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Reducing Clipped Highlights w/ Digicams (Coolpix5000 Specifi


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#1 james

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Posted 22 April 2002 - 08:25 AM

For all the folks on this board who are soon going to jump in the water with your CP5000, I found an excellent article on reducing Clipped Highlights in the camera. The CP5000 is a "consumer" level camera, so it doesn't have the dynamic range that we see in Eric Cheng or Jim Watt's D30/D60 photos.

Because the camera has a lower dynamic range, we can see problems when shooting up towards the sun, or when shooting fish/critters with white on them. Here are a couple of examples:

image
Notice how the "sunball" goes from deep blue to white in only a few tones. Part of that could be your monitor settings and video card, but part of it is the limited dynamic range of the camera's CCD.

Here's another:
image
Notice how the Amberjack's "chin" is blown out white.

Don't despair! Those shots were some of the first out of the camera, and they use Auto white balance and the camera's "stock" settings for contrast and such. This article discusses how to improve on the stock settings to return some highlights and dynamic range to your photos:

http://www.vincentbo...stogram_pix.asp

Credit goes to Vincent Bockaert for the excellent article.

Cheers
James Wiseman
Canon 1DsMkIII - Seacam Housing
Dual Ikelite Strobes
Photo site - www.reefpix.org

#2 bobjarman

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Posted 23 April 2002 - 05:08 AM

Great Post, thanks for sharing it.

Funny, I was just about to post a thread on this same topic in more generic terms. I got some questions on digital imaging last week from some members of my camera club who were concerned that they couldnt seem to get a decent shot without blowing out the highlights.

We look at our camera manuals and the histograms in the examples are almost always perfect bell curves. Ever notice how real life it is virtually impossible to get a histogram that looks close to what the instruction manual shows? :)

In the year that I have been shooting digital on land, I have learned to almost always aim for a histogram that tilts to the left (underexposure). Shadows are easily recovered in PS through levels or contrast masking, but blown highlights are virtually impossible. Hence, as opposed to traditional film guidelines of shooting for 18% gray, I almost always underexpose between 1/3 and one stop.

DP review has an excellent thread on this topic as well:

http://www.dpreview....message=2580958

One of the things that I truly believe is an issue in digital imaging, is the mistaken belief that a shot taken with a digital can be uploaded and posted. IMO the best lesson one can learn from digital, is that it really takes more time than film to get a great image.......and you must become adept with a good image editing program such as PS. I am not talking about radically altering an image, but rather, learning and understanding curves, contrast, hue, saturation, and level adjustments. It's the total process of composition, knowing your camera, and post image processing that makes digital photographs wall bangers.

My 2 cents!

Bob

#3 SharpDiver

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Posted 23 April 2002 - 05:40 AM

I just took an all day Photoshop class a few weeks ago. I was totally blown away by what I didn't know about a program I have been using for years.

I bought several books from the seminar producers and am reading and practicing now. Most of the first book I am reading is aimed at preparing images for process printing, yet there are tricks for color correction there that I would never have tried.

One that I am particularly thrilled with that I will pass along to the rest of the PS junkies...

Convert an image from RGB to CMYK.

Use Unsharp Mask on the black plate. Set a moderate threshold, a fairly large radius, and a large amount (300 - 500).

Do the same thing to the weakest color in the image (often magenta in UW photos).

Look at the results. You can often get much sharper images than if you do an USM to the entire image. You can also combine this affect by now doing a very conservative USM to the entire image.

Something to try....

As Bob said, post-processing is an important element of the hobby we have all adopted.

#4 james

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Posted 23 April 2002 - 06:07 AM

Yep and Yep,

One suggestion for Eric would be something similiar to what they have over at robgalbraith.com: a "Photoshop to Prepress" forum.

I put together a selection of my photos in one of those divided picture frames this year as a Christmas gift to my parents. I was wondering why what I was seeing on my monitor wasn't what I was seeing on my glossy photo paper...:)

So I learned about Adobe Gamma (for my monitor) and printer profiles...oh what fun!

I agree with Jeff - most people only use about 20% of Photoshop's capabilities. I know that's about what I use.

This is certainly an interesting discussion. It's sort of running parallel to some of the discussion on the uw-photo listserv.

Cheers
James
Canon 1DsMkIII - Seacam Housing
Dual Ikelite Strobes
Photo site - www.reefpix.org

#5 snoack

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Posted 23 April 2002 - 01:56 PM

I was inspired by that idea and played around a bit.

Did you ever try to apply the USM to a copied level of the original set to a lower transparency ?

View results at http://www.dive.snoa...gitips/usm.html

Loading the page might take some time, because compressing the pictures would have destroyed the USM effects. Sorry.

Sabine

BTW: This post should finaly make me a lionfish :)

#6 SharpDiver

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Posted 23 April 2002 - 03:10 PM

just passing along things I've read.

The method you mentioned is also used in the book I am reading.

FYI: The book is "Professional Photoshop" by Dan Margulis. He was a Madison Avenue art director before he started teaching Photoshop. You would love it if you like to experiment and if you like to get the most from your images.