Exposure compensation and zone system - am I thinking correctly?

tkamiya · Aug 27, 2010

I would just like to be certain I'm thinking this through clearly.

Let's say I'm shooting portraits. Just a regular portraits, nothing fancy. Assume it's lighted simply and the camera is set to SPOT metering. Also assume, my subject is a white skinned person.

If I meter on this person's face, the SPOT metering of the camera will place this person's face on ZONE 5. Because of the subject's tone, I wouldn't want this person's face to be in zone 5. I'd want the face to be in ZONE 4. I'd set camera's exposure compensation to be in +1.

Now, USING THIS SETUP, I meter this person's face, LOCK THE EXPOSURE, recompose, and shoot.

I'm not interested in knowing better ways of doing this, so please don't suggest. I am; however, interested in knowing if I am applying the correct logic, and using the zone system, metering system, and exposure compensation setting correctly.

Thanks in advance.

dehk · Aug 27, 2010

If you want it to be in Zone 4 it will be EV-1 Zone 6 will be EV+1

eddie · Aug 27, 2010

You'd want a white face to be placed in zone VI, not IV. Open up one stop from the zone V reading.

dehk · Aug 27, 2010

eddie said:
You'd want a white face to be placed in zone VI, not IV. Open up one stop from the zone V reading.

I was also thinking about saying that but maybe he's photographing something other than a white face. But yes, good point.

tkamiya · Aug 27, 2010

Yes, zone 6. I got that backwards. I'd want it one stop lighter than zone 5. Is my thinking correct otherwise?

My whole point is, since it is a portrait, I want the face to be correctly exposed. I'm thinking through how I'd compensate for the fact metering system will place it in zone 5.

eddie · Aug 27, 2010

We were asked to assume it was " a white skinned person".

eddie · Aug 27, 2010

Yes. +1 will place it in zone VI.

Robert Budding · Aug 27, 2010

Yes. The metered reading will place whatever you've metered on Zone V. Add exposure to move to a lighter zone.

tkamiya · Aug 27, 2010

Thank you VERY much.

eddie · Aug 27, 2010

As an aside, when I taught this stuff ( many years ago) I didn't have my students use plus or minus exposure compensation. I had them use the camera manually, and open up a stop ( in this hypothetical situation), as they seemed to grasp the concept better when they had to adjust the aperture. You could almost see them thinking, " OK, my meter says 1/60 at f.11, so I need to shoot at 1/60 at f.8." It did help reinforce how exposure works.

jeffreyg · Aug 27, 2010

tkamiya,
You are not correct as eddie has mentioned. Your spot meter is reading reflected light off your subject. The meter 'believes" that it is reading off an 18% reflective surface so depending on the reflective property of your subjects skin it will want to place it accordingly. Invest in a gray card and do some reading on the zone system. Shifting zones can also involve modifying development time.

tkamiya · Aug 27, 2010

Um.... but, but, but... eddie said I was correct in his last update...

Can you tell me exactly, please, why you think my logic is incorrect? (and I did misstate the zone number. I want zone 6, not 4). Thank you.

Yes, I do have a gray card.

eddie · Aug 27, 2010

Once you realized you wanted a zone VI placement, your logic was correct.
If you decide to use a gray card for metering, you will not need to compensate for the exposure.

tkamiya · Aug 27, 2010

Thank you again, Eddie.

jeffreyg · Aug 27, 2010

You can take a reading off the gray card held in front of the subject's face and then one off the subject and compare to see what zone their face actually is in. Setting your exposure to that of the gray card reading should give you a correct exposure. Does your subject have light or dark skin? I assume you are using B&W film ? That will have decent latitude so if you are off a little you can compensate in printing. These answers are brief but there are many books on the zone system. Once you get comfortable with it you should be able to judge what zone areas of your composition fall in. An incident light meter will read the light falling on your subject.

eddie · Aug 27, 2010

I'd still recommend doing it manually.

tkamiya · Aug 27, 2010

Gentlemen,

As I said in initial post, this is more of a thought exercise for me to see if I understand the zone system clearly enough to apply it to the real-life situations. I do own a light meter, gray card, and a camera with manual capability. Thanks again for helping me think this through.

Taka

jeffreyg · Aug 27, 2010

Personally I use a Pentax 1degree spot meter and always carry a gray card just in case. I found an acrylic gray card and cut it into a convenient size. It has lasted for many years. Calumet may still carry them. I have one in reserve for when i happen to lose it.

http://www.jeffreyglasser.com/

Robert Budding · Aug 28, 2010

Metering off of a gray card is the same as taking an incident reading. I spot meter because I don't always want mid-tones to fall on Zone V during exposure. I may, however, adjust development so they end up there on the developed negative.

RalphLambrecht · Aug 28, 2010

I think tkamiya has it correct now, just as eddie suggested.

eddie
Opening the aperture for exposure correction may help in explaining it to students, but it has the disadvantage over time corrections that it changes the image's depth of field. Hence, exposure corrections through shutter timing adjustments are preferred, because they do not alter the image.

jeffreyg
If one is interested in a realistic rendering, the use of a Gray Card is a great option if an incident meter is not available. However, zone placement as described by tkamiya is a valid Zone System strategy and goes to the heart of visualization.

Q.G. · Aug 28, 2010

RalphLambrecht said:
I think tkamiya has it correct now, just as eddie suggested.

eddie
Opening the aperture for exposure correction may help in explaining it to students, but it has the disadvantage over time corrections that it changes the image's depth of field. Hence, exposure corrections through shutter timing adjustments are preferred, because they do not alter the image.

Spoken as a true still-life photographer...

(I know, i know: you do you take photos of living matter. But that statement... )

Photography students should know that both shutterspeeds and f-stops determine exposure. It's about the first thing they need to know and understand. You can't even begin talking about the ZS if they don't.
So a rather strange thing to say, Eddie.

eddie · Aug 28, 2010

Of course, when I taught, we had already gone over the relationship between shutter speed/f-stop before moving into tone placement. I should have mentioned that but, like I said, it was a long time ago...

Q.G. · Aug 28, 2010

eddie said:
Of course, when I taught, we had already gone over the relationship between shutter speed/f-stop before moving into tone placement. I should have mentioned that but, like I said, it was a long time ago...

I just would have thought that at that point, all you should need to say is to give it 1 stop more or less exposure, assuming they should know how to do that.

Exposure compensation and zone system - am I thinking correctly?

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