Average Spot Metering Question

[IanBarber]

My usual method is to meter the shadows, meter the highlights, workout the brightness range and then adjust development if the brightness range is above 5 stops.

For example, if the brightness range is 6 stops then I do N-1 development.

Question:
If I was to meter the shadows, meter the highlights and then make an exposure at the average of the two, what is actually happening. What I mean is, how will the tones be distributed.

[Alan9940]

Theoretically, the average meter reading value would be Zone V middle gray. All other luminance values would distribute along the curve. When shooting transparency film, that’s my basic metering technique; though I will scan the scene to determine the EV differences from the average, then adjust my exposure accordingly, if needed.

[Luis-F-S]

Meter the palm of your hand. Open up one stop. Set it in the lens and take the picture. Of course some would rather have discussions about meter readings than actually take pictures

[IanBarber]

Theoretically, the average meter reading value would be Zone V middle gray. All other luminance values would distribute along the curve. When shooting transparency film, that’s my basic metering technique; though I will scan the scene to determine the EV differences from the average, then adjust my exposure accordingly, if needed.

So if the brightest area is 2 stops brighter than the average and contains detail you want to preserve, you would then open up your exposure by 2 stops.
Have I understood you correctly Alan

[consummate_fritterer]

I've never 'averaged' meter readings. I metered shadows and exposed for them. I metered highlights and midtones and decided on proper development for those. If the final print wasn't expected to have a long tonal range then I usually gave a little extra exposure to pull the low tones off the toe.

[Peter Collins]

I think that, with the info that the OP presented, there is not an exact answer. Which shadow? How deep? Which highlight? How bright? The range of luminances might be 3 stops, or might be 6, etc.

[Bruce Watson]

If I was to meter the shadows, meter the highlights and then make an exposure at the average of the two, what is actually happening. What I mean is, how will the tones be distributed.

Easy enough to find out -- this is what digicams do. That is, this is what your average smart phone does.

That said, one of the prime reasons to do LF in the first place, at least for me, is control. If you aren't trying to get the most out of your film (nailing the exposure, nailing the development), then why are you going through all the time, expense, and frustration of LF?

[IanBarber]

I think that, with the info that the OP presented, there is not an exact answer. Which shadow? How deep? Which highlight? How bright? The range of luminances might be 3 stops, or might be 6, etc.

Sorry, I ought to have mentioned some readings.

Shadows = EV 10.5 (bunch of trees)
Highlights = EV 18 ( sky with wispy clouds)

[Alan9940]

So if the brightest area is 2 stops brighter than the average and contains detail you want to preserve, you would then open up your exposure by 2 stops.
Have I understood you correctly Alan

Well...my comments are, of course, based on my Sekonic L-558. Also, I should mention that I use a calibrated Pentax Digital Spot meter when shooting B&W. The Sekonic I use strictly for the little bit of color work that I do.

I meter a shadow area where I want to preserve detail, and then store that reading. I meter a highlight (high value) area where I wish to preserve detail, and then store that reading. Then, I press the "Avg" button. I know that this meter will give me good high values up to about +2.5 stops over the average, and good shadows down to about -2.5 stops under the average. This is about a 5 stop range which is pretty much the limit of the Velvia 50 or Provia 100 that I shoot. Before I expose any film, I will hold in the metering button and scan the scene watching the EV difference from the average. If I don't find any other highlight and/or shadow area that falls beyond that -2.5 to +2.5 range, then I twirl the wheel to obtain the aperture I wish to shoot at, set the exposure accordingly, and expose. If I find an area outside the aforementioned range--lets say I scan across a shadow area that reads -3.0 EV that I care about (who knows why I didn't see that area in the first place!)--then I adjust my average reading accordingly and expose. This is all way more difficult to write about than it is to do...

[Alan9940]

Sorry, I ought to have mentioned some readings.

Shadows = EV 10.5 (bunch of trees)
Highlights = EV 18 ( sky with wispy clouds)

I was going to mention in my post above about scenes that are beyond normal SBR (subject brightness range.) EV 18 clouds?! Wow!! I've never measured a cloud value beyond EV 17 and I live in the desert!! :D I guess when y'all get clouds in the UK them frickin things are BRIGHT!! Are you sure your meter is accurate?

Anyway, based on these readings you're looking at a tremendous brightness range. Forget holding all that with transparency film. Color neg might be OK; those with experience shooting color neg might weigh in. For B&W, if you placed the 10.5 on Zone III or IV, then you would definitely need minus development if using a standard film developer. Using pyro and some sort of compensating development technique, you might be OK as it stands.

[Pere Casals]

how will the tones be distributed.

Ian, this is quite easy... once you select an exposure (using any method...) you know how many stops will we under or overexposed any spot in the image.

If you have 6 stops range you first have to decide at what zone you are to place your shadows, it can be Z-III or Z-IV depending on the detail you want to conserve in the shadows. Let's say that you place the shadows in Z-III, then your highlights will be in Z-VIII or in Z-IX, depending on how you calculate your 6 stops range.

You shoud always expose enough to preserve your shadows, then it can happen that you burn your highlights, Z-IX can be too much... but you solve that with development !!!! So with a high range scene you expose to preserve the shadows and then you develop less to prevent burning the highlights. Well, we have the highlights in the Z-IX, we may want it in Z-VII, so 9-7 = 2, an N-2 development plaves your highlights in Z-VII !!!! Solved !

Note that N-2 development does not modify much the shadows, while it limits the excessive density in the highlights.

So this is the classic recipe for a high dynamic range: expose to have your shadows in Z3 or 4, then develop less to place the highlights in Z7 or 8. Using Z3/4 or 7/8 depends on the film you use an on the detail what you want to obtain.

This is for negative film... slides are another animal.

[IanBarber]

I was going to mention in my post above about scenes that are beyond normal SBR (subject brightness range.) EV 18 clouds?! Wow!! I've never measured a cloud value beyond EV 17 and I live in the desert!! I guess when y'all get clouds in the UK them frickin things are BRIGHT!! Are you sure your meter is accurate?

It was hovering from 17 to 18. I am wondering if I was also getting flare because the sun was just outside the meters viewing area

[IanBarber]

Let's say that you place the shadows in Z-III, then your highlights will be in Z-VIII or in Z-IX, depending on how you calculate your 6 stops range.

Is there no set method for this. What I mean is, do you include zone 3 and count from there or do you start counting from zone 4. Doing the latter will give you N-1 whereas the other one would give you N development, if you know what I mean

[interneg]

I was going to mention in my post above about scenes that are beyond normal SBR (subject brightness range.) EV 18 clouds?! Wow!! I've never measured a cloud value beyond EV 17 and I live in the desert!! :D I guess when y'all get clouds in the UK them frickin things are BRIGHT!! Are you sure your meter is accurate?

Anyway, based on these readings you're looking at a tremendous brightness range. Forget holding all that with transparency film. Color neg might be OK; those with experience shooting color neg might weigh in. For B&W, if you placed the 10.5 on Zone III or IV, then you would definitely need minus development if using a standard film developer. Using pyro and some sort of compensating development technique, you might be OK as it stands.

I suspect that it's not 'actual EV' which is correct for ISO 100, but has been shifted two stops for an ISO 400 film. In other words, it's an EV of 16 in absolute terms, but the meter reads out 18 as it's been set to ISO 400 - my Minolta meter does this & it's quite annoying!

[IanBarber]

I suspect that it's not 'actual EV' which is correct for ISO 100, but has been shifted two stops for an ISO 400 film. In other words, it's an EV of 16 in absolute terms, but the meter reads out 18 as it's been set to ISO 400 - my Minolta meter does this & it's quite annoying!

My meter is a Sekonic L758. Should the EV value not reflect what ISO you have the meter set to ?

[Leigh]

What I mean is, do you include zone 3 and count from there or do you start counting from zone 4.
Hi Ian,

If your shadows meter to Zone V, and your highlights to Zone VI, your SBR is 1 stop.

- Leigh

[IanBarber]

Hi Ian,

If your shadows meter to Zone V, and your highlights to Zone VI, your SBR is 1 stop.

- Leigh

Thanks

[Drew Wiley]

The whole point of spot metering is to know exactly what specific scene values are, so you can give threshold shadow values correct placement in relation to highlights and degree of development. Averaging has nothing to do with it. What "zone" the shadows should fall on differs relative to the specific film, contrast range involved, and your esthetic goal with the negative. So no, there is no set method, and never will be. But it's easier to learn staying with one film and developer to begin with, to minimize the variables.

[Alan9940]

I suspect that it's not 'actual EV' which is correct for ISO 100, but has been shifted two stops for an ISO 400 film. In other words, it's an EV of 16 in absolute terms, but the meter reads out 18 as it's been set to ISO 400 - my Minolta meter does this & it's quite annoying!

I can tell you for fact that the Pentax Digital Spot meter that I've used for many a year reads out EV values based on the luminance of the object the spot is on...period. I'm pretty sure the Sekonic works the same way, but now that you've brought it up I'm definitely going to test it.

[Doremus Scudder]

Averaging the meter readings between high and low is what an averaging meter does. This works for scenes without excessive contrast for the most part as far as exposure is concerned. It has its shortcomings, which is why there are so many other (better) metering methods. Using your spot meter to, in essence, replicate what an averaging meter does defeats the whole reason for having such a meter, IM-HO.

The problem with basing your exposure on an average is that if the contrast range in the scene exceeds "normal," then the middle value you end up basing your exposure on is pretty high. This results in underexposing the low values and the corresponding loss of detail. In other words, you are no longer "exposing for the shadows," which is a better method than averaging.

To ensure you have the shadow detail you desire you have to base your exposure on an important shadow value, placing it so it has the amount of detail/separation you want. This determines exposure. Then you check the highlights to see where they will end up and make adjustments to development, choice of paper grade, filtration, etc. at that point.

Best,

Doremus

[IanBarber]

The problem with basing your exposure on an average is that if the contrast range in the scene exceeds "normal," then the middle value you end up basing your exposure on is pretty high. This results in underexposing the low values and the corresponding loss of detail. In other words, you are no longer "exposing for the shadows," which is a better method than averaging.

Right on queue Doremus, you were correct.

I did a test exposure yesterday using the average of 3 values as I have never tried this before.

I metered the deepest part of the trees, the middle value on the bridge and the brightest part of the sky and then hit the AV button and used that for the exposure.
You were correct, the image is under-exposed and the shadow areas have indeed lost detail.

179287

Apologies for allowing the cable release to enter the frame :D to busy trying to mentally see what the average would give me

[interneg]

I can tell you for fact that the Pentax Digital Spot meter that I've used for many a year reads out EV values based on the luminance of the object the spot is on...period. I'm pretty sure the Sekonic works the same way, but now that you've brought it up I'm definitely going to test it.

Yes - from recollection, the Pentax uses EV without shifting around with ISO changes. I think the ones that shift the EV numbers around call it 'LV' or something like that - not that it makes a big difference in actuality, other than confusing everyone!

[Heroique]

To ensure you have the shadow detail you desire you have to base your exposure on an important shadow value, placing it so it has the amount of detail/separation you want. This determines exposure. Then you check the highlights to see where they will end up and make adjustments to development, choice of paper grade, filtration, etc. at that point.

I thought a concrete example regarding "adjustments to development" might also be helpful…

This is a chilly shot near Mount Rainier where I aimed for detail on two ends of a very wide zone range, so I chose compensation development to rescue the highlights.

Here, the darkest tree-boughs were zone 3. The sunny dimpled snow was above zone 9.

I used dilute HC-110 – that is, 1+123 direct from concentrate (not stock), and tray-developed for 19 minutes in 68° F, w/ a little bit of agitation every few minutes. All the snow has texture in straight prints from my Omega D2-v.

179391

Tachi 4x5
Schneider 150/9 g-claron
Ilford FP4+ (in dilute HC-110) in trays
Epson 4990/Epson Scan

[Doremus Scudder]

I thought a concrete example regarding "adjustments to development" might also be helpful…

This is a chilly shot near Mount Rainier where I aimed for detail on two ends of a very wide zone range, so I chose compensation development to rescue the highlights.

Here, the darkest tree-boughs were zone 3. The sunny dimpled snow was above zone 9.

I used dilute HC-110 – that is, 1+123 direct from concentrate (not stock), and tray-developed for 19 minutes in 68° F, w/ a little bit of agitation every few minutes. All the snow has texture in straight prints from my Omega D2-v.

179391

Tachi 4x5
Schneider 150/9 g-claron
Ilford FP4+ (in dilute HC-110) in trays
Epson 4990/Epson Scan

Heroique,

Nice to see you posting! I haven't seen any posts from you in quite a long time and was wondering where you had gone. Glad to have your insightful comments here always.

Best,

Doremus

[Bruce Watson]

Heroique,

Nice to see you posting! I haven't seen any posts from you in quite a long time and was wondering where you had gone. Glad to have your insightful comments here always.

Best,

Doremus

+1.

[ic-racer]

My usual method is to meter the shadows, meter the highlights, workout the brightness range and then adjust development if the brightness range is above 5 stops.

For example, if the brightness range is 6 stops then I do N-1 development.

Question:
If I was to meter the shadows, meter the highlights and then make an exposure at the average of the two, what is actually happening. What I mean is, how will the tones be distributed.

The exposure for B&W negative material should be based on the shadow value, per the physics of the film sensitivity characteristics and international standards achieved through empiric research. Averaging that value with another will randomly alter your exposure. Maybe more exposure, maybe less. Why would you want that for your negatives.
If you are exposing transparency, then the situation is totally different. Averaging the values might help ensure the entire scene range fits on the film.

[Heroique]

Heroique,

Nice to see you posting! I haven't seen any posts from you in quite a long time and was wondering where you had gone. Glad to have your insightful comments here always.


+1.

Thanks for the kind words! It's a long story, but I do have a backlog of new landscape images to help illustrate it. Olympics and Cascades, of course. Look forward to catching up on the ever-helpful participation from both of you and so many others.

[Cor]

My simplistic approach with B&W: try to find a flare free spot in the shadows (so not close to a bright spot ) were I still want detail in my print, measure, call it Zone III, open up 2 stops, and let the highlights land wherever they want. I take care of these when printing (dodging/burning or changing the grade). Works reasonably well for me.

best,

Cor

[consummate_fritterer]

Cor, you mean you close down 2 stops (expose 2 EV less) than the meter reading of the Zone III area, right? :)

[Cor]

Cor, you mean you close down 2 stops (expose 2 EV less) than the meter reading of the Zone III area, right? :)

oops..you are correct off course, thanks for noticing..

best,

Cor

[Leigh]

If you want detail in the print, it must exist on the negative.
Therefore, you must expose for the shadows when shooting negative film (b&w or color).

An averaging meter assumes open shadows, like under a tree, not deep shadows like in a cave.

- Leigh

[Merg Ross]

Heroique,

Nice to see you posting! I haven't seen any posts from you in quite a long time and was wondering where you had gone. Glad to have your insightful comments here always.

Best,

Doremus

+2

I was thinking the same; welcome back.

[Randy]

This has always seemed to work for me:

Fred Picker Zone VI Newsletter #51 June 1987 p. 7

~~~~~~~~~~~~

It had finally dawned on me that when I made two exposures of a subject (to be absolutely sure I had enough exposure) the "overexposed" one always made the better print. Right? The best negative is the one that places all values as high as possible without blocking .

So I began to consistently place the high value on VIII, regardless of where I wanted that value to end up in the print.

I have made thousands of negatives that way and I am convinced that there is no faster, simpler, more foolproof way to get the best possible negative. I've been teaching this procedure at workshops for many years and hundreds of photographers have been delighted to find that it always works. I call my modification of the Zone system, "Maximum Printable Density (MPD) . " Note: The operative word is "printable," not "maximum!"

~~~~~~~~~~~~

[Doremus Scudder]

This has always seemed to work for me:

Fred Picker Zone VI Newsletter #51 June 1987 p. 7

~~~~~~~~~~~~

It had finally dawned on me that when I made two exposures of a subject (to be absolutely sure I had enough exposure) the "overexposed" one always made the better print. Right? The best negative is the one that places all values as high as possible without blocking .

So I began to consistently place the high value on VIII, regardless of where I wanted that value to end up in the print.

I have made thousands of negatives that way and I am convinced that there is no faster, simpler, more foolproof way to get the best possible negative. I've been teaching this procedure at workshops for many years and hundreds of photographers have been delighted to find that it always works. I call my modification of the Zone system, "Maximum Printable Density (MPD) . " Note: The operative word is "printable," not "maximum!"

~~~~~~~~~~~~

Fred Picker's method does indeed ensure adequate exposure for most situations, however at the expense of some increase in graininess in many cases. This may be of no import when the negative is large enough and/or the degree of enlargement is relatively small, but for smaller format film, this approach, due to the increased negative density, especially for lower contrast scenes, will give a grainier print.

Fred was cutting corners here to save time metering. He'd also all but given up on developing for different negative contrast ranges, using only N and N+1 1/2 if I remember correctly. Simplifying things may speed things up sometimes, but there's always a trade-off.

For "normal" scenes, placing the high value in Zone VIII keeps the shadows in Zone III, exactly where we want them. For less contrasty scenes, the shadows fall higher, e.g., in Zones IV, V, or even VI. This keeps all the values on the straight-line portion of the film's curve, so no lost detail, just more density than is really needed. (Still, we're not developing to achieve optimum density spread in the negative and relying on different paper grades to get the desired final print contrast if we just develop N. If, like Fred, you use N+1 1/2 here the result is basically an overexposed and overdeveloped negative).

The problem with this approach it that in very contrasty situations, you will lose shadow detail. If you have an 8 or 9-stop spread between the highest and lowest values in which you want detail, placing the high in Zone VIII will shove the shadows down to Zone I or 0. So, no detail in the shadows where we might want them. I have to develop at N-2 often enough that this approach won't work for me at all.

I believe it is better to base your exposure on a shadow value whenever possible, and when not, be aware of how the range of subject luminances can push the shadow exposure around and compensate when needed. A tweak to Fred's system would be to place high values in Zone IX or even X for very contrasty situations.

Best,

Doremus

[IanBarber]

For less contrasty scenes, the shadows fall higher, e.g., in Zones IV, V, or even VI. This keeps all the values on the straight-line portion of the film's curve, so no lost detail, just more density than is really needed.

Doremus,
Putting Fred's method to one side for a moment. With scenes which have a short brightness range maybe only 2 stops in some cases on a dull overcast rainy day, would you suggest placing the lowest value (you want) on zones 3 or 4 and extending the development time around 20% to spread the mid-tones further apart to give more separation.

[Drew Wiley]

I put Fred Picker's method aside a long time ago - in the trash can. One shoe simply does not fit all. You need to learn each kind of film according to its specific characteristics if you want optimal results. I'm just about to go thaw some roll film. Some of this has an extremely long relatively straight line (Efke 25), and some a horrible S-curve with a very short straight section (Pan F). Both can yield wonderful results IF you know what kind of lighting each excels at, and don't go around applying goofy shortcut advice. Then I have some other films in there too, constituting less radical extremes, like ACROS and both
Tmax's, but even these strongly differ. And when it comes to sheet film, esp 8x10, I simply can't afford to wing it. With a spotmeter, there's no need to.
Measure the shadows and ensure adequate exposure there, but don't leap up to a ZIII placement if you don't need to, or you're sacrificing something else,
either risking blowing out the highlights, or else being forced into reduced development and scrunching intervening tonality flat. With low contrast scenes,
you have the opposite problem, and benefit from either a higher-contrast film with a steeper curve or stronger development; but in such cases, you might be operating wholly between III to VII or even less range.

[Doremus Scudder]

Doremus,
Putting Fred's method to one side for a moment. With scenes which have a short brightness range maybe only 2 stops in some cases on a dull overcast rainy day, would you suggest placing the lowest value (you want) on zones 3 or 4 and extending the development time around 20% to spread the mid-tones further apart to give more separation.

I suggest (and practice) placing the important shadow or low value where I/you want it. This assumes you know what a metered value will look like on the neg/print. Then I check the other values and choose a development scheme that will give me the best negative to print from. For very low luminance-range scenes, like you describe, I'll choose an extended development time, usually coupled with planning to use a higher paper contrast grade/filter (I hate grain, so if N+2 or 3 is indicated, I'll often develop N+1 and use paper grade to get more print contrast).

However, although your concept of increasing development to "spread the tones out" is correct, I wouldn't recommend any arbitrary development-time increase, such as "20%," as you suggest. Test your system for expansion developments and find your own times. 20% might be just fine, it might be too much, etc., etc. I know what to expect exactly when I indicate N+1. and I know how much more contrast I can get from X paper with 170M on my enlarger.

That said, there's no harm in experimenting or making a "guesstimate" about how much extra development you need. Next time you have a situation like you describe, go ahead and give it 20% more development and see what happens, just don't expect the neg to be exactly right.

Best,

Doremus

[IanBarber]

That said, there's no harm in experimenting or making a "guesstimate" about how much extra development you need. Next time you have a situation like you describe, go ahead and give it 20% more development and see what happens, just don't expect the neg to be exactly right.

Best,

Doremus

Thank you Doremus, appreciate the reply

[Bruce Watson]

This has always seemed to work for me:

Fred Picker Zone VI Newsletter #51 June 1987 p. 7

~~~~~~~~~~~~

It had finally dawned on me that when I made two exposures of a subject (to be absolutely sure I had enough exposure) the "overexposed" one always made the better print. Right? The best negative is the one that places all values as high as possible without blocking .

So I began to consistently place the high value on VIII, regardless of where I wanted that value to end up in the print.

I have made thousands of negatives that way and I am convinced that there is no faster, simpler, more foolproof way to get the best possible negative. I've been teaching this procedure at workshops for many years and hundreds of photographers have been delighted to find that it always works. I call my modification of the Zone system, "Maximum Printable Density (MPD) . " Note: The operative word is "printable," not "maximum!"

~~~~~~~~~~~~

I remember this. And after running my own experiments I don't agree with it.

What Mr. Picker was advocating in the end was "expose for the highlights and let the shadows fall where they may". Which worked for him; he was only interested in highlights that "sang" for him. And his photographs of ice on small New England streams in winter are gorgeous, so it clearly worked for him.

Me? I actually like shadow detail. So for me I found what worked best was exactly the opposite: "expose for the shadows and let the highlights fall where they may". This works startlingly well for me and my drum scanning workflow.

Which goes to show that you should listen to what the teachers tell you, look at their work with a critical eye, and examine what you value, and look at your own work with a critical eye. Then, try everything. You'll find a workflow that works for you and lets you do the work that emphasises what you value.

But there's no substitute for doing the actual work. Reading about it is not enough. If you don't run your own experiments, you can't fully understand the results.

[Drew Wiley]

I like to have my cake and eat it too: excellent highlights and shadows, and good tonality in between to. Sometimes I might make an esthetic decision to
deliberately blank out one end or the other of the scale, but utilize the same metering skill and specific film knowledge to do that precisely. Even Picker's choice of paper didn't leave much room for shadow expansion. Brilliant Bromide dropped the shadows very very hard. It could be a wonderful paper for some
images, but was not highly versatile in my opinion. The DMax was luxurious when this paper was appropriate, and nothing since has been equal to it. it would probably be prohibitively expensive to make today. I do give Picker credit for some things. His images per se were nice but predictable. I liked his products
better, but otherwise ignored his advice. At that point in time, the Zone System had been beaten to death. And Picker certainly did not improve upon Adam's
time-tested adage to expose for the shadows and develop for the highlights.