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Peter De Smidt
17-Dec-2014, 08:53
I'm going to start getting a little more serious about black and white studio portraiture with flash, and I want to make sure that I'm going about exposure/development testing in the proper way. For outside use, I find what film speed will give a Zone I reading of an evenly lit black card in shade of at least .1 above film base plus fog. I determine development by using the previously determined EI and photographing an evenly lit white card in direct sunlight and placing it on Zone VIII. The development time that gives the appropriate relative density for zone 8 for my output process gives me my N development. That's all standard enough. Exposure determines shadow values primarily and development mainly determines the lighter values. With studio portraiture, though, the shadows are primarily determined by exposure plus fill light, and since fill varies... Is the proper way to go about this is to use the same exposure and development times for studio flash portraits that are used for outside photos, adjusting the fill level to taste, or should there be an EI/development testing procedure specific to the studio work used, and, if so, what should the process be?

Ken Lee
17-Dec-2014, 09:40
Presuming that the lights provide a spectral curve similar to daylight, it seems logical to adjust the fill to match what we already know about the film/developer combination.

Color aside, the only other consideration I could imagine would be flash lighting of very short duration, where we might encounter a kind of reciprocity failure: that would require testing.

Peter De Smidt
17-Dec-2014, 10:43
Thanks, Ken. I forgot to mention that for continuous lighting situations, I use a Pentax digital spot meter, a reflection meter, whereas with flash I'll use incident meters, either a Gossen Luna Star, or a Minolta...III, I think. I should probably do a test with a white card, flash and an incident meter. As long as the resulting density is close to what I get with my outside tests and the spot meter, I would expect that all would be good.

Ken Lee
17-Dec-2014, 11:24
Used in the conventional manner (a single reading in direct light, pointing towards the taking lens), an incident meter will put Zone V on Zone V so to speak, but won't account for the extremes. If the contrast is moderate, a single reading like this will work fine, but if contrast is excessive the dark values will be underexposed and the high values overexposed.

<start nutshell>
You might find it even more helpful to use the BTZS method of incident reading, where we set the film speed on the meter to twice its actual value, take a reading in the open shadows, and base exposure on that reading. That will guarantee adequate exposure and roughly equates to placing the "shadows" on Zone IV. To gague overall contrast we take a reading in the direct light. Under normal contrast the difference will be 2 stops and the film will require N development. If the difference is greater or less than 2 stops, we can adjust development (or lighting) accordingly. This method may appear oversimplified but works surprisingly well, especially when it's hard to judge correct zone placement, as in this photo (http://www.kenleegallery.com/html/nikkor200m/index.php#vase). All the photos on that page were metered with this approach.
<end nutshell>

ic-racer
17-Dec-2014, 11:43
The incident meter is well suited to studio work. Especially when a given lighting setup could be used for subjects with differing reflectance. Calibrating an incident meter using densitometery is complicated and involves many sources of potential errors.

Therefore, what I do is to simply make some test exposures of real subjects at various ISO settings on the incident meter and just use the ISO that gave the thinnest negative that gives a good print. Since you are in control of the lighting, overall there is more leeway in exposure, compared to outdoors. So it is not rocket science in my opinion.

Peter De Smidt
17-Dec-2014, 13:13
Thanks, Ken.

Peter De Smidt
17-Dec-2014, 13:20
Ic-racer, thanks. I'll be sure to make some test prints.

Bill Burk
17-Dec-2014, 23:44
You open the door to all kinds of ideas when you shoot in studio. Reminds me why there used to be only one grade of paper for some surfaces intended for studio work, because in the studio you were expected to shoot test setups and adjust light to fit the paper...

You could make the light very flat and develop to completion (like William Mortensen).

Or you could make the light Normal in Zone System terms...

For example, you could uses the main light to place the subject in its proper Zone, such as adjusting the main light to Zone VI on light skin. Then bring the fill light in until the shadows are on Zone I or Zone II. Bring in a catchlight and either carefully place it for Zone VIII or let it blow out a little...

Dan Dozer
18-Dec-2014, 09:10
I shoot almost exclusively indoors with portraits and figure work, and about 70% with strobes and 30% with natural light. I use the same EI and development for my film with all exposures whether they are outdoors, indoors with natural light, or indoors with strobes. If all you are shooting is the exact same set up, lenses, and film, then a testing process might prove advantageous. However, as soon as you try something different, I would suspect that your test results might start to be off track. From what I understand, light from strobes and outdoor light from the sun may require light adjustments in your standard EI/Development times, but I don't know what those are. Most of the lenses I shoot are old lenses that are uncoated, but I have a few that are coated. That throws off the contrast on the negs to the point that I've given up on film testing.

I must have read Ansel Adams "The Negative" a dozen times cover to cover and used to do all the tests as you note. However, at some point, I realized that I was spending way too much time testing and not enough time actually shooting. I have established EI's and developing times for the two types of film that I shoot and it works well for me. These were based on setting up a scene with a wide range of zones (hopefully from blacks to whites) and then trying different EI's and developing times from those. The combination that gave me the best results was what I settled on.

Regarding fill flash, if all you are trying to get is a slight increase in the shadow areas, reflectors many times are better than fill flash. Fill flash is what I use to get the secondary light much closer to the main light.

Regarding shooting with Flashes - you might at some time want to consider getting a flash meter. The Sekonic L-358 is probably the most popular out there and it has never let me down.

Jim Noel
18-Dec-2014, 09:25
The incident meter is well suited to studio work. Especially when a given lighting setup could be used for subjects with differing reflectance. Calibrating an incident meter using densitometery is complicated and involves many sources of potential errors.

Therefore, what I do is to simply make some test exposures of real subjects at various ISO settings on the incident meter and just use the ISO that gave the thinnest negative that gives a good print. Since you are in control of the lighting, overall there is more leeway in exposure, compared to outdoors. So it is not rocket science in my opinion.

The original Norwood exposure meter was designed to answer a need in cinematography. Yes, an incident meter is ideal for the studio. It is easy to use to determine balance between main and fill lights.