How To Create Single Frame HDR Images - zev

How To Create Single Frame HDR Images

Jan 27, 2014

Brooklyn Skies

I'm a fairly recent convert to HDR photography.  I love the look and feel that can be created in HDR photography that simply cannot be created using conventional means.  


Normally, to create an HDR photograph, you will have multiple images of the same frame exposed at various levels.  I usually use seven frames, exposed from -3 EV to +3 EV.  So, for example, I'll shoot the same scene at 1/250 of a second, then at 1/125 of a second, then 1/60 of a second and so on until I have the seven images.  I can then blend them together using Photoshop or some other program until I achieve the desired result.


However, sometimes, you can't get multiple images.  You might have shots of moving people -- and you can't ask a group of people to remain motionless while you set up and take multiple shots.  Or perhaps you don't have a tripod and therefore can't accurately capture multiple frames.  Or maybe, you only have a single frame because you weren't thinking about the possibilities of HDR photography at the time.  


The good news is, it is possible to create HDR-like  (often called faux-HDR) photos with just a single image.  The image above, Brooklyn Skies, was created with just one image.  It's actually quite simple to do, and I'll show you how.


I took this shot while visiting my mother in a rehabilitation center in Brooklyn.  It was an unplanned opportunity.  I hadn't visited her there before and I had no idea that she had that kind of view available.  I was glad that I had brought along my camera that day.  I didn't however, have a tripod with me, nor was I even really thinking about HDR photography.  As a result, I only have the single image, not a series of images at different exposure levels.


Now, we're going to take this image and make it an HDR-like photo, like the one above.  It won't be exactly like the one at the top of this post because I'm going to use Photoshop for this example and I used a different program for that.   But the process is still pretty much the same and you can achieve some excellent results in Photoshop.



The first thing you have to do is open up your photo in Photoshop.

HDR requires multiple images at multiple exposures.  However, in our case, we don't have that -- we only have the single image.  So, we're going to create our own multiple exposures.  


When you have the photo open, create a new Exposure Adjustment Layer.

(Click on the half-white, half black circle in your layers, palate and choose Exposure)

When the exposure panel comes up, bump up the exposure to 2.  You can either move the slider or simply type "2" in the box.


When that's done, save this as a JPEG with a new name.  I like to append "_plus2" to the filename so that I know, at a glance, that the exposure is two stops higher than normal.

Next, we're going to create an image where the exposure is two stops *below* the original image.  You can either delete the exposure adjustment layer you created above and create a new one, or simply adjust the one you have.  


In the exposure box, type "-2" and save the image. I like to append "_minus2" to the filename.

Now, you should have three files -- one at the correct exposure, one that is overexposed by two stops and one that is underexposed by two stops.

Now, we're ready to begin the process of merging these images together.  


Close all your photos in Photoshop.  Then go to File -> Automate -> Merge To HDR Pro.

When the Merge To HDR Dialog box comes up, choose Browse and navigate to your photos.  Highlight all three of your photos and press "Open."

Photoshop is going to start loading the files and processing them.  Depending on the speed of your machine and the number and size of the files you're using, this can take up to a few minutes. 


In order for Photoshop to properly merge the files, it has to know how over or underexposed each photo is.  Photoshop will now ask you how far over- or under-exposed each image is.  When the "Manually set EV" dialog box pops up, click on the EV button and type the exposure into the box.  In this example, the 2-stop-overexposed image came up first, so I typed "2" in the EV box. 


When you're done, click the right navigation button to go to the next image.

The next image that comes up in our example is the underexposed one.  So, we choose the EV radio button and type "-2" in the EV box (see image below).  Then go on to the next image.


The third image is the properly exposed one for this put "0" in the EV box.  Note: there is no picture fro this step.  I assumed after the previous two, you didn't need another one.)


After you have manually set the exposure values for all the images click OK.

The third image is the properly exposed one for this put "0" in the EV box.  Note: there is no picture fro this step.  I assumed after the previous two, you didn't need another one.)


After you have manually set the exposure values for all the images click OK.


This will bring up the Merge to HDR Pro diaglog box.  This is where you can fool around with different settings to create different looks and feels for your photo.  Go ahead, fool around with the sliders and the drop downs until you get an image that you like.  After that, simply click OK and you're done -- you have your first faux-HDR.


If you have any questions, please feel free to ask.  Also, I'd love to see what you create using this method.  Feel free to post a link to your photos in the comments section.


Zev




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