Of course, you are correct. I was a bit distracted for a moment... :) You don't open up from an incident shadow reading to "place" a shadow; that's what you do with a reflected-light meter. Thanks for the correction; I wouldn't want to mislead anyone.
What I wanted to point out is, if you just take an incident reading from the shadows, you will certainly get enough shadow detail. The question is: do you really want it? Many times you want darker areas in the shadows to be completely featureless, and the incident reading wants to place them higher. For me, this is "overexposure," which with LF B&W may not make much of a difference, but may be a consideration with smaller formats.
I can envision a scene with deep shadows that contain gray objects, maybe a darker brown or something, that would fall on or above Zone III with the incident shadow reading, but which I would really want to be rendered black in the final print, since they are the darkest areas in the scene.
I guess that's the real drawback of incident metering in my opinion, the inability to use the meter reading as a visualization tool. I use a spot meter primarily, and, despite all the inaccuracies inherent in the whole system, can fairly well determine where print values will be. Often I depart from "correct" exposure for expressive reasons. I just can't do that easily with an incident meter.
Also, one poster suggested taking an incident reading from the shaded and lit portions of the scene and averaging these. This would also be less than optimum, and, depending on the scene, could result in either over- or underexposure.
If I were using an incident meter, I would be using BTZS meter techniques for sure.
it's a great book from s great educator. it taught me all i needed to know.
When using colour negative film you would place the incident light meter in the shadows and obtain a correct rendition of the shadows. Due to the very large exposure latitude of negative film you would very likely get most highlights properly in any case. Just meter for the shadows when using colour negatives. Set your light meter to the nominal film speed, and meter for the shadows, that is.
When using B&W roll film, do as above with colour negative film.
When using slide film in a high-contrast situation where the highlights must (obviously) not block or be overexposed and the shadow detail is important as well, you can either use the incident light meter in both lighting situations and see how far "apart" they are to try to estimate what the final image will look like. You will meter in any case for the highlights as indicated by the instrument, the second reading will only give you and idea of where the shadows will block. In these situations a negative film would typically perform better due to its much broader exposure latitude.
As an alternative in the above case (slide film, high contrast) you would use a spot reflected light meter, "placing" the highest light on top of the characteristic curve of your slide film (let's say 2.5 EV above middle grey) and check, with the instrument, what happens to the shadow areas and where will they block.
This is not so easy as it sounds though because, being a reflected light meter, for each measure you have to notice if the reflectivity of the subject, on the measured spot, is way apart from "middle grey".
So I pointed out that it's not spot metering where you stop down two stops to place the Zone V on Zone III.
But it's looking now like Doremus was right in the first place, and with a rephrased reason it makes sense!
You really do close down two stops from the incident shadow reading.
Not to shift a metered Zone V to a placed Zone III but instead the reason you do it is to drive the tones down in the shady part of the picture.
[QUOTE=Doremus Scudder;1317838]agree so farQuote:
You don't open up from an incident shadow reading to "place" a shadow
huh? you are saying to open up with a refected light meter to place a shadow? I presume that you want the shadow to be darker i.e., to "place" it lower on the scale of zones, well then, stop down from the metered value, not open up, reflective or incident.Quote:
; that's what you do with a reflected-light meter
Doremus only clarified the thought process, not the direction.
In fact ... you do close down, all three of us can easily agree.
It accomplishes the same outcome.
At first I disagreed to even close down. And technically if you leave the shadow incident reading as-is it will give plenty of shadow detail.
But even Minor White closed down from palm reading in shadow (normally VI) to place palm reading in shadow on Zone IV. Palm readings are essentially incident readings. So since Minor White said it is the right thing to close down (an effectively incident shadow reading) two stops... I'll listen. I typically take what he says as a benchmark to check my thinking. If I disagree I had better have a good reason. In this case I think he is right.
And I think Doremus was right at the very first post. Close down two stops.
Oops, time for some clarification. I was certainly unclear, and maybe going the wrong direction on my mental meter it seems...
So, to summarize:
If I spot meter, I read a shadow and then place it in Zone III by stopping down two stops from the indicated reading. If I use an averaging meter to read the same shadow, e.g., by getting very close to the subject I'm metering so that other luminance values won't affect the reading, then I do the same. My spot meters, however, have Zone dials/stickers on them, so I no longer think of metering and placing my Zone III (or VI) value as "stopping down."
However, if I use an averaging reflected light meter and meter the entire scene, and then assume this average is middle gray, I use the indicated reading and hope that the average really is middle gray (whatever that means to my meter, Bill and Steve :whistling: ) and that the shadows I want detail in are really two stops down from that average and fall nicely in Zone III. If I use a gray card, I do the same. This method works well in all but contrasty situations, but can give more exposure than needed in flat light, especially if expansions are being applied.
If I take an incident reading in the shadows and use the indicated settings, I'll get good shadow detail, but may have more exposure than really needed. No problem for most negative materials, but this could lead to overexposure and subsequent highlight blocking in really contrasty situations and/or more grain with small film.
If I take an incident reading in the light that is illuminating the non-shadowed areas of my scene, I'll have a great reading for slide film (as mentioned above), but will lose shadows in contrasty situations, which is not optimum for negative materials. Often this is where advice is given to open up some from the meter reading, either by an arbitrary stop or so, or by taking a shadow reading and averaging. Both of these latter likely lead to less-than-ideal exposure in more extreme situations.
What Minor White seems to be doing in your example Bill is "placing" his shadowed palm in Zone IV, which would put his sunlit palm in Zone VI if there was a two-stop difference in the illumination between lighted and shaded areas of the scene. This is pretty common and, as mentioned above, one often hears "take a reading in the light and open up two stops for subjects with lit and shaded areas when one just takes an incident reading in the light. This could be the source of my open-two-stops from the meter reading unclearness. Again, I think this works for many averagely-lit scenes, but not for extreme situations.
There, I think I've got it in a clearer form now. Sorry for the confusion.
I'd better correct my fuzzy explanation above before I confuse anyone else (or myself) further. :)
My assessment of what Minor White was doing above was a bit unclear. He is obviously placing his shaded palm in Zone VI. This is, as Bill points out, similar to taking an incident reading in the shadow and closing two stops. White seems to have used this method to hold good shadow detail in the shaded areas. The rendering of subjects in the shadows are two-stops "underexposed" as compared to a "correct" exposure for subjects in that light alone, which ensures that middle gray shaded subjects end up in Zone III, i.e., as detailed blacks. A pretty safe shadow placement.
This results in a lit reading of his palm ending up in Zone VI (the "correct" Zone) only if there is only a two-stop difference between the illumination in lit and shaded areas. This is common, but in many outdoor scenes the difference in illumination between lit areas and open shade is greater than this, sometimes three or even four stops.
Variations of the "Sunny-16 Rule" recommend opening up from two to four stops for subjects in open shade (one reason I like to use a meter... there seems to be some questions about what common outdoor lighting ratios are). White's placed palm would fall in Zone VIII if the lit area were 4 stops brighter than the shaded area, or in Zone VII if the difference were three stops. This would result in overexposure of the lit subjects unless development was appropriately reduced from "Normal." I assume White took some readings of the lit area and adjusted his development accordingly as well.
In a situation where the lighting difference between shaded and lit areas is four stops (incident reading), opening two stops from the lit reading, or closing two stops from a reading taken in the light will result in the same exposure.
On a bright sunny day, with important subjects both lit and shaded, taking a reading of the lit area, or an incident reading of the light, or a palm reading in the light will usually result in underexposure, unless the shadows are pretty bright. I've heard the admonition to open up a couple of stops from such a reading in a bright contrasty situation (and reduce development accordingly), which is the source of my mistake a few posts earlier.
At any rate, I use spot-metering techniques for almost everything anymore, and haven't used an incident meter in years.
I'll quit now... I'm not helping the OP anymore.