Posted by David Peterson on 16 Jul 2008 as Composition, Exposure, Outdoors, Software, Tips
Another email I received this week was from Mark Jones. Mark writes:
I would like some advice on the attached picture. I tried to photograph my band playing a gig in a pub and the light was shining through the window meaning the drummer/guitarist was in almost complete dark, how?why? What should i have had the camera set to?
This unfortunate situation happens because the camera can’t see as well as our human eyes can. We would look at this scene in a pub and would be able to make out both the band, and the scene outside. A camera can’t do as well.
Scenes like the band photo, and the photo of the child to the right have what is called a high dynamic range. That is, they have bright sunlight and dark shadows. It is impossible with current technology to have both parts of the photo correctly exposed.
While you can’t eliminate the problem entirely, there are a couple of choices you can make to minimze the problem.
This is probably the simplest solution. When taking a photo of a scene with very bright and very dark parts, move your camera to eliminate one of the extremes. In the case of the band, I would have either closed the curtains for the shot, or recomposed completely and photographed from the window looking at the band, and the crowd behind.
If you can’t recompose the photograph, instead tell the camera what part of the image you would like to see. The rest of the photo will be either over or under exposed (too bright or too dark) but at least you will see your subject. You can do this by placing the center of the image at your subject; half depressing the shutter to lock the focus and exposure; move the camera to re-compose the image; and fully depressing the shutter.
In the band image, the camera chose to correctly expose the scene outside, but even if the band member had been correctly exposed, the window would have ended up being over exposed and you would just have seen white.
Some cameras have an option called ’spot metering’ to set the part of the image you’d like to be correctly exposed. If your camera has this setting, enable it before using the technique above.
If your scene has a sunny background, but your subject is in the shade (or has a hat on), turn on the flash (as I explained way back in tip number 9 - Using Flash During The Day). I know it seems wrong but it really does work! By using the flash, your subject will look as bright as the background. This would have worked well for the child shot above.
This technique is not for the faint of hearted. It requires a subject that does not move; a good camera with the capability to set the exposure and output RAW images. A tripod and image editing software like Photoshop CS3 are also needed.
High Dynamic Range Imaging (or HDR for short) is a technique for placing both very dark and very light areas in the same photo. It requires you to take a number of photographs of the same scene - each with a different exposure. First take the shot using the camera’s recommended settings. Then, in manual mode and keeping the aperture at the same value as the first shot, take a sequence of shots - each shot having a different shutter speed (above and below the original). You’ll have 5-9 shots of the same scene all in different exposures.



Merging the three images to the left creates the HDR image below. Thanks to Photomatix for the images.
Now import these into your favorite paint program. I use Photoshop, but you can as easily use a cheaper program designed specifically for HDR photos like Photomatix. Follow the HDR directions and the paint program will merge these images into one great looking shot!
If your scene is of a bright sky and a dark ground (for instance at sunset, or on a cloudy day), you can use a graduated neutral density filter. This filter cuts out some of the light from one part of the photo (the sky). This will correctly expose the ground and the sky without needing to use HDR. These filters can be complex to setup, so I don’t usually recommend them for beginners.
Finally, if you can’t take another shot at the same location, you can fix the original image by changing the levels using a paint program. This works best when your subject is darker than the rest of the photo (because cameras lose detail in over-bright areas). I’ve brightened the band member in the top image using this technique and while it looks okay in this small shot, this technique can tend to amplify any noise in the image. The darker the subject, the harder time you will have fixing the image.
I discuss exactly how to use this technique in lesson 2 of my free Image Editing Secrets course. I have a tutorial for Photoshop, Photoshop Elements, Paint Shop Pro and the free Google Picassa.
5 Responses
Lu Schmidt
July 17th, 2008 at 12:49 am
1I consider myself to be an accomplished amateur photographer, with a lot to learn. I’m always looking pick up tips/info that I do not know. The info on HDR is facinating. Can’t wait to try it.
Suzanne
July 17th, 2008 at 12:40 pm
2David,
I was asked to spend about 30 mins talking to kids 8 years to 18 years old about photography for a fun and for future income. How I got into photography, the thrill I get doing it and a little about photography itself.
I would like to bring you along…well, three of your articles entitled “The 4 Top Causes of Blurry Photos, And How To Fix Them”, The article that starts with “ISO Explained” and this last one, “Camera Hieroglyphics Demystified: The Camera Lens”, of course, with your permission.
This Career Day is once a year for At Risk Children that are interested in dogs and horses. Since I am a dog and family photographer, I was asked to attend. There will be about 12 children with their parents present.
Would you mind if I used these articles that are very well written and at the level that not only I can understand, but they they can understand too?
I have written your email address at the top of each article and your name and date are on the top too.
If you have a problem with me handing out these articles please email me and I will not do it. I just wanted you to know that I appreciate you and all of your information put into simple language. There is so much information out there that I sometimes get overwhelmed.
Thank you again,
Suzanne
http://slickimages55.googlepages.com
David
July 17th, 2008 at 5:23 pm
3For those of you who use the GIMP, you can get an HDR plugin for it as well.
David
July 17th, 2008 at 5:25 pm
4Sorry, I didn’t realize that the URI for the GIMP HDR plugin wouldn’t show in my post. Here it is: http://registry.gimp.org/taxonomy/term/410
David Peterson
July 24th, 2008 at 2:54 pm
5Suzanne,
Yes, you may use my tips for your class. I usually allow anyone to use my tips for any offline purpose as long as my name and my website are printed with it.
David.
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