Determing correct exposure

[Jay DeFehr]

Doremus,

Thank you for taking the time to share your methods and thoughts on this often bewildering subject. I agree when you say many misunderstand the Zone System, but I think you misunderstand the BTZS system in exactly the same way. BTZS testing generates a database of information related to the materials and processes used in testing. The incident metering technique advocated by (though not demanded. Spot metering can also be used) BTZS defines the exposure conditions, but makes no demands on the photographer to adhere to a literal interpretation of the scene, and no handheld computing device is required, by the way. It's important to keep in mind a photographer photographing an existing scene ( as opposed to a constructed one, in which the photographer controls the lighting) has only two controls available to him -- exposure and development -- whatever system, or lack thereof, might be employed. Because I know a scene contains a seven stop range of illumination from the darkest shadows to the brightest highlights does not obligate me to capture that entire range, but it provides a reliable point of departure. And let's be honest -- in practice, "zone placement" consists of nothing more than determining the range of illumination to capture on film, combined with appropriate development to translate that range to the printing process. One cannot alter the progression of tones in a scene by exposure and/or development controls -- lighter tones will always be lighter than darker tones, etc. The ZS keys this determination to a narrow range of tones, or a "zone", but does not, and cannot alter the fundamental principles of sensitometry.

What the ZS provides is a terminology that emphasizes interpretation, but that comes at the expense of a more holistic description. ZS practitioners talk about zone placements and plus or minus development, while BTZS users talk about Subject Brightness Ranges, negative Density Ranges, and paper Exposure Scales, but we should always keep in mind both camps are talking about sensitometry, in more or less abstract terms. I learned both systems, but mostly use my own shorthand version of sensitometry appropriate for the task at hand. I believe there is an appropriate degree of precision for any process, and exceeding that is wasted effort that can only distract from higher goals, assuming there are higher goals. So, while my squinting and guessing might seem lazy or sloppy to some, it's a well informed and carefully considered approach that allows me to work in a way that concentrates my creative attention where I think it's most needed and fruitful. Of course, this methodology isn't always appropriate for the task at hand, and so I adapt as needed.

In short, while I think a solid grasp of sensitometry is essential to creative photography, I don't think it's always necessary, or even best practice to apply the most precise methodology in every circumstance, but rather, the most appropriate one.

[Leigh]

Because I know a scene contains a seven stop range of illumination from the darkest shadows to the brightest highlights does not obligate me to capture that entire range...

Exactly. That expectation of rendering everything in the scene "visible" is a shortcoming of both ZS and BTZS.

The deafening din of the "shadow detail" mantra is an obvious example thereof.

Shadow detail is meaningful in some subjects, not in others, and distracting in still others.
Whether or not to emphasize it is an artistic decision that will differ for each subject and rendering.

I've been working on a project for a couple of years that's the perfect example of this... shooting locomotives.
Take an engine that's painted entirely flat black, top to bottom, with some pure white detailing, shot in midday sun.

There's a lot of interesting detail in the lower shadowed area, around the wheels, drive train, and support structure.
Holding full detail is possible with Acros, but probably not with any other film.

I advocate a simple incident meter protocol, coupled with an understanding of subject illumination and reflectivity.
I've used and refined this system for over 50 years, and it works for me.

In the case of the locomotives, I do take spot meter readings in the lower area to refine the exposures,
since Acros holds highlight detail quite well even with significant overexposure.
I don't think you can blow highlights in Acros even if you want to.

- Leigh

[Mark Barendt]

... I don't think it's always necessary, or even best practice to apply the most precise methodology in every circumstance, but rather, the most appropriate one.

I agree.

One of things that I think many people newer to photography don't get about the zone system and it's variants, is that minimizing exposure is one of the built in priorities.

Zoning is an advanced technique that has less room for error in practice, done well it doesn't matter, but if there is an inadvertent underexposure/mis-judgement of where that shadow really belongs, something important will probably be lost and the shot may be unusable.

I also think that many people believe there is one right way or one right placement. While that can be true for someone who is highly experienced, with a specific system and vision for the shot, and where all the pieces are tailored to produce a very specific result; for myself I find that there is a range of possible exposures that can produce very nice prints.

[Old-N-Feeble]

Exactly. That expectation of rendering everything in the scene "visible" is a shortcoming of both ZS and BTZS.<snip>

This is a common misunderstanding of the ZS. "Shadows" and "highlights", as defined by Adams, are only those that have meaningful impact on the final image. Those details are then placed, both by exposure and by development, according to one's vision of the final print. IMHO, Adams made this pretty clear. One can further enhance tonal scale and placement with selenium toning or other means.

[Ken Lee]

Jay - beautifully stated!

[Jay DeFehr]

Thanks, Ken. I'm sure some of the same thoughts are passing through your mind as you integrate BTZS into your own methodology.

[Chuck P.]

Incident metering can be used very directly to determine the exposure settings but it does not preclude "artistic" placement of an exposure.

Ok, I don't advocate any artistic advantages of spot metering versus incident metering (did not mean to imply there is), incident metering is just not for me when the 4x5 is out---the amount of control over the process, for me, is so much greater using a spot meter and the ZS.

[Old-N-Feeble]

^^^ I agree... except... I'll only be shooting very wide latitude color negative film so shadow placement is, for the most part, the only important thing. On the other hand, if tonal values are truly extreme then I'll meter for important shadow detail and place those at zone IV then take a second exposure of the important highlight detail and place at zone VIII and allow Photoshop to align and do a very simple HDR of two images... I don't like "extreme" HDR because it looks fake. I'll probably print monochrome as often as I do full color so... I may need to buy two printers because I'm too lazy to swap between color and monochrome all the time.

[Jay DeFehr]

--the amount of control over the process, for me, is so much greater using a spot meter and the ZS.

Are you sure you're not laboring under the tyranny of illusory precision (with apologies to Freudenberg)? Are you sure using a spot meter doesn't just feel more precise? In the end, we all arrive at a single exposure, however we calculate any number of meter readings. Do you think you would arrive at a different exposure by using a spot meter than you would by using an incident meter?

[Old-N-Feeble]

Jay... Using a spot meter is very much more precise... as exposure pertains to shadow detail. Modern films have so much latitude that overexposure doesn't much matter unless the dynamic range is off the charts.