Why HDR on the iPhone Is a Good Thing and How to Use It

What is HDR photography? It is a defined as:

a set of techniques that allow a greater dynamic range of luminance between the lightest and darkest areas of an image than standard digital imaging techniques or photographic methods. This wider dynamic range allows HDR images to more accurately represent the wide range of intensity levels found in real scenes, ranging from direct sunlight to faint starlight. 1

In terms that really make sense though you use your camera to take on average 3 pictures each is taken at different exposures. One at a normal exposure, what you would expect to get when you take a normal picture. Then one over and one under exposed. Essential you have one normal picture, one brighter picture and one darker picture. Using digital tools you then overlay these three images taking the best of each to create one composite image as the final.

HDR however has gotten a pretty bad rap online as many people have been using tools like Photomatix to ‘over process’ their images, resulting in a fantasy land look to them as you can see below:

HDR 1

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HDR 2

Source

This over processing has lead to many people writing off HDR as nothing but a fad. This over processing is a fad, but HDR is not – HDR is a serious tool that can help make a picture that looks more like what the human eye actually sees. This technique is widely used in Real Estate photography as seen in these examples:

HDR 3

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HDR 4

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Where without the use of HDR you would need to have ample strobe (flash) lighting to be able to get something other than bright white in the windows.

Now that we can see what HDR really does when used correctly we can get a much better sense as to when we should be using it.

HDR on Your iPhone

There are a couple things to note about using HDR on your iPhone so let me just run through those really quickly:

  • The implementation is not perfect.
  • You can’t edit the processing.
  • It takes longer between shots.

With those three things in mind we can move forward with HDR on the iPhone. The default setup for the iPhone is to ask you after taking your first HDR picture if you would like to save the original image as well as the HDR image. For most I recommend leaving this option on, you get the ‘normal’ exposed image and the HDR version both saved on your phone. The time between shots suffers a significant delay when HDR mode is on, often taking about 6 seconds between the time you take a picture and the time you can take another image. 2

There are two criterion that you really should be looking to see if you meet before you think about using HDR:

  1. Is the background of the image going to be brighter than the foreground? For instance is it bright and sunny out, and you have someone standing in front of a window? Then typically the window would either show blue sky and the person would be a silhouette or the person will look great with a bright white background (this is called a blown out background).
  2. Nothing important should be moving. Remember you are taking three pictures in rapid succession, so if your subject or things in the background are moving you are going to get ghosting (which looks like this and this.)

So HDR is best used for things that are not moving (real estate, landscape, a posed portrait).

Personally I leave HDR on at all times, I know I get the normal image with the added benefit of just maybe getting an even better version from HDR. Here are some examples of images I have got using HDR, with the normal exposure comparison.

husky.png

husky_hdr.png

office.png

office_hdr.png

vase.png

vase_hdr.png

wedding.png

wedding_hdr.png

conf.png

conf_hdr.png

As you can see I have not had a chance to take many shots, but what I have taken has on average been better with HDR on.

  1. Wikipedia
  2. With HDR off it takes on average, less than 2 seconds.
Originally posted for members on: September 21, 2010
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