This week we are going to explore High Dynamic Range (HDR) photography.
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The photo above is actually two pictures put together.
In the first picture the camera app meters off the building and takes a picture that gives the building good light exposure. Then for the second image the camera meters off the sky and takes the image so that the sky has a good exposure.
Typically a HDR photo is made up of about 5 different exposures of the same image. One shot taken at what the light meter says is the correct exposure then two shots above and two shots below, usually about one stop difference between each exposure. I know, technical talk and right now some of you are going, "huh?" Don't worry, stick with me and it will become clearer.
When shooting with an iPhone taking 5 separate exposures of the same thing really isn't an option.
The iPhone does have an HDR setting built into the camera app. The problem with using this option is that it isn't true HDR. The app only takes one image and then attempts to mimic High Dynamic Range digitally. There are also quite a few HDR apps in the iTunes store that do the same thing. I haven't been impressed by any of them, including Apples version.
I use an app called Pro HDR. This program will take an under and an over exposed image and then combine them to give you a decent image with a good range of light. It's not perfect, as you can see from the image I have above there is a bit of a glow, or halo, right along the building edges. But we are talking an iPhone here, not a full sized digital camera taking 5 or more shots. The halo effect can be taken out using a program like Photoshop if you really need to.
Pro HDR offers both an auto setting and a manual setting. The auto setting works great and I can use it for most of the pictures I take. But every so often I need to switch to manual because auto isn't picking up the dark or light area I want it to. In this example I have it set to manual. You simply slide one box to a bright area of the picture and the other box to the dark area, the app does the rest.
If you decide to download and start using this program make sure to go into the settings and reset them for "full." You want the highest quality images you can get so that you can print them later if you want to.
Since you are taking two pictures of the exact same thing you have to keep the iPhone as still as possible. The exposures happen one right after the other but you want to make sure you don't move the camera between shots. If you do move it you get what is called, "ghosting." You'll see part of each image in the final picture. Pro HDR tries to take out ghosting to a point, but is only successful when there has only been slight movement. More professional programs like Photomatix Pro, which you use on your home computer, do a much better job of eliminating ghosting. Photomatix Pro costs $99, Pro HDR costs $1.99. Since I don't carry a tripod around for my iPhone and doing so would take away from the spontaneity that is iPhone photography in the first place, I usually hand hold my shots. I hold my breath and plant myself as firm as I can so as to not move. Holding your arms against your body helps as does bracing yourself against a wall, post, car, whatever is close by. I'll also set my iPhone on the ground, rock, fence, you name it, to help keep it steady.
The other problem you will run into is that no matter how still you hold your iPhone sometimes your subject moves. When that happens to the main subject of my shot I just try again, if it's the leaves in the tree that are in the background I have learned not to worry about it. Same goes for when you are taking a picture of something and people are moving in and out of your shot, they really do end up looking like ghosts. I live with it.
In the image to the right you can see that the leaves in the trees where moving between shots. They look kinda funky.
This shot is actually more than one HDR picture stitched together. I'll go over stitching multiple pictures together in my next diary.
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Remember: I post this series to the iPhone Photography group, check it out if you want to review my past lessons.
Got questions? Please ask.