Multiple Exposures for HDR

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Foundations of Mobile Photography – HDR Photography Tutorial (for beginners to advanced)

By Matt Glastonbury (Matt on Google Plus)

There are different methods of processing HDR images, and here, the type I’m wanting to discuss is going to help you process a better image in difficult lighting situations. We won’t be covering how to create surreal, or super-vibrant, processing effects. My preffered use for HDR is to make images look clearer than they would normally.

What is HDR?
Hyper Dynamic Range: It’s when more than one image is taken with different levels of exposure, of the exact-same scene, then combined to create a photo that looks closer to how you remember seeing it. The range of visible areas and tones are enhanced.

Why use it?
When you face a bright light-source, your camera tries to close down the exposure to let in less light, and subsequently makes a lot of your subject very dark. HDR processing allows you to take more than one exposure of the shot, in different light-ranges, and combine them. So, using it in certain situations can allow you to capture areas of a scene that are not normally possible with a camera, and that are normally only visible with the human eye.

How to use it?
You will need to take two photos of your scene, and one app that is great for this is Pro HDR. This app will take two shots for you and merge them automatically. For greater control on where the app measures the exposures from, try selecting the HDR menu and choosing manual.

Tip: Pro HDR has another method which allows you to manually load your own two photos, taken at different light levels, with any camera app.

With both situations, in the above collage, I used KitCam app to take two separate shots, one light and one dark, by measuring the light from different parts of the scene. (See my Exposure & Focus Tutorial for more on how to do this) I then manually loaded those light and dark shots into Pro HDR by choosing; Actions/HDR from Library, and you can see the results are quite different to both the original shots. It’s the best of both worlds combined.

When to use HDR?
When your subject is not moving too much.
When you can hold the phone still.
When your subject is too dark due to background light.
When you don’t want silhouetting when facing bright light sources.

Below, I’ve used an app called AvgCamPro to generate my two images. We will cover AvgCamPro in a later tutorial, but basically it takes many photos of your scene (you must lean the camera against something, or use a tripod, to keep it perfectly still) and combines them into one, which is essentially similar to HDR. The result appears to be like a slow-shutter capture, but the great thing is, you can increase or decrease the gain slider to produce and save different exposures using the wide range of tones available from the capture, then feed those into Pro HDR.

Finally, another cool use for Pro HDR is to take several exposures with a Slow Shutter app, like Top Camera, at different light levels, and then combine them. Here you can see some interesting results of two independent images taken over eight seconds each, using a tripod, and then Pro HDR to save them as one.

Don’t forget, you can also edit your two exposures separately with different apps, colours, and effects, then combine them using Pro HDR to come up with interesting results.

Tip: If your images/exposures are tonally too far apart (too dark, and too light) you can get unwanted glows, and/or, dark spots occurring in areas on your image, so you may want to take shots that are not too extreme from each-other. With this in mind, I usually take 4-6 shots all with different levels of exposure, so I can choose the best ones when I combine them later.

See what wonderful images you can produce by getting creative with your multiple exposure shots and combining them in an HDR app.

To keep the phone still, I recommend using a Joby smartphone tripod-adapter called the GripTight Micro Stand, or a GripTight GorillaPod, they work really well with most camera phones, and are light and easy to fit in your pocket or bag.

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