Mr An Onymous and I have been experimenting a bit of late with the Exposure modes in the Nikon system. For almost all my digital life, I’ve been a staunch supporter of Nikon’s Active Matrix exposure system.
Briefly it reads the light value of the scene, and then compares that to a database of similar image values and determines exposure setting, f/stop, shutter speed, and/or ISO value to match with the current scene values for correct exposure. Internet gurus (know it alls) may disagree, but its worked well for me the past 15 or so years.
What Mr A and I were experimenting with is the value of 18% reflectance and the need to determine a ‘correct’ exposure.
Now long time blog readers will be quite familiar with my rants on the “Mystery and mystic of 18% grey” and the more memorable “The 18% Grey Myth and how we’ve been Conned”, so there is not need to continue that further tonight.
One of the greatest teachers of the correct use of light, its values and how to gain correct exposure with Colour Slide, (Transparency, or ‘Chromes) was Dean Collins. A US based commercial photographer. I had the great fortune to have attended one of his Seminar events and his clear, concise and skilled explanations of all things lighting was indeed one of the highlights of my life.
Dean’s premise for portraits was to get the Diffused Value of the skin at a specific exposure value, for various skin types, dark, light, tanned, etc. Then set that and either add light for shadow control or remove it for highlight control. There I just saved you the $1000K for the seminar. Thanks Dave!
Dean had established through experimentation that if the Diffused value is correctly exposed then Photographic White, (no detail) would be 2 1/3 stop more exposure and Photographic Black (no detail) would be 4 1/3 below. They didn’t call him “The Dean of Light” without good reason.
The rest is just fascinating tech wizardry and dry boring numbers, so we shall not pursue further other than to suggest that a look at some of Dean’s work will reveal how clever with light he really was. One of the best photos is at the bottom of this blog, along with the whole story,
What is most amusing about this shot, is it was setup with gazillions of flash units running on a sensor, fire the sensor light and all the lights go off. Except. As they were getting ready for a shoot, a Japanese tourist came by, pulled out his little camera and took a shot, and set off every bank of flash, all gazillions of them. 🙂
Today, we can’t in the field, make those changes to the light, but clever Photoshop, and to some extent, Lightroom and others can help. (I’m deliberately avoiding the issue of fill-in flash to help balance out those shadows, in my opinion, it’s so overused and so mostly poorly handled that the results remove the form of the subject)
I loaded the Yellow-plumed Honeyeater file into PS and hunted around with the Eyedropper tool for a value about 127-128 (Mid tone, think Diffused Value if you were paying attention) Not finding one where I wanted it, I raised the Exposure slider until the area just under our model’s chin was as that value. All good.
Now I need a Black of about 4 1/3rd less. Past experiments would say that is the 0 value, right?, but I think it’s better at about 25-30, so I dropped the “Shadows” slider until I was getting 25 in the black under the eye. Next is Photo White, and I hunted around the sky values until I found some that read 255 (white), but again from experience I think that is excessive, so I usually use dropped the “Highlights” slider to a value of around 230-235. Here I went with 235. That way I get a tiny hint of form in the white. (Which by the way look like clouds in this shot, but clever reader you’d be misinformed).
Perfect highlights giving an excellent Hi Key Portrait. Dean would have approved.
And all this because I managed to get a pretty close exposure for the Diffused Value in the first place. Thanks to Mr A’s theory.
This is not a solution for resurrecting badly over/underexposed photos.
Someone at a bird photography seminar once said to me, “Yes, but I don’t do it that way!!!” to which I responded, “True, but then you don’t get the results I do.”
Herein endeth the lesson.
Keep takin pictures, we do.