HDR Imaging

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KingSmono

KingSmono

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So I know some of you guys are photography-nuts as well as flashaholics... Have any of you ever messed with HDR images? If you're not familiar with HDR imaging, it's where you take multiple exposures of the same picture, and combining them into 1 image. You can set up most high-end cameras to take the multiple exposures automatically by using Automatic Exposure Bracketing or AEB. Then you use a program like Photoshop or Photomatix to combine the multiple exposures and create the single HDR image.

Here is a cropped version of the original shot with normal exposure (0EV) taken on my Canon 40D.

LS27_Original_Crop.JPG



And here is a cropped version of the HDR image, comprised of 5 exposures (-4EV, -2EV, 0EV, 2EV, 4EV) also taken on my Canon 40D.

LS27_HDRl_Crop.JPG


In this example, the difference is very subtle, but soon I'm going to experiment with outdoor shots, where the HDR pics will stand out much more...

Do any of you guys have any HDR images or any experience with them? I'm trying to learn and get all the advice I can, because using the technique you can get some pretty cool results!
 
There is also a program called CHDK (Canon Hacker Development Kit, completely free) that can be loaded on the memory card for many models of Canon brand Point and Shoot cameras.

CHDK can automatically do bracketed shots for HDR.

There is also a support forum for CHDK--and many discussions about how to do HDR and some examples (information will work with any camera). Just put HDR in the search box.

-Bill

List of major features of CHDK software (does not change camera internal firmware--loaded from memory card each time camera is turned on).

  • RAW - CHDK can record raw files, giving you access to every bit of data the sensor saw, without compression or processing. Raw files can be manipulated on the camera, or processed on your PC. CHDK also has experimental support for the open DNG raw standard.
  • Override Camera parameters - Exposures from 64s to 1/60.000s with flash sync. Full manual or priority control over exposure, aperture, ISO and focus.
  • Bracketing - Bracketing is supported for exposure, aperture, ISO, and even focus.
  • Video Overrides - Control the quality or bitrate of video, or change it on the fly.
  • Scripting - Control CHDK and camera features using ubasic and LUA scripts. Enables time lapse, motion detection, advanced bracketing, and much more. Many user-written scripts are available on the forum and wiki.
  • Motion detection - Trigger exposure in response to motion, fast enough to catch lightning.
  • Edge overlay - Detect the edges in a scene, and display them later. Ideal for timelapses, stop-motion, stereography and much more.
  • Live Histogram - CHDK includes a customizable, live histogram display, like those typically found on more expensive cameras.
  • Zebra-Mode - Displays under and overexposure areas live on the screen.
  • GRIDS - Create custom grids and display whichever one suits your shooting conditions.
  • Multi-Lingual Interface - CHDK supports about 13 languages, and adding more languages is simple.
  • DOF Calculator - Display detailed DOF information on the screen.
  • Customizable OSD - Improved display of battery status, free space, camera parameters, and much more. Fully customizable with an on-screen editor.
  • Filebrowser - Manage files without a PC.
  • Textreader - Display text files on your camera.
  • Games - Play Reversi, Sokoban or 4-in-a-Row on your camera.
  • USB remote - Simple DIY remote allows you to control your camera remotely.
  • Benchmark - Compare the performance of your SD cards.
  • User Menu - Edit your own customizable User-Menu for fast access to often used features.
  • there is even more → read the Manual & explore this wiki.
Click to expand...
 
Oh wow, that's really interesting! I format my memory cards ON the camera (as opposed to on the PC), so I wonder if I assume I'd have to reload the CHDK software to the memory card every time, huh? I'll have to play around with it on my wife's Canon P&S.

I went down to a park nearby and brought my camera (Canon 40d) and tripod today... below you can see the original image, and the HDR image which is comprised of 5 AEB shots. When processing the HDR image, I was going for a more "dreamy" or "surreal" look. I'm very satisfied with how it came out!!

Original Image:
Bridge_Original_Resized.jpg


HDR Image:
Bridge_HDR_Resized.jpg
 
Yes, you would have to reload the CHDK software and any program scripts and setup/cfg settings you have saved if you reformat the card...

There is a small tool (for PC--search for "cardtricks") that automatically sets the "boot from card" flag and copies the software and files over--if you want. But, it is really as easy as MSDOS, a boot flag byte, and one .bin file (at a minimum) required...

And this is a case were having older models of Canon P&S cameras may be better for you--it takes a few months (at least--sometimes a year or more) for somebody (or gaggle of people) to download the code from the camera and develop the symbol table for the new CHDK software to hook into... So the newest cameras are not supported when they are first brought onto the market.

-Bill
 
IMO, HDR when done conservatively, can be fantastic looking. I think most HDR images are over cooked and it becomes more gaudy then appealing. To each his-her own though.

These are single exposures that were adjusted in Lightroom. It is on that verge and I quit massaging after getting them this far. A bit of color correction and gently adjusting the range a bit would bring it in. These were practice pieces to prove to myself it can be done with a single frame.

sansim1100b.jpg


gnysnst.jpg
 
Wow -- very interesting stuff !


Is there a "free", stand-alone program to convert

my bracketed images to HDR files ?


Don't wanna' use Adobe PhotoShop.

And don't wanna' hafta' buy anything else.

:broke:
_
 
I believe there is... Search the CHDK Forum for "HDR"... There should be several programs, as I recall, that you can download to run HDR... There are programs that also can stack depth of field shots and stitch multiple shots together too (may even be the same program in some cases).

Remember that the HDR program also must stitch/align the shots to prevent bluring.

The CHDK forum is pretty neat--a bit like CPF. Every thing Canon P&S camera and very family friendly (last time I was there a few months ago).

Laslty, if you you have a DSLR (or, to a degree, the Canons with CHDK installed)--you can use a Single RAW shot to get your data for HDR exposure manipulation... JPEG files are 8 bit deep, Canon P&S RAW file is around 10 bit, and DSLRs are around 14 bits deep. The RAW files can provide some real help in extracting shadows/highligts that JPEG mapping tends to drop.

-Bill
 
I wonder how this could be used to compose beamshots?

Anyone want to give it a shot? I know it may not be accurate representation of the beams, but it might create something spectacular...
 
Enzo Morocioli said:
I wonder how this could be used to compose beamshots?

Anyone want to give it a shot? I know it may not be accurate representation of the beams, but it might create something spectacular...
Click to expand...


Seems we had the same thought. :D
Some hours ago I created a thread about the beamshot question here:
http://www.candlepowerforums.com/vb/showthread.php?p=2750672#post2750672

We can continue this discussion there in order to avoid disturbing this thread here. If anyone has anything to contribute at all.

bernie
 
Man I'm glad I saw this thread. I bought my wife an A590 for Christmas. Looks like CHDK adds a lot of awesome features. If I can't get the camera away from her I might have to get my own just to play with!

Those images look awesome, btw.
 
A few of mine:
9542perspec.jpg


better810w.jpg





A few that were a bit big to directly post:

This was actually shot with a fisheye, I think I did a decent job of correcting out most of the distortion and made the building somewhat correct.

7 shot bracket:
 
I wanna say it was a Volvo 1800 on the right (with some sort of big block being shoehorned in, and the other was a Shelby of some sort if I recall...We were there to photograph the cars that my back was to in that shot.
 
I just got a decent enough camera that I can start dabbling in HDR. Here's my first ever attempt.

3135172032_dc0c33a0f8_b.jpg


I like the concept, but there is too much light detail -- IE the lights are very bright. I'd rather have less light detail (Like from my shot that was underexposed, so you can see the individual detail of the lights) and then have the rest the details filled in. I think that would make the image look more natural. I'm not sure how to accomplish that though. I guess one way, if you can control the light source of course, would be to turn some of the lights off in your overexposed photos. In this case I could take the over-exposed photos with the tree-lights turned off.
 
I think it looks good the way you did it. :) For the tree, I was thinking shoot a dead on exposure without the lights on then do the - bracket with the lights on.
 
Just have to be put back. The kids can enjoy a double Christmas but they will already know what's under the wrapping. ;)
 
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