Sunday, March 4, 2012

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The Basics of HDR!

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So why HDR?

A HDR photo offers a much higher dynamic range as compared to a regular photo. Take for example, a EOS 7D has a dynamic range of 11.7EV. HDR effectively increases this to 17.7EV, a 51% increase! But HDR doesn't come as easy as a flick of a button. Firstly, the settings have to be right, and then comes the post processing on the computer. With more people opting to do a HDR photo, new higher-end Canon camera bodies such as Canon EOS-1D X and 5D MkIII have HDR feature built right into it. I haven't been able to get my hands on a HDR compatible model, but reviews suggest that they are promising.

There are other reasons to why people do a HDR, but increased dynamic range is why most people do it. For me, I do it for the increased dynamic range, and the colors I can create on a HDR.


So why not HDR?

If HDR sounds so good, why not use it all the time? HDR is useful for still scenes such as landscape because if the subject or background moves, it does not align during post processing and cause ghosting (covered later). HDR pictures may not qualify in some photo contest because it may be considered as manipulated pictures under some T&C's.


How to create a HDR?

There are 2 parts to HDR: In-camera settings & Post processing.


In Camera

In camera, go to menu and look for Expo.comp./ AEB or anything other thing that look like this:


Click into AEB and turn the dial on the camera clockwise until 3 lighted strips can be seen below:


(Do not worry if your camera cannot reach +/- 3. Some cameras can only reach +/- 2.)

And you are good to go! I highly recommend a stable tripod when shooting HDR, and using the timer function on your camera to reduce all possibilities of camera shake. I also recommend shooting in RAW file format if possible, and turn off image stabilizer if your camera lens has one. (Some professionals claim that image stabilizer will degrade image quality when shooting on a tripod. Well, the thing is, you don't need image stabilizer if you're on a stable tripod anyway. For me, my landscape lens does not have image stabilizer anyway.)

Take a test image and check that there should be one underexposed photo (-3.0 EV), one correctly exposed photo (0 EV), and one overexposed photo (+3.0 EV). Once you see them, you're on the right track!


Post processing


In post processing, there are several software that can help you combine and process your HDR files. I use Photomatix to combine the pictures together before sending it over to Adobe Photoshop for more post editing. Photoshop allows you to combine HDR files as well, but I felt like it doesn't serve my needs as well, so I'll still go with Photomatix.

I shall not post too much screenshots on basic Photomatix functions because they can be found in the tutorial within the application.


1) Open photomatix
2) Click "Load Bracketed Photos" and load the 3 images shot at -3.0 EV, 0 EV, and +3.0 EV.
3) Accept the default settings and press OK.
(There is 1 checkbox to reduce noise and 1 to reduce chromatic aberrations left unchecked by default. I don't find these feature useful because it don't see a difference in it's noise reduction feature, and I prefer to correct chromatic aberrations later in Photoshop later for more accurate results.)

4) Skip the "Selective Deghosting" step by clicking OK.
(Ghosting occurs when subjects or objects in the photos differ between the images used to build HDR. It is rather tricky to deal with ghosting, because Photomatix does not resolve ghosting well.)

5) You are now presented with a horrible HDR picture. Don't worry. Things will change for the better. Save this image by going to "File -> Save image".
6) Click on the button "Tone Mapping / Fusion" and instantly, your photo looks much better now.


You can accept the default settings or choose one of the presets available, but they don't work well for good photos.

Now for the most important part of this tutorial! Playing with the sliders. We are not going to use all of the sliders. About 6 to 7 at most.


- Strength: You can adjust the slider keeping in mind not to destroy any colors that you would want to work on later. For example, pushing the slider to 100 will turn most of the sky to dark blue, almost grey, which is something we don't want to edit on. Be sure not to push the slider too low, or some parts of the photo will overexpose. I usually keep this slider between 60 to 80.

- Saturation: A little saturation may make the photo look great, but I don't like the saturation colors on Photomatix. So I will normally keep it default, or push it up a little to get the color to work on Photoshop later. I usually keep this slider below 60.

- Detail Contrast: I skipped Luminosity to be edited later. Although I like my photos nice and detailed, this slider creates too much noise in the image for the small amount of extra details it can bring out. The effect quite similar to using unsharp mask on Photoshop. I won't recommend, so use this sparingly.

- Lighting Adjustments: This slider increase the brightness of the light areas and decrease the brightness of the dark areas when pulled to the right, and vice versa. I usually keep this value low, between 0 to 3.

- Luminosity: If your photo turns out a little dark after Detail Contrast and Lighting Adjustments, you can adjust this slider to bring it back up to the correct brightness.

- Micro-smoothing: This slider smoothes out small details and reduce noise, but too much of it makes the photo look like it has less depth. I normally keep this low, between 0 to 4, as I can tackle the noise later in Photoshop.


I normally do not touch the rest of the sliders for a basic HDR.

When you're done, hit the "Process" button! Save the photo and you can bring it over to Photoshop for more editing! If your photo looks rather similar to the default, don't worry, because subtle differences goes a long way in photo editing.

There you have it! You have a HDR image! If you like this tutorial, don't forget to like and share it! In the next part of this tutorial, I will talk about editing the HDR photo on Photoshop, and how to make them "POP"!

2 comments:

  1. i'm waiting for you posting about editing the HDR photo on Photoshop. :D

    Just FYI, there’s an event for bloggers and the prizes are iPad2 and Cash. Find the info in my blog

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  2. Thanks kurnaen! It's coming soon, I promise! Quality post takes time to do..

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