The Seven Stop Photograph
The Seven Stop Photograph
What you have here is a VERY old technique to having one image with a huge dynamic range. It’s posted here more as a historical piece then as a technique I use everyday. This 2002 approach does show though I was thinking about and producing techniques for huge dynamic range from nearly the very beginning of my DD work.
Highlight detail, shadow detail, full tonal range, blocked up highlights and muddy shadows: ever come across these problems in your images? How about when you have a gorgeous scene in front of you and you know the range of light is beyond the film so you naturally turn to the Split Graduated Neutral Density (SGND) filter. Once applied, you realize that its straight line cuts right through the subject you want lit rendering it useless.
The range of light is greater then our film can hold detail in the high-lights and shadows. We HAVE TO recognize that fact at the time we TAKE the photo to make this work! Exposure compensation isn’t going to make it happen, in one frame even with the jack-hammering of Photoshop
These are just some of the challenges we photographers face as we chase the perfect light in our perfect photograph. We’re basically stuck with a medium that on a good day can capture a maximum of four stops of detail from the highlight to shadows. Many of the dramatic scenes we want to photograph though with dynamic light have an exposure range way beyond the range of our film. We have to sacrifice either highlight or shadow detail. Or do we?
In the photo here, the sky turned black as Blinkies turn on and off to warn that the exposure is beyond the range of the film. You don’t grab light, grab blinkies and learn from them!
Seeing light is the first and foremost “responsibility” of a great photographer. Without light, there is no photograph. Learning light takes time, lots of time. But that learning curve has been reduced by digital with instant feedback and tools such as Highlight Warning (or as I love to call them, “Blinkies”). Digital and the digital darkroom has made it possible for us to quickly, easily and predictably go beyond the four stop range of our film. While there is no limit technically to this technique, I normally use this technique to expand my image tonal range to seven stops of light. It’s really simple to do; here’s the recipe. (Personally, I do this technique shooting the Nikon Nef (Raw) file format, yet it’s not a requirement)
This is a straight shot, no exposure comp. Blinkies as you can see indicated loss
Step 1: Set up the camera on a tripod, frame the shot exactly how you want it and lock down the tripod head so the camera cannot move. Have your Highlight Warning or “Blinkies” active. Make sure your focus is set to manual and not autofocus. If you’re using a zoom, be real sure the lens won’t zoom on its own (use tape if you must). Focus and focal length cannot change or you’ll cause yourself a lot of unneeded grief.
To get the highlights in the sky, I had to dial in -3 stop exposure comp.
Step 2: This first exposure is our shadow detail shot (bright image). Take your first, normal exposure just as always and then preview your image. Note the areas of the image that are “blinking” at you, indicating where you’ve capture no (as in zero) information in those areas. The blinking areas are highlights “burnt up” rendering no information in the photograph.
Step 3: We’re now going to capture our highlight detail shot (dark image). To accomplish this we’re going to dial in minus compensation and take an image. We keep dialing in additional compensation, taking images until we have no “blinking” areas in our image (starting point is -2 stops). You want to affect exposure, using Exposure Compensation only. Changing the aperture to accomplish decreased exposure, shifts your focus point/depth of field, which you do not want. When done correctly, you should end up with just two images, the original exposure (bright image) which has your shadow detail and the second image (dark image) which has just your highlight detail. (Personally, I delete in camera all the images other than the two images I want to use, which makes the workflow a whole lot easier.)
Step 4: Process your images as normal and open them in PhotoShop. You’re now going to combine these two images in the digital darkroom to retain both the highlight and shadow detail. (There are many ways to accomplish this same thing in PhotoShop, this is just my preference.) Tap the V key to
access the move tool. Click on the “dark” image (highlight detail) and while holding down the SHIFT key, drag the dark image on top of the light image (shadow detail). By the camera being locked down when you took the photos, you took advantage of the pin registered nature of digital cameras so by using the Shift Key, image registration is done automatically for you. The Shift Key when depressed will perfectly align the two images. Note that when this is done, Photoshop created a new layer from the dark image. (If at this point the images don’t perfectly align, you’re in for some long nights with the Ctrl T command. Best to get it right, right from the start.)
Step 5: At this point I close the original highlight image and then tap the F key to go to Full Screen mode. We now need to create a Layer Mask in the new layer we just created. This is so we can “punch holes” in the mask to let through only those
elements of the highlight photograph desired. Depress and hold the Alt Key (Option on Mac) and click on the Add layer mask icon at the bottom of the layers palette. When done correctly, you now have a black or filled layer mask in the “dark” image layer and you now see the shadow detail image on your desktop. We just “hid” the dark image by doing this. The rest from here is real easy.
Step 6: You now want to punch holes through the mask to reveal the highlight detail you want to include in your photograph. Using the Brush (tap B), select a largish, soft edge and work at 20% opacity. You need to make sure your foreground color is white to reveal because the mask is black (which conceals) Work the image by painting in the highlight detail you want. At 20% opacity, it will take many strokes (a click starts 1 stroke) to fill in 100% of the highlight information. You’re going to literally paint in the highlight detail YOU desire to include in your photograph to communicate what YOU want to communicate. The beauty of this system is you can include only the detail you deem important to what you want to communicate. (If you reveal too much, you can always change your foreground color to black to conceal what you just revealed.)
Step 7: In this particular scene of the headstone, I couldn’t use a SGND filter because the trees in the background are at various elevations. This method was the only way to have the highlight detail of the clouds in the sky I wanted, which I determined at the time I took the photographs (not afterwards, in the computer). If you hold down the Alt Key (Option on Mac) and click on the layer mask, you can see the holes that were punched through the mask to let the highlight detail come through. You can see how I used some of the underexposure to emphasize the “mood” of the graveyard by painting in some darkness around the headstones.
Step 8: Once this blending of the two images is completed, I simply come in with nik Color Efex Pro 2.0 Brillance/Warmth to finish off the story telling. While I’m doing all of the work on a Wacom 18SX, you can do it with a standard mouse, it just takes a bit longer.
Once you’ve done a couple of these, it will only take you seconds to do the digital darkroom work. Note that this technique only works when you take the photographs right, right from the start. If you don’t have the camera locked down and exposure compensation dialed in via the EC button, you’re in for a lot of darkroom time. This is a very effective technique for bringing all the detail to your image that your eyes saw and mind recorded that the film just physically cannot in one capture. This is information our film can’t hold in one exposure, but it can in two and now that you know the techniques, you too can have an image with seven stops of light!