Monday, April 27, 2009

HDR = WOW

I had the day off so I went to Indianapolis today. Had to pick up my credentials for the "Greatest Spectacle in Racing." (Indy 500 of course) Always a good day when it's time to get those. After that I went over to the Indianapolis Museum of Art to take some pictures.

The museum has a really great garden, lots of different flowers depending on the time of year, some cool architecture. Just a really nice place to spend an afternoon on a nice warm spring day.


Back in March I picked up a Nikon D700 to replace my D70. The D70 still works great, but after five years it just seemed time to replace it with something that had a little more punch. One of the main things I wanted as the ability to use a remote switch, something the D70 doesn't allow. Plus the full 35mm frame of the D700 means all those wide angles are, well... wide again. And the D70 I will keep around, plan on sending that out to be converted to an infrared camera.


I've done a little shooting with the new body since I got it in March, but nothing too exciting. Figured the colors of the garden would make for some fun stuff. Something else I've wanted to get into recently is HDR photography, High Dynamic Range. I've seen some other people online working with it and it seemed like fun. The first spot I tried was a waterfall that runs through the gardens. Plenty of shadows, color and even some motion from the water.

Color me impressed.


One the left is one image from the bracketed exposure,
probably what would be a decent exposure without HDR.
On the left is the HDR image.
Image copyright Erik Markov 2009

To get an idea of the setting of this photo, the water fall runs from the west down the hill to the east, and it's 1:30pm when I took the bracketed series of images.

For the HDR image I took 7 bracketed images from 1/60 to 1/15 of a second at f16. In the image you can see a little bit of ghosting in the trees because it was so windy. I was impressed though with how little ghosting there was in the water, I think it still looks fairly natural and I was a little concerned about that.

Update- Forgot to add the file size of the finished photo. 33mb, and the 7 files I used for the image in Photomatix were 7-9mb each. That was full res on the camera with fine compression. I just got a new desktop pc with 2.4ghx Intel quad core chip running 3gb of RAM which I used to process the images and I didn't notice any real slow down. Took maybe 20 seconds or so for Photomatix to compile the images into one. I say this only in the interest of full disclosure, I'm not positive how the software might work on a computer with a slower processor or less RAM. There is a FAQ on HDRsoft's site that might be able to answer some of these questions.

I put both images side by side so that you can see how much I lost with the processed HDR image. There was a small band I cropped off. This occurs because the HDR software has to line up the image as best as possible for it look correct. And there are a ton of settings in the software I am using, Photomatix by HDRsoft. Given more time to play around with it, I might be able to adjust it to eliminate that band. Just to be on the safe side I would watch what was on the edges of my frame to make sure I wouldn't lose anything important. Shooting a little loose is a good rule of thumb.


An HDR image with 9 exposures.
Image copyright Erik Markov 2009


I've seen some HDR images that look really good, so good that you can't even tell sometimes it's an HDR image. I think that's what to strive for, if you can get it so that it looks as though the image is lit by some sort of magic light, you've done a good job. And I've seen some images that are obviously HDR because they have been so overworked.

The above image with the 9 exposures skirts the edge of being overworked I think. Particularly in the grass on the left side of the waterfall. Also on the right side, the rock wall at the bottom of the falls, there is a highlight on the top of the rock that, at least to me, seems to have too much detail in it. In the series of 7 exposures, the highlight gets a little blown out which I think makes the image look a little more natural.

I've only played around with it a little thus far, but it's enjoyable process. it takes some playing around to learn what works and what doesn't. I shot some flowers that didn't work well as HDR images. The day was extremely windy and a small object like the flowers were getting sent every which way, causing a lot of ghosting in the HDR image.

To do an HDR image that will turn out well without wasting your time, a tripod is a near necessity. At the very least, a sturdy place, such as a rock to rest your camera on. A remote trigger is also helpful, keeps you from disrupting the frame. Any slight movement of the camera is going to result in an image that could be less than what you hoped for. And HDR software to process the image. Photoshop includes an HDR processor in its latest version and there are several companies that make software.

The great thing with Photomatix is you can download it and try it out to see if you like it before paying for it. It runs $99 so it's not exactly cheap, but considering how powerful of a program it is, seems pretty reasonable to me. As you can see from my images I haven't purchased it yet because i still have the watermarking on them, but I plan to rectify that soon.

This is just a guess on my part, but I think as I play around with it, it will be a long learning process finding out what works for a good HDR image and what doesn't. Shooting the image is the easy part, just bracket your exposures and you're good to go. It's being able to see before shooting the images what is going to work well that is the difficult part. Don't want to waste time shooting several series of images, only to process it later and find out it looks like crap for whatever reason.

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