Showing posts with label High Dynamic Range. Show all posts
Showing posts with label High Dynamic Range. Show all posts

Monday, February 1, 2010

HRD #3 - High Dynamic Range Underwater

High Dynamic Range (HDR) is a hot new technique as we have written about before (Click Here for the first article). However, I have never seen one done Underwater. Here is what I think is one of the first ever true HDR photographs taken underwater. It is the Fire Engine in Dutch Springs Pennsylvania.


It is the product of three photographs, one underexposed by two stops, a "correct" average exposure, and one overexposed by two stops. The exagerated illustrative effect is enhanced by using PHOTOMATIX Software. Photomatix is a Photoshop plugin that is designed to do "tonemapping" with an HRD image. There is a the second post on HDR here you can use to review the exact Photomatix settings.


You can theoretically do HDR handheld, but you should use a tripod for best results. The software will be attempting to line up the three images you are generating. Any position variation will produce blurs. I use an SLR GorillaPod screwed into the bottom of my housing STROBE ARM TRAY. The GorillaPod is mostly non-corrosive except for the mounting screw. If your housing does not have a tripod screw, you may need to do some Jury Rigging here as I needed to drill a hole in the housing STROBE ARM TRAY and machine the threads using a Tap & Die. SERIOUS NOTE: I DID NOT DRILL A HOLE IN THE HOUSING!

Click here to see a larger version of the Fire Truck and more HDR.

Want an SLR GorillaPod? Click Here.
.

Friday, December 4, 2009

HDR #2 - High Dynamic Range - Using Photomatix Pro

There are different versions of Photomatix, but this post is designed to give you an idea of the controls you can use to effect an illustrative effect that the plug-in is capable of producing.

Rule #1 for Photomatix is don't be afraid to "play."

I like to use the dashboard more or less in order, starting at the top and working down. Be bold with changing settings to experiment.

Strength On the dashboard of controls, you will get the biggest "bang for the buck" by starting with Strength at 100%. It will give the most photo illustrative effect. The lower you go, the more photo-real it will appear.

Saturation at 100 is more Illustrative. At low settings, you can produce B&W.

Set Luminosity at 10 to begin and adjust from there.

Light Smoothing has five radio button settings. I usually like the second button. Experiment.

Microcontrast settings are a matter of taste and small adjustments count for large swings.

The remaining controls will have a less dramatic impact on the image but experiment to see what you like. Below is the product of combining the seven exposures and using Photomatix Pro.



Click here to see a larger version of this photo and more HDR.

Sunday, November 22, 2009

HDR#1 - SHOOTING HIGH DYNAMIC RANGE (HDR)


HDR using PHOTOMATIX PRO (above)


Straight HDR from Photoshop CS4


"Best Normal Exposure" from the series. Non-HDR.

NOTE: This is an introductory article, not a comprehensive how-to with all the possible permutations. The best HDR effects also uses a Photoshop Plugin called Photomatix from HDRSoft. HDR with Photomatix or Photomatix Pro requires some patience fiddling with new software, and a willingness to learn a whole new dashboard of controls.

HIGH DYNAMIC RANGE (HDR) photography is a relatively new technique that is in demand. It can be simply photographic with added detail or illustrative with an exaggerated look. Ever since Ansel Adams worked with the Zone system in film days, we have been trying to force the camera be able to deal with the extended brightness range that our eyes can see. We can adapt to an 11 f/stop range while the best digital cameras can see about 5 f/stops. It still amuses me when people say they only want "what the camera saw." How limiting when they saw so much more. So what to do? Plan ahead and shoot with HDR in mind.

HDR requires Photoshop CS2 or better. I am using CS4. As of this writing it is not available in Photoshop Elements. HRD software may be available as a plugin or other standalone.

The technique works best with still life subjects or scenes without too much movement. The reason is that you are making at least three or more different exposures and allowing Photoshop to "stitch together" the tones. Too much motion beyond a waterfall may get totally lost. Set your camera to shoot in APERATURE PRIORITY mode.

Aperature priority is needed so the focus and depth of field does not change. You start with underexposure of at least two stops, normal and at least two stops overexposure. You can shoot additional exposures beyond the two stop range as well.

You can also set your camera to do this automatically by setting it to Auto Exposure Bracketing, (AEB in Canon cameras that have the feature). Drive mode should be Continuous Shooting, not One Shot. You need to shoot at least three to seven shots of different exposures. Get to be best friend with your camera manual.

Find a nice location that has lots of highlights and deep shadows. Set your camera on a tripod begin your exposure series. See my HDR gallery for examples.

When you are back at the computer after you download, identify the range of files you shot. Ideally you shot a minimum of three shots, perhaps more with different exposures. Start Photoshop and find the files using FILE > AUTOMATE > MERGE TO HDR. Allow time for processing, perhaps a few minutes and you will get the photo in the middle above. Nice but not startling.

If you want the illustrative effect from Photomatix seen in the top photo, you need to get the plugin or standalone program. Prices start at about $100 US and go up from there depending on version and bells and whistles. See http://www.hdrsoft.com/ for more info on what is best for you. For my version, I first load Photomatix Pro, then select the files from there. More on Photomatix in another post.

Click here to see more of my HDR work.