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on Jun 23, 2009 in Digital Darkroom

High-Low Merge

© Moose Peterson

There I am, butt in the air with my face against the netting. With my lens up against the netting, I peered through the viewfinder at the Hen from Hell, staring right back at me. The light was that gorgeous late afternoon light that sets a subject aglow. I shot and I shot and I shot, the action and the light just sucked me in so I just kept shooting. It was an amazing climax to an amazing day. I couldn’t wait until I had the images loaded on the computer and up on the monitor. After dinner, after loading all the day’s images I called them up and started through them.I’d gotten through the majority of the images when it finally dawned on me that the images were missing something. I looked and looked at them, used the compare feature in DigitalPro to do side by sides and that something that was missing just didn’t register.

I’d gotten through most of the day’s images when I came to the images of the Hen from Hell. I was very excited getting to and looking at the images. For a moment, that missing feeling disappeared and I went through the last images of the day. I deleted those I didn’t like, tagged those I liked and then sat back and looked at these last images from afar. That’s when that feeling came back, something was missing. It was then, looking at those images of the Hen from Hell in the pen that it hit me like a lightning strike (which was tearing apart the night sky outside my hotel).

Images to combine

The edges of the image, which are the edges of the pens in the photo, aren’t tack sharp and they aren’t straight. I went back through all the images from the day and that was it, that zinging edge to edge sharpness I’ve come to expect just wasn’t there. Would anyone else see that, especially in images on the printed page like here? I doubt it. Would you see it though in a large print? Yeah, I’m afraid you would. That’s when it hit me that I needed to get an ol’ friend back in my bag.

Back in 2003, I sold my 14f2.8 for one basic reason. It can’t be used with a polarizer or split graduated neutral density filter. I didn’t sell it because it wasn’t sharp, quite the contrary, it’s blazing sharp and rectilinear to boot! That means the elements at the edge of the frame stay sharp and linear, they don’t become soft or bowed. But its scalloped built-in lens shade prevents the flush mounting of any filter. Well what has changed then that I would consider getting the 14mm again because it still can’t accept filters? The SB-800 and its ability to totally control the light from the camera for all my projects makes using the 14mm a whole lot easier. More importantly though for my landscape work where I really use the split grad and polarizer, Photoshop (which was non-existent in my world in 2003) makes the 14mm a must again. I’ve written about the 14mm in the past but not the Photoshop, so let me give you some ideas for post with the 14mm.Shooting the 14mm with Photoshop in your pocket.

Light being light combined with the fact that the 14mm captures so much of the world, you’ve got to do something to bring the range of light down within the realm of our medium. With digital, we have five stops maximum before we go beyond the range of our dmax. When you have more than five stops, a split grad is a must but since that’s not an option with 114 degrees of coverage we need to do it in post. Even though we’re going to be doing the finishing work in post, you have to know that at the point of capture to make the post portion work. You have to rely on your photographic skills as much as post skills to have a finished visual communication.

There are times when I have less than five stops in a scene, less than three stops and I still want to use a split grad to bring some drama to the otherwise flat light. This first technique assumes you have an image that is within five stops and want to add some drama. Here’s how simple it is.

Photoshop Split Grad

Layer StyleStep 1: Open the file (thought I’d give you an easy step first).

Step 2: Create a “darken” adjustment layer by clicking on the Zen Symbol at the bottom of the Layer Panel, clicking dead center on the curve and pull it down diagonally to the lower right corner and click OK.

Step 3: Tap X to make your foreground color Black.Step

4: Tap G and be sure you have your Gradient tool active. (You might see the Paint Bucket Tool when you tap G: simply click on the drop down arrow in the box and select Gradient tool.)

Step 5: Click at the top of the image and draw a Gradient line down to about halfway in the photo. There you go, you’re done!What if you take your shot and you see blinkies all over your LCD? You have your highlight warnings turned on and they are telling you that you have way more than five stops of light? What do you do especially when the information you’ve lost in the highlights is information you need? Just to compound things, you can’t use a split graduated filter. Whether you’re shooting with a 14mm or not, this technique will work when you’re up against this problem.

Start by understanding you need to take two images, one with your base or normal exposure and one with an exposure for capturing the otherwise lost highlight information. With your camera on a tripod and set to manual focus, take your first exposure. Look at your LCD monitor; if you see blinkies, dial in -1 stop compensation and take another photo. Look at the LCD and if you still have blinkies take another photo, but this time with -1.5 stops comp. Continue on until you have a second image with all the information you want in the highlights. Next, head to the digital darkroom to combine the two files into one, creating an image with full detail.

There are many ways to accomplish this next step. I’ve gone through a few methods myself, but this is my current favorite way of doing it.

7 Stop Image

Step 1: Process the raw files with your favorite raw processor. I personally use Capture NX.

Step 2: Open Photoshop and head to File > Scripts > Load Files into Stack. With the dialog open, click on Browse and select the two files you want to merge together. With the two files in the dialog box, click on Attempt to Automatically Align Source Images and click OK. (Note: Despite how much you work at not moving the camera, at times it does move a giggle. In this case, the tripod sank a hair in the sand so the images weren’t perfectly aligned.) Photoshop will produce one image with two layers that are aligned when all is done.You now have a number of options of blending the two images. This is for when you have just barely over five stops of light.

Step 1: We’re going to play with blending modes in a sophisticated way. Make sure your highlight or the “dark” image is the active layer. Head to Layer > Layer Style > Blending Options. When you click on Blending Options a dialog box appears. We’re going to use this to “hide” the shadow areas of the dark image, which contain no information we want and to retain the highlight detail we do want.

Step 2: Grab the dialog box bar (at the top) and move the dialog box out of your photo so it’s not covering up parts of the image where you’re trying to bring out highlight information. At the bottom of the Layer Style dialog box in the middle of the box you’ll find a Blend If section. We’re going to move the left slider of the This Layer to the right. We’re going to move that slider to the right until we see sufficient shadow detail begin to appear. The first few times you do this, you will get confused so you must persevere because it is the fastest and easiest way to blend two images.

Step 3: Once you have moved the slider to the left and you see that shadow detail appear, stop moving the slider. Now, while holding down the Alt/Opt key, click on the left side of the slider you just moved to the right, and move the left half of that slider all the way to the left. Click OK. You’re now basically done, you have combined the two images, retaining the highlight and shadow elements that you couldn’t capture in one photo. Finish by changing the Blend Option to Darken (and you might want to play with Opacity, lowering it a tad) and click OK.

When you have six or more stops of light, you might want to combine the above method with this, or use this method all by itself. You might want to go in and finish your photo a little further. Here are a couple of steps I like to do.

Layer Mask

Step 1: With the top layer active, click on the Zen symbol at the bottom of the Layers Panel. That just created a layer mask, white, in that layer. White indicates that all the steps we just did above are being permitted to come through the layer. I often want to hide some aspect of the darker image to bring out some drama the computer simply couldn’t see. So I’ll paint with black (Tap X to make the foreground color black) to hide some elements of that top layer. Using the Brush (Tap B) and working at 20% opacity (Tap 2), I simply paint to taste.

You might be asking, “Why not just use HDR?” I personally don’t like HDR because I don’t want the computer to be in control of what I see or don’t see in the image. We didn’t guess when we took the two photos, we knew exactly the information we wanted in both the shadows and the highlights. Why go back to guessing and let the computer do it when it just takes seconds and a very simple Photoshop technique to be in complete control? After you do the above techniques once, you’ll master ‘em!

You might be wondering about the polarizer. Well, you can do a real nice job of that using Nik’s Polarizer. You can apply it to the Raw file in Capture NX or, you can use the Photoshop plugin. Either way, while not perfectly replicating applying a polarizer to the lens, this will get you mighty close.

© Moose Peterson

Writing a recipe for mastering flash to get it all right in camera when shooting with the 14mm isn’t as easy. But the evolution in technology in just four years has made it very possible to take advantage of a great lens and still have complete control over what we’re visually communicating. I’m so glad I learned some techniques that permit me to have the 14mm back in my camera bag. Every time I zip open that compartment and I reach for the 14mm, I say hello ol’ friend!

Grab the PDF version of this article which originally appeared in the BT Journal.