Garyh I completely agree that reflective metering can be a great tool but not that it can be more accurate, equal sure but not more.
What I will say is that each method requires a different mindset.
Reflective spot metering allows us to tie a very specific point in the scene, typically the shadow point for a landscaper, to a very specific point on the the film curve. Measuring that specific point that one wants to tie to the film is mentally a strong connection, it feels emotionally tangible. The reality is though that picking the point in the scene to measure is purely subjective and arbitrary.
Incident metering requires that we ask ourselves, when we look at a scene, do we want more or less shadow detail than normal?
Both approaches can get us to the same camera setting.
Good point regarding slide film Gary. I use only black and white film and hence I defer to those like you with the experience to comment on metering when using color film.
I completely agree that incident metering when taking landscapes can be difficult. Such difficulties arise, IMO, mainly when one tries to interpret the highlights. Small changes in meter placement can affect the SBR range significantly and result in a negative that can be either too low or too high in contrast. However, those who use VC paper have some means to rectify metering errors that are not off the charts. Of course, as we all know, shadow details must be on the negative for such to appear in the print. See below.
Mark-good comments. IMO, incident reading of shadow values are easily defined by simply placing the meter in the shadows where you want detail to be recorded. Subjects deeper in the shadows will of course show no detail. To obtain more detail further in the shadows? Simply move the meter deeper into the darker areas. The entire incident metering procedure has been well detailed by Phil Davis in his book.
I also agree that one should feel comfortable using both reflected and incident meter readings. As you both you and Mark infer, there are situation where one method might be "better" than the other.
Yes Andreas...testing materials is the "hard stuff", but the results make the rest of the process easier. However, testing for BTZS methods is rather easily and inexpensively done. This is not the forum to comment on film testing services. Feel free to PM me if you need more details.
Actually Elliot, two things, pegging to and understanding the highlights is quite easy with an incident meter and exposure placement changes do not change the SBR.
When we use an incident meter pointed directly at the light source, we get a reading that protects the highlights nicely. This is a direct objective measurement of the real luminance involved, it can be expressed as a real number that our industrial photographic process equation understands.
To put this into to practical terms, think front lit subject matter mid afternoon on a beautiful sunny day, the perfect "Sunny 16" situation. The utility of this measurement is well proven. Given a tested E.I. is being used, there is no question about whether or not the incident meter pointed at the light source in that situation will provide good technical placement, it will be right period. The only wild card here is if the photographer has calibrated him or herself to the system and any artistic bias.
Life is rarely that simple though. If our subject is in that situation but their face is turned away from the sun say 120 degrees we are faced with a problem. Most of their face is not not lit by the sun directly but some is. Most of the face is now lit by open sky and the reflections off the landscape. In this situation we get a second reading with the meter pointed along that 120 degree line back toward the camera. That reading alone will get us a perfect exposure for the subject as lit by the open sky and reflections.
At this point we have the info we need to decide on how to deal with both light sources. A simple averaging of these two readings is simple duplexing. It is a compromise. It does its best to protect detail from both lighting situations. It allows a little shadow and a little highlight detail to fall outside the straight print range. This is exceptionally useful for slide shooting. It also provides the info needed to make decisions about contrast, maybe we choose Astia or Provia here instead of Velvia to adjust to the SBR we decide we want. With negatives we can decide on development choices because we have the info needed to know if contrast is "normal" for us or not.
Onward, SBR is a chosen range that we pick out of the scene. It isn't effected by anything else.
With negatives as long as we get our whole chosen SBR somewhere between toe and shoulder on film, the exact placement doesn't matter to the contrast calculation. Sure an underexposure where we let things fall off the toe or overexposure where highlights fall off the shoulder are a problem but if we get in the middle there is no loss nor gain of SBR. Anything on film but outside our chosen SBR has to be accessed by using burn or dodge or changes in paper grade.
Our challenge, when our SBR is in the middle, is matching our chosen SBR to our paper.
Thanks Elliot for your offer I may get back on that. I have been using BTZS for a few years and had some issues with it.
I have not used slide film or colour film for over ten years now (unless I take photos of my cat). Isn’t it more important to orientate ones exposure a little more to the lighting using slide film? Letting more fall off in the shadows.
With negative film pointing the dome directly to the light source will give us a high SBR and if we develop accordingly we do get rather soft negatives.
I think it is important to keep the contrast up a bit and do the rest in the darkroom. At least in a high contrast scene.
Personally I prefer the incident light meter since I believe (for me) it is easier to get good usable negatives where I get the information on the film.
Still there should be a easy and simple rule how to use a light meter. There are enough people who take wonderful photographs and do not care about testing. Often I get asked how to measure a scene and I never find a simple way to explain it.
The above article does help.
Thoughtful reply, and thanks.
We will simply have to differ a bit in our ideas about the SBR being unaffected by the metering of the highlights. Perhaps I am not completely understanding your position (pun not entirely intended!).
Note that I most often follow the BTZS methods in which the SBR value is obtained by high EV minus low EV plus five. Once again, this forum is certainly not the best place for a complete discussion of the pros and cons of the BTZS methodology which knowledge can be best obtained by reading some articles at BTZS.org and reading Mr. Davis's interesting book. Now might be a good time to remind folks that "BTZS" does NOT stand for "Better than the Zone System" as some have mistakenly believed. Indeed," Beyond the Zone System" is the correct translation!
To extend your comments about metering: If you've a moment, simply walk into the light and meter a shadow point in our scene. Then point the dome of the meter at the make believe camera position and slowly rotate the dome upwards directly towards the sun. The EV reading will increase as the dome is pointed upwards; the SBR will increase ( high EV minus low EV etc), the developing time based upon testing meant to keep the film exposure on the "straight line" of the curve will decrease and the highlights are-as you pointed out-protected. Now point the dome directly at the make believe camera position so that the sun light strikes only the top or part of the dome rather than the "complete" circumference of the dome. The highlight EV value will decrease, the SBR will decrease, the developing time will increase, etc.. Note for emphasis that I am alluding to BTZS methodology. We entirely agree that one can manipulate the SBR for creative purposes-roughly analogous as zone shooters do when they "place and values fall". Of course, as we also agree, matching the SBR both to our creative vision and to the combination of paper and paper developer that we use, provides the creative control that analog black and white photographers seek.
Incident metering is another tool, and one that some find extremely useful and even easy to use. However, like every tool, such metering will have to be applied correctly and modified by experience, results, and creative wishes. So, we agree in what is important: Making images that reflect one's intent and vision.
Stay well Mark.
Thanks again for stimulating the discussion.
No argument at all Andreas. BTZS adherents certainly do control the contrast of the negative by the placement of the highlights. Experience with such placement-when used with one's particular materials-allows one to affect the contrast of the resultant print.
My last visit to Berlin was about 6-7 years ago. The cranes were all over the skyline, and Museum Island was being resurrected. The Parthenon....
Yeah at least what you saw back then is finished although they are still building something new next to the Parthenon, with have to check how far they are there. Haven’t been down there for a few months.
But have you heard about the Airport. About two years behind schedule and it proberly going to take another two years. Embarrassing!!
Yes, I had heard recently about the construction at the Berlinairport. Then again, in my adopted home town of Hamburg construction at the new Harbor City is also encountering delays and massive cost over runs.
Incident metering the shadows(placement is critical) and decreasing the exposure by a stop, works for me for roll film. But then testing is required to establish E.I and development times for seven stop development(personal choice).
Thanks Mark Barendt and BTZS.
Elliot I fully agree that where and how the head is oriented for each reading does make a distinct difference to the SBR calculation.
Your reference to BTZS does bring up a good point, when we talk about and try to mentor others our frame of reference is very important.
In my frame of reference and practice, when duplexing or measuring contrast I always point the incident meter directly at the light source for the highlight measurement then I measure parallel to the camera axis. I use these two because the highlights and the mid-tones are of most importance to me personally. Typically I only feather the meters head to bias my exposure when using a single dome out reading.
For others, shadows and mid-tones, or shadows and highlights, may be more important to peg, there's no rule against picking different lines and places to measure, or to feathering the meter head one way or another, those are very reasonable artistic or technical choices.