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Great kludwig20 2006-05-25 12:06

Quite impressive structure. Pretty difficult shot as far as finding the proper exposure. In my opinion it may be slightly over exposed actually. I like your vertical composition it works well here, I think the image could use a 1 degree ccw rotation. I think to truely portray it's beauty it would take either a film camera or five exposures merged to a HDR image to capture an acceptable dynamic range. Provided of course you had a tripod available. Either way good result, the highlights just seem a little overwhelming.

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Old 05-25-2006, 10:15 PM
babri babri is offline
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Default To kludwig20: Guide me

Hi Kirk,
Thanks for your perfect critique. I am a begginer and like to know more about the method you suggested. Could you introduce me some references about HDR image and merging procedure?
Thanks again. Stay well,
Reza
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Old 05-25-2006, 10:38 PM
kludwig20 kludwig20 is offline
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Default Re: To kludwig20: Guide me

Merging to create an HDR would require either a copy of photoshop cs2 or photogenics. There may be other comparable programs capable of merging images. Of the two programs listed I would recommend PS CS2 as it seems to give a better final result from my experience.

To get started with this procedure, a little pre-planning is necessary. One must recognize the presence of a great photograph and that it has so much contrast that a normal exposure could not render a satisfactory image or print. Once the subject is identified set up the camera, cable release and tripod combination and compose the image. The cable release and tripod are important, since the group of pictures must match exactly. In creating the exposure the set, the shutter speed is the only control that may be varied! If the f/stop is varied, depth of field and image bloom size will be altered and the images and they will not match precisely. Be certain to use shutter speed alterations only. The image set should include one image with the highlights over-exposed followed by a group for which the exposure has been reduced, one stop at a time, up to nine exposures. The final exposure should have dark or even under-exposed blacks.

Upon returning to the computer, the camera data image files are down loaded to the computer in your normal manner. The selected image set is then moved to a new and specific folder for the HDR merge treatment. See Figure 1. Next Photoshop CS2 is opened and the procedure begins. Note, HDR may also be initiated from the Bridge software if you are working with RAW files. With regular files, go to File > Automate > Merge to HDR and click. The dialog box will request that you browse or identify the file folder containing two or more files to be HDR merged. After the file selections are made, click OK. Each of the files open in CS2 and a large composite image is shown. There is only one slider adjustment available at this point. Adjust the slider until the highlight values of the image look best for your application and then select either 8-bit, 16-bit, or 32-bit output and click OK (I would recommend selecting and saving the original HDR copy in 32-bit to save the widest dynamic range.) The image can can be be downconverted to a standard 8-bit image after the fact and it seems to retain a much better dynamic range. You would also need to convert it down if you plan on doing any major post processing otherwise your options in photoshop will be dramatically reduced. Another image pops up in a new dialog box and allows another set of selections to be made. The Highlight Compression selection is the most automatic of those shown. The Exposure and Gamma selection allows additional highlight and mid-tone adjustments, respectively. The Equalize Histogram selection allows full manual adjustments to be made via a curves style dialog box. There is as much control available to creating the final image, as you want to be involved with. With all adjustments made, click OK. The speed at which all of this high-powered computing takes place will be dependant upon your computer and may take a few seconds to a few minutes to accomplish the task.

Your image here would be a perfect candidate for this type of work. These HDR images are really not an option if anything in the frame has moved between exposures. Typically what works best for me is to find my proper exposure and shoot one picture. I then take take 4 more shots, 2 of them underexposed bracketing by 1 stop each and 2 of them overexposed bracketing by 1 stop also. So if my ideal exposure was lets say 1/60th of a second I would have five shots:

1/250
1/125
1/60
1/30
1/15

You then merge them with photoshop or other capable programs. Hope this helps feel free to contact me if you have any questions. I'm still experimenting with these HDR images and have come up with some pretty good results. It is astonishing how much difference it can make. However a tripod is a must and remote shutter release is a plus.
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Old 05-25-2006, 11:03 PM
kludwig20 kludwig20 is offline
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Default Re: To kludwig20: Guide me

A visual example can be found here:

http://en.wikipedia.org/wiki/Image:HDRI-Example.jpg

Sorry I don't know how to link but it appears they take the variances to more extemes varying from 1/40th to 25 seconds. I guess it all depends on the environment and lighting.
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Old 05-26-2006, 02:17 AM
babri babri is offline
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Default Re: To kludwig20: Guide me

I reviewed the example. It looks great! I had not heared about "High dynamic range" before but I now completely got it from your note, Kirk.
I am being tempted to test it. I should find an opportunity to photograph. Thanks for your useful guide. With Kind Regards.
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