Exposure calculation craziness

[Outdoorsman]

Okay, this might get complicated, so be warned...
All right- we all know that very dark or light subjects can fool our in-camera meters. A bright sunny day will cause the meter to underexpose in order to gain a correct exposure. But we know that to get some detail back into the shadows, we must add some exposure to compensate for this. Hence the need for an exposure compensation function on our cameras. This also goes the opposite way. A very dark subject will cause the meter to overexpose, and so we might underexpose to correct this. Here comes the question, and I'll put it in realistic terms.
I need a shot of a cormorant. These are black(ish) duck-like sea birds. So naturally I would underexpose them to get some detail on their feathers, going along with the notion that the meter is overexposing to compensate for the dark subject. So if I set the camera to the exposure compensation needed to get the birds exposed properly, then how should I approach the metering of the rest of the scene? I could simply go for an ISO change (I'm shooting film here) which would mean going from 100 to say, 160 or 200, to be sure that there is consistency in the metering, and more importantly, to not have to look at the little meter mark in the viewfinder and think, "Well, I'm underexposing the whole scene, so now the standard exposure for this subject is _____ (enter shutter/f-stop here). Well, I want to overexpose this to brighten up the birds a bit, so I should now adjust _______ (enter the answer to my question here!!!).
This has befuddled me so utterly for quite a while now. I use exposure compensation to correctly meter a scene in many situations. So I consider the corrected exposure "standard" for the particular scene. But when I want to then over- or underexpose that metering, I tend to trip up on what the right move to make is. Invariably I get it right, or at least close, but without a camera that saves exposure data, I can't know what settings to remenber. And I really don't have time to write it all down, frame-by-frame. I simply don't have the time. Basically I'm asking, "If I'm underexposing a black bird to correct for the fooled meter, how do I then overexpose that metering of the scene?" I think the answer might be right in front of me, but I can't figure it out.
I know this has gotten really long and I apologize, but I'm just not getting it. Does anyone have any advice here? Am I making any sense?

[ner]

I think your question is: "if I deviate from the settings recommended by the meter to secure a low value (e.g., black), how do I simultaneously assure that high values in the scene will be rendered appropriately (e.g., that white will appear as white, not grey)"? The answer, in oversimplified terms, is: expose so that your important dark values fall where you want them to and control your important high values (i.e., contract or expand contrast) through corresponding changes in development. There will be situations where you have to compromise to preserve important values on one end or both ends of the scale. Voila.

NER
http://normanrileyphotography.com/

[another view]

They're black all right! They have enough oil on their feathers that a little sunlight will make some highlights and give you some detail - this makes life a lot easier. There are a few ways to approach this - I assume you're using slide film and this is the worst case scenario (neg film has more latitude, just use a good lab for the best prints).

If using a center weighted or matrix meter, the first thing to consider is how big the bird is in relation to the frame, and what the background is. If the bird is small in the frame and your background is a backlit lake, you have the opposite problem! I have a shot of a cormorant from Acadia when I was there a few years ago - the bird is standing and most of the height of the frame. It's a horizontal shot with rocks and a front-lit lake in the background. It didn't require any compensation in the exposure because the lake and rocks were a neutral tone and the bird was relatively small in the frame. If it's a big portion of the frame (tight shot) then compensation becomes much more of an issue. Put a small bird (small in the composition) against a black background and you have the same problem - think about what information the camera's meter is working with.

The direction of the light will have an effect (in changing the light on the background too) so you might save the bird and lose the background. Bracketing wouldn't be a bad idea...

Another thing to do would be to use a spot meter and take a few readings. In my shot above, I'd look at the rocks that the bird was on and (knowing the shot) guess they should be at "0" to +1/2. Then check the bird itself which should be about 1-1/2 stops less (remember front lit, some detail), check the sky (might be a little sky in it, can't remember!) to make sure it's not blown out. Having all that info, I (theoretically) shouldn't have to bracket and will know exactly what the slide will look like. But I'd still bracket a little just to be sure.

The advantage of using the spot meter - which is kind of a modified zone system technique - is that you don't have to guess how the meter will interpret the scene, you make the decisions. I do use matrix and centerweighted metering quite a bit - but in tricky situations a spot meter is very useful.

[Outdoorsman]

Holy cow, the responses you guys gave me were great! So much useful information. I put it to good use, I think- after traversing a narrow spit of boulders (no land underneath, just rocks) in a driving rain and dealing with all sorts of horrible shooting conditions, I came back with a few rolls of cormorants. I'm not done, but I'm getting closer. Here's two images. The aerial one is the TerraServer view of the spit. The red dots are about 1/4 mile apart. The left dot indicates where I was shooting. The right dot is where the land ends and the rocks begin. It's about another 1/4 mile from my car. The yellow X is under water during high tide, so you have to time your visit just right.
The cormorant pic I just burned off the scanner real quick- and I'm beginning to think my scanner is a lemon. It just won't give me any kind of usable results from slides or filmstrips. I shot the bird on Fuji Super HQ 100 print film, since It was all I had left after I ran out of Provia. The colors are horrid, but at least you can tell what it is.
I overexposed by 1 stop and then bracketed to 1/2 stop; this shot was the 1.5-stop exposure. The weather and tides won't cooperate until the end of the week, so by then I should have some nice sunlight to work with

[paulnj]

BLACK on a middle tone BG.... +.3ev- 1/2ev WITH CENTER WEIGHTED METERING

BLACK on a LIGHT BG..... +1-1.3EV ..IN CENTER WEIGHED METERING

nothing more to it(IF you shoot a canon! but some under expose a 3rd from the start)

[Outdoorsman]

BLACK on a middle tone BG.... +.3ev- 1/2ev WITH CENTER WEIGHTED METERING

BLACK on a LIGHT BG..... +1-1.3EV ..IN CENTER WEIGHED METERING

nothing more to it(IF you shoot a canon! but some under expose a 3rd from the start)

Sure, easy for you to say- you're the bird guy!
Actually, I spot-metered the shots. I was more interested in getting detail in the feathers than getting a correctly exposed sky. This was shot at f/8 with my 70-300 set at 300. I won't even discuss the shutter speed- so slow I could cry! On a nasty cloudy day, did I mention? So I'd rather have a blown-out sky than an unreadable bird. I am not liking the 10% spot of my Elan- my old 650 is like 5 or 6 percent. Much easier to get a precise reading. Anyway... today I'm going a half mile north of the above location to shoot surfers. It's going to be foggy and dim and I won't be able to use AF, and I'll have to really add some exposure, means slow shutter for sports, wah, wah, poor me. If it wasn't for the weather, this place would be perfect!!!
So why the choice of center-weighted metering? I know this is suposed to be the "pro" method of metering, and my camera will do it, but is it better? I really don't see an exposure difference between the center-weighted metered pics from my old full-manual Vivitar and matrix-metered ones from my brand-new Canon.

[paulnj]

WELL.... CW metering takes into account MOSTLY the main subject. but yes, spotmetering on a evenly dark colored subject SHOULD render the same image as center weighted ;)

center weighted metering on changing subjects that are large in the frame is more accurate than spotmetering TO ME.

an example of what I mean.......

great blue heron, then a heermans gull, sunbather , DC cormorant, osprey, harbor seal, white pelican.....

no need to spotmeter and recompose TOO, just set the comp to wht you feel is right(or bracket) and go ;)

I shoot mostly evalutive and comp though

BTW your subject is the bird..... the grey sky will be 2 stops over exposed when you expose a BLACK subject corectly and dare I tell you a white BG would be 4 stops over ;o

from white to black is 4.83 stops

[ner]

"BTW your subject is the bird..... the grey sky will be 2 stops over exposed when you expose a BLACK subject corectly and dare I tell you a white BG would be 4 stops over ;o"

Assuming that were true, the "problem" could, within limits, be corrected through development control, namely contraction or "minus development." Setting those adjustments aside, whether a background appears grey or white given a fixed exposure for shadow detail, depends on the value of that backgound relative to the value of the shadow. In the original scenario, the photographer contemplated underexposing film to render dark values as such rather than grey. Under that circumstance, all higher values in the scene would fall lower on the tonal scale, not higher. Thus, a dark bird initially read at V but exposed for III, for example, would appear on III if the development were correct, while a background originally seen on IX (which is very nearly pure white) would drop to VII, which is a little darker than midway between pure white (X) and middle grey (V).

"from white to black is 4.83 stops"

This is not true in black and white analog work. 4.83 stops from dead black (Zone I) is just about Zone VI, i.e., about one stop above middle grey. Paper base white = Zone X.

[paulnj]

well, when Arthur Morris picks up a 8x10 and shoots a mountain from a roadside, then Ansel Adams can tell us about color work ;)

very informative indeed,but I do not shoot LF or B&W,so I see not reason to master the ZONE SYSTEM

let me rephase my quick comment.

the value of reflectiveness is aproximately 4.83 stops between white and black(subjects) when shot against a middle tone BG. This is from Arthur Morris's book "the art of bird photography"

[ner]

I only said the statement was incorrect with regard to black and white film. From that perspective, I still can't agree with the clarified comment if it is supposed to mean that the difference between black an white is literally about 5 stops. However, it is true that pure black is about 5 stops less than middle grey, and that pure white is about 5 stops higher than middle grey. The difference between the two extremes is therefore about 10 stops with a continuous tone emulsion, not 5. I emphasize again that I am referring to black and white film. Color is way too complicated for me.

well, when Arthur Morris picks up a 8x10 and shoots a mountain from a roadside, then Ansel Adams can tell us about color work ;)

very informative indeed,but I do not shoot LF or B&W,so I see not reason to master the ZONE SYSTEM

let me rephase my quick comment.

the value of reflectiveness is aproximately 4.83 stops between white and black(subjects) when shot against a middle tone BG. This is from Arthur Morris's book "the art of bird photography"

[Sebastian]

I only said the statement was incorrect with regard to black and white film. From that perspective, I still can't agree with the clarified comment if it is supposed to mean that the difference between black an white is literally about 5 stops. However, it is true that pure black is about 5 stops less than middle grey, and that pure white is about 5 stops higher than middle grey. The difference between the two extremes is therefore about 10 stops with a continuous tone emulsion, not 5. I emphasize again that I am referring to black and white film. Color is way too complicated for me.

I think Paul is speaking in regards to color chromes as well as digital, both have similar lattitudes.

Print film, especially B&W, is completely different.

[ner]

Print film, especially B&W, is completely different.

So I've heard!

[another view]

It's not a color vs. black and white thing, it's a chrome (or digital sensor) vs. neg debate.

Chromes and digital sensors have about 5 stops from shadow to highlight. Anything outside of this is a blocked up shadow or burned out highlight, although you might get a little farther with chromes especially with the highlights.

I don't have anywhere near as much experience with negatives but there's a couple of stops or more on either side of the exposure. IOW, there's a lot more latitude so you can get more shadow and highlight detail in a high contrast situation. Or, if your exposure is off a stop either way you can still get a good print. Ansel said there's 10 zones in B&W so I'm not going to argue that...

[ner]

I'll remember that the next time it occurs to me to try and be helpful.

It's not a color vs. black and white thing, it's a chrome (or digital sensor) vs. neg debate.

Chromes and digital sensors have about 5 stops from shadow to highlight. Anything outside of this is a blocked up shadow or burned out highlight, although you might get a little farther with chromes especially with the highlights.

I don't have anywhere near as much experience with negatives but there's a couple of stops or more on either side of the exposure. IOW, there's a lot more latitude so you can get more shadow and highlight detail in a high contrast situation. Or, if your exposure is off a stop either way you can still get a good print. Ansel said there's 10 zones in B&W so I'm not going to argue that...

[Outdoorsman]

All right, not to drag out what seems to have become a very technical discussion, but I have absolutely no idea what this zone stuff is about. I've never heard of it, and I am not at all understanding it. It sounds extremely important, and I'd love to learn it, but is it something that can be briefly described in idiot terms for me? Or should I go pick up a book on it?
And about this # of stops between black and white when compared to a middle gray, I'm getting really confused. How do I get my tiny brain around this and then apply it in the field? I've learned how to meter subjects by trial and error using the camera functions available to me, not by any system I've learned. It would have been nice all this time (and $rolls$ of film) to have a guide or framework or system to apply that would get me better results than trial and error. I'm pretty consistent now, and getting slowly better, but I still have nagging doubts every time I shoot.

[ner]

The zone system, developed in 1940 by Ansel Adams and Fred Archer, is a method of control in black and white work that enables the photographer to consistently produce images that express his or her visualization. It is, as Adams once wrote, regarded by many as "a short-cut to technical proficiency." Successful application relies on an understanding of how both exposure and development influence negative densities. Despite all the hoopla, the zone system is easier to understand and use than some may suggest. Entire books have been written on the subject, including several that discuss its applications in roll film work. You would do well to consult one of those if you're interested in learning more about this approach to photography.

[paulnj]

So , what book/ooks would you suggest to us?

One can NEVER know too much about photography, or anything for that matter

[ner]

"The Negative" by A. Adams provides a good general overview of the subject, as well as other information making that book a good investment for photographers at all levels of skill and experience. If you go to Google or any other major search engine and type in "zone system," you'll be directed to many sources, including on-line articles about the system's application to roll film, that do a very good job of introducing and explaining the zone system.