Written 8 years ago by Mark Evans
If you have seen these sorts of images on the internet or in magazines then you may have noticed that they have a certain look about them.Ã‚ Opinions are divided on whether this look is good or bad, and in my opinion, I quite like the look, as long as its not over the top. But like it or not, it provides photographers with a new alternative for creatively displaying images.
HDR (High Dynamic Range) images have been around for a while, but have seen a surge in popularity in the last few years, due in part to the increased availability of HDRÃ‚ imaging software like Photomatix.Ã‚ These types ofÃ‚ software go some way to taking the pain out of the creation process, by aligning and combining images, leaving the photographer to tweak various settings to achieve the desired result.Ã‚ But before you start tweaking, you’ll need some images to play with:
An Introduction to HDR
Images taken with most cameras today can only capture a limited range of brightness without under-exposing or over-exposing the image. HDR imaging looks to increase this range by combining the dynamic range (brightness values from shadows to highlights) from a series of images of the same scene into one HDR image. You’ll probably find that the best candidate for an HDR image will contain a large dynamic range ie shadows and highlights, and a scene with a similar spread of brightness i.e. all shadows, or all highlights, will tend not to work so well as an HDR image.
Creating Your Own HDR Photographs
When it comes to capturing a scene for an HDR image, you must first capture a series of images at different exposures to cover the dynamic range of the scene (exposures for shadows and highlights). Generally the easiest method is to take 3 images with an exposure bracket of 2 stops. i.e one image at -2 stops, one at correct exposure, and one at +2 stops. Most prosumer cameras have an exposure bracketing function, so set this to 2. To make it easier in the end, it is advisable to use a tripod to capture your images, this way you will avoid image alignment issues later on.
Just remember there are no hard and fast rules here, so go out and experiment, I have found I generally get better results when I use a series of 5 images using a 2 stop bracket, i.e -4, -2, 0, +2, +4. But thats not to say it is best for you, it will depend on the scene you want to capture. Try bracketing at 1 or 1.5 stops, mix things up a bit, see how you go. The important thing to remember is to try and cover the whole dynamic range of the scene, from the shadows to the highlights, so that your final HDR image has as much information in it as possible. Below I have tried combining 2 images, one with the correct exposure for the dark foreground and one with the correct exposure for the lighter background. This resulted in a fairly natural looking image, although more exposures would have resulted in a higher dynamic range image:
Another way of getting your series of images is to use the ‘exposure’ function in photoshop.Ã‚ So if you only have a single image to work with, open it in photoshop or similar, change the exposure and save as differently exposed images. I find that generally I dont get as good results doing it this way because obviously you cant create more information from doing this, but some worthy results can be got, so worth a try none the less.
- Requires a series of images of the same scene at different exposures
- Popularised by software such as Photomatix
- Great for extending the Dynamic Range of an image by combining exposures
If you have had experience with HDR imaging and have some useful tips for other users, then please share them using the comment form below.