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amish
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Joined: 11 Apr 2006
Posts: 1433
Location: Outside Philadelphia

PostPosted: Thu Feb 10, 2011 8:46 am    Post subject: HDR Photography?? Reply with quote

I have recently, well as of 30 minutes ago discovered HDR photography.

Quote:
A HDR photo is a sandwich of three photos, one shot with the default exposure; one underexposed by two f/stops, meaning it gets one-quarter as much light; and one overexposed by two f/stops, meaning it gets four times as much light.


I am curious if anyone here has done this and could recommend some type of freeware for combining images to create this effect.

Here is a great link to some wonderful shots:
http://www.thatindiedude.com/2008/10/inspired-3-hdr-photos-flickr/

Thanks!

Tom
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andy
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Joined: 01 Nov 2006
Posts: 6237
Location: Rochester, NY

PostPosted: Thu Feb 10, 2011 4:12 pm    Post subject: Reply with quote

That is some pretty cool stuff. Makes it look like an illustration. Cool effect. I know nothing about it other than that.

My guess would be that you would have to use photoshop to combine the exposures, and would also have to take the photos in rapid succession to minimise movement issues between the separate exposures. If you just combine the exposures the lightest areas would wash out. You might have to manually separate the areas and combine them over the top of the darkest as the base, filling in the darkest areas a part at a time. maybe even just overlaying two areas at a time with the lighter actually in the back, and just erasing parts of the dark top layer by hand where you want it to lighten up. Flatten the two images together, and then repeating with the third lightest image in back.

Just some guessing, based on how I would try it, but if there is a computer program to automatically do it, that would be cool too.

Andy
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TM
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Joined: 06 Mar 2009
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PostPosted: Thu Feb 10, 2011 11:09 pm    Post subject: Reply with quote

I do a fair amount of High Dynamic Range photography, primarily real estate and architectural.

HDR is useful because both film and digital cameras can not capture the full range of black-to-white that the human eye can. The best example is being inside a room with large sun-lit windows. Sitting inside the room your eyes automatically adjust to the light intensity differences between the inside and out. Inside being illuminated with rather dim incandescent lamps, outside with the bright dun.

If you shoot a photograph of that scene you normally have three choices. First is the “automatic exposure”, where the camera chooses some average exposure. This exposes everything as “average”, so the outside sunlit areas will be overexposed (too bright) and the shadow areas inside will be underexposed (too dark). You could alternatively expose for the bright outdoors, leaving the interior too dark. Or you could expose for the darker interior, causing the bright interior to be way too bright.

No good way of dealing with this in a single exposure. What you do in HDR is to shoot multiple exposures of the same shot. One “average”; one exposed for the bright outdoors; and one exposed for the darker interior. Then, using either Adobe Photoshop, or better yet Photomatix Pro, the software combines the exposures to create one unified exposure. This creates a final image which more captures the dynamic range of the eye. And ideally the exposure of inside and out becomes seamless.

Photoshop has a way of doing this with a single exposure. Photoshop fabricates the over- and under-exposed images and makes an artificial HDR shot. I don’t think that works well.

You can shoot as many exposures as you want, and then combine them. With my old Canon 20D I could set it for three bracketed exposures. So I just put the camera on the tripod and only had to just hit the shutter button three times. With my Canon 1Ds I do five exposures. I can set it to seven exposures, but I don’t see much, if any improvement.

Then I combine them in Photomatix, which most consider to be better than Photoshop for this. There are many ways to then alter the image in a non-realistic way in Photomatix, for those who are looking for visual effects. But since I’m mostly shooting architecture, I’m looking for a realistic result, and haven’t explored that much.

Here’s a link to Photomatix: http://www.hdrsoft.com/

Tony
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jfuste
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Joined: 31 Dec 2007
Posts: 739
Location: Barcelona, Spain

PostPosted: Fri Feb 11, 2011 3:50 am    Post subject: Reply with quote

TM wrote:

You can shoot as many exposures as you want, and then combine them. With my old Canon 20D I could set it for three bracketed exposures. So I just put the camera on the tripod and only had to just hit the shutter button three times. With my Canon 1Ds I do five exposures. I can set it to seven exposures, but I don’t see much, if any improvement.


You are right man! I'm using now a EOS 7D and the 3 exposures in bracketed mode are done with one hit! A good improvement. And as you said, the right way to do any HDR shot is with tripod and remote control (infrarred or radio better than cable based one) to avoid movement at all.

Photoshop is a great piece of software to do this kind of things, to fake it, or to enhance it. I'm using it from the very first version (2.5Beta in PC I guess), but they are some nice free apps around for any platform. A nice feature of the new iPhone 4 is the ability to make an HDR picture with one shot... Not so great as I would, but easy and automatic! Results varies, of course.

The best shots in HDR includes skies and so on. The high contrast in the sky add a great amount of drama. People portraits, in the other side, are not so suitable IMHO, if you don't need some artistic finish.

Last, best results are achieved in RAW format instead JPG. RAW captures much more information (exposure, etc) and post-process offers more choices.

Som nice FX can be done, out of HDR itself, with an action pack for Photoshop called Nill Photo FX. Fake HDR, Vogue effect (I love it!), infrarred, sepia, old timer, vivid colors.... Take a look here:

http://www.nill.cz/index.php?set=effect

Sample:




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sethb6025
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Joined: 22 Dec 2006
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Location: York, PA US

PostPosted: Mon Feb 14, 2011 6:09 pm    Post subject: Reply with quote

This looks neat. There is a bracket function on my camera so I'm going to take a few exposures and run them through the trial of Photomatix.
Thanks Amish for bringing it up, and thanks Jfuste for the software link!
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