part of the curve where compression is taking place.

    Regarding the sources of flare in testing etc, again, I'm refering mostly to flare caused by the subject/test target, not the lens. The kind of "veiling" lens flare Adams refers to is likely a relatively minor issue with most contemporary lenses.
    Last edited by Michael R 1974; 01-28-2013 at 07:06 AM. Click to view previous post history.



 

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