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Thread: BTZS vs Zone? Incident v

  1. #1

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    BTZS vs Zone? Incident v

    OK someone explain to me the difference between BTZS and the Zone system.
    I understand the Zone System conceptually - expose for the (relevant) shadows by metering the shadows and setting them as Zone V and figure out the luminance range by metering highlights, develop for the (relevant) highlights by adjusting development time for the corresponding luminance range. So how is that different from BTZS?

    Also, somethign else I am having problems understanding conceptually: incident light meters and reflected lightmeters are both calibrated to the 18% gray standard. Thus, the meter reading on an incident light meter should result in gray subjects, right? A white cat in the snow would come out ...gray? There are people who claim that you don't have to worry about that when using incident light meters, only with reflected lightmeters.
    Last edited by cyrus; 27-Aug-2006 at 18:18.

  2. #2

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    Re: BTZS vs Zone? Incident v

    I can help with the incident meter but I do not belong to the BTZS church. Incident meters measure the light, not the reflected light, so they read the same regardless of the subject. Thus your white cat is white because it reflects more light than the grey card or the coal bin. Reflected light meters read the light coming back from the subject, thus everything is normalized to grey. The cat will get a higher reading than the coal bin, although they are in the same light.

  3. #3
    Whatever David A. Goldfarb's Avatar
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    Re: BTZS vs Zone? Incident v

    Quote Originally Posted by cyrus
    OK someone explain to me the difference between BTZS and the Zone system.
    I understand the Zone System conceptually - expose for the (relevant) shadows by metering the shadows and setting them as Zone V and figure out the luminance range by metering highlights, develop for the (relevant) highlights by adjusting development time for the corresponding luminance range.
    Normally ZS practitioners would place the shadows (the darkest area that should show detail in the print) on Zone III, or maybe IV depending on the film.

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    Re: BTZS vs Zone? Incident v

    Rather than go into this again with the same people let me point interested parties to a few resources on BTZS.

    www.btzs.org is the official site of BTZS and Phil Davis, who created BTZS, is there to answer questions. Davis is also the author of Beyond the Zone System, which fully explains the theory and practice of BTZS.

    Also, there have been quite a number of threads on this forum during the past year that one could read to get an idea of the pros and cons and some sense of the working procedures. Two that might be of interest are below.

    http://www.largeformatphotography.in...highlight=BTZS

    http://www.largeformatphotography.in...highlight=BTZS

    Sandy King
    Last edited by sanking; 27-Aug-2006 at 20:04.

  5. #5

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    Re: BTZS vs Zone? Incident v

    Quote Originally Posted by David A. Goldfarb
    Normally ZS practitioners would place the shadows (the darkest area that should show detail in the print) on Zone III, or maybe IV depending on the film.
    Ooops - sorry my typo.

  6. #6

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    Re: BTZS vs Zone? Incident v

    "OK someone explain to me the difference between BTZS and the Zone system.
    I understand the Zone System conceptually - expose for the (relevant) shadows by metering the shadows and setting them as Zone V and figure out the luminance range by metering highlights, develop for the (relevant) highlights by adjusting development time for the corresponding luminance range. So how is that different from BTZS?"

    You're asking quite a lot because to fully understand the differences you need to first understand both the zone system and the BTZS system. Entire books have been devoted to both subjects. I don't personally feel up to the task of doing all that in a message here, perhaps someone else will or better yet you can check out the references Sandy has provided.

    I can tell you in the smallest of nut shells that the BTZS system consists of a combination of equipment (hardware and software) and techniques that together are used to test film and to determine the appropriate exposure, development time, and paper exposure scale for a given image. Differences between it and the traditional zone system include (1) the method used to test film, (2) the method used to determine development times, and (3) if you use an incident meter, the method used to determine exposure. If you use a spot meter the method used to determine exposure is the traditional zone system except that instead of doing things in your head you enter the usual zone system information into a Palm Pilot loaded with a program written by Phil Davis, the "inventor" of BTZS, and the computer tells you what shutter speed to use for the aperture you've selected or vice versa. The same computer is used with an incident meter (the program asks you early on which type of meter you're using) but I don't know what happens when you tell it you're using an incident meter, I always used a spot meter.

    The computer also tells you the subject brightness range of each image which is used, after appropriate BTZS testing, to determine the development time. In addition, the computer can be used for other things not directly related to BTZS (e.g. it can be used to automatically adjust the exposure for bellows extension and filter factors, it provides depth of field information, it serves as a timer and record-keeper, and a bunch of other things I don't now remember).

    I hope that's useful. I last used the BTZS system about six years ago so I've forgotten a lot. Hopefully my very brief summary is basically accurate but if it's not anyone more current and knowledgeable than I am is certainly welcome to correct me.
    Brian Ellis
    Before you criticize someone, walk a mile in their shoes. That way when you do criticize them you'll be
    a mile away and you'll have their shoes.

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    Re: BTZS vs Zone? Incident v

    Quote Originally Posted by sanking
    Rather than go into this again with the same people let me point interested parties to a few resources on BTZS.

    www.btzs.org is the official site of BTZS and Phil Davis, who created BTZS, is there to answer questions. Davis is also the author of Beyond the Zone System, which fully explains the theory and practice of BTZS.

    Also, there have been quite a number of threads on this forum during the past year that one could read to get an idea of the pros and cons and some sense of the working procedures. Two that might be of interest are below.

    http://www.largeformatphotography.in...highlight=BTZS

    http://www.largeformatphotography.in...highlight=BTZS

    Sandy King
    Yeah I did check the threads and wasn't terribly enlightened. I was hoping someone could just give me the "broad concepts" view of BTZS and I'll figure out the details later (I have the BTZS books & I have been reading up - thus far, its just a review of reading the HD curve...)

    So as far as I understand the BTZS is essentially the same as the Zone Sytem, except more "scientific" because they use denistometers and computers to handle the data. That's it?

    Being somewhat of a "professional life-long student" in a wide variety of fields, I have found out that I can learn something best when I first get the "big picture" down, then I will fill out the details later - and the best teacher IMHO is someone who can systematically present the "woods" before presenting the "leaves" [I can also spot someone who knows actually knows what they're talking about when they can state the concept clearly in a single sentence.]
    Last edited by cyrus; 27-Aug-2006 at 21:31.

  8. #8

    Re: BTZS vs Zone? Incident v

    So as far as I understand the BTZS is essentially the same as the Zone Sytem, except more "scientific" because they use denistometers and computers to handle the data. That's it?
    No, that is not it. Read Brian's response, I think he did a very good job explaining it in a nut shell.

    BTW, the ZS as explained by Adams also uses a densitometer, just not as intensively as the BTZS.
    Last edited by Jorge Gasteazoro; 27-Aug-2006 at 21:38.

  9. #9
    Kirk Gittings's Avatar
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    Re: BTZS vs Zone? Incident v

    I am feeling like taking some shortcuts tonight as I still have a couple of hours of work to do. So I am quoting myself from the other thread.

    The viability of BTZS is really not a question anymore. It has a proven track record. The real question, at least in my mind, is whether it offers any real advantages over the Zone System or whether it just ads more levels of complication.

    For instance it separates film speed/film developing testing from the variances of meter accuracy, shutter speeds etc. That to me is not an advantage over the ZS, but some see it so. Some BTZS practitioners also see it as simpler system yet recently three BTZS practitioners in these threads many have admitted that they carry both an incident meter and a spot meter plus a palm pilot in the field to cover all the bases. That does not sound simpler. I have never had to carry more than a spot meter and a pencil with the ZS. I for one am loath to carry any more equipment than I have now.

    I have read all of Jorge's comments on using incident meters on the BTZS blog. It is clear from those dialogues that an incident meter requires a fair amount of field experience to use one well. It doesn't sound any easier than a spot meter which has its own little quirks.

    It is obvious that both systems work. I suspect that any careful worker with real vision could turm out great work with either system. The real enemy is lack of vision and poor work habits.
    Thanks,
    Kirk

    at age 73:
    "The woods are lovely, dark and deep,
    But I have promises to keep,
    And miles to go before I sleep,
    And miles to go before I sleep"

  10. #10

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    Re: BTZS vs Zone? Incident v

    Quote Originally Posted by Kirk Gittings
    For instance it separates film speed/film developing testing from the variances of meter accuracy, shutter speeds etc. That to me is not an advantage over the ZS, but some see it so. Some BTZS practitioners also see it as simpler system yet recently three BTZS practitioners in these threads many have admitted that they carry both an incident meter and a spot meter plus a palm pilot in the field to cover all the bases. That does not sound simpler. I have never had to carry more than a spot meter and a pencil with the ZS. I for one am loath to carry any more equipment than I have now.

    I have read all of Jorge's comments on using incident meters on the BTZS blog. It is clear from those dialogues that an incident meter requires a fair amount of field experience to use one well. It doesn't sound any easier than a spot meter which has its own little quirks.
    You can use whatever system of metering you want in the field. As Brian made clear last evening, both Zone type metering and incident type metering is encompassed by BTZS. I personally use a Sekonic L-508, which is both a spot meter and an incident meter. And I use both types of metering on a regular basis. And although some use a PDA or pocket computer to calculate exposure and develoment information in the field, I don't as I find it distracting and not really necessary for most work.

    The essence of BTZS is in its testing methodology, which is faster, more precise and gives more information than traditional Zone type testing. I doubt anyone who has actually learned BTZS would disagree with this statement. Of course, if one only uses one or two films and has been using the same ones for the past quarter century, a more efficient method of testing might not be high on the list of priorities. But for photographers just learning to expose and develop sheet film who use several different films and like consistency in their exposures and develoment, the more efficient testing of BTZS might be important.

    Neither system makes you more creative, and both require as an absolute that you test your materials, and that you know how to meter the subject, whether it be with a spot or incident meter.


    Sandy
    Last edited by sanking; 27-Aug-2006 at 23:32.

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