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Walter Susor
White Crane
Username: wsus

Post Number: 1814
Registered: 08-2003
Posted From: adsl-75-6-241-208.dsl.pltn13.sbcglobal.net
Posted on Sunday, August 22, 2010 - 03:15 am:   Edit Post Delete Post View Post/Check IP    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

http://www.dpfwiw.com/exposure.htm
This is an excellent treatise on digital photography with emphasis on obtaining well exposed, color corrected photos. The article is comprehensive and readable. The information presented should be especially useful to someone who is making the transition from film to digital. Many of the remarks are referenced to the author's 2 megapixel Olympus camera but also apply to todays 10 MP and higher cameras (my camera is 5 MP and I found this article very informative) The author has also attached links to additional reading.

Here is a sample from the section on outdoor light variations.

Sunlight Variations

Most of the variations observed in the color of sunlight at the Earth's surface stem from spectral variations in atmospheric scattering. In clear air, short (UV-A and blue) wavelengths suffer up to 16 times more scattering than longer (red and near IR) wavelengths because scattering efficiency by air molecules (N2, O2, CO2, etc.) varies inversely with the fourth power of wavelength.

Direct sunlight here on Earth is yellower (redder and greener) than the light leaving the sun because the atmosphere scatters a good bit of the blue away before the light ever reaches you and your subject. (Yes, some of the scattered blue will eventually scatter back to the surface, but there's still a net loss of blue.)

Overcast light is bluer than direct sunlight because visible wavelengths are all scattered equally well by particles the size of condensed water droplets in clouds—hence clouds in shades of gray at midday. Scattered blue light falling onto the cloud tops from above gets tossed back in the mix, now with an even chance of getting to the ground. There's still a net loss of blue, but under overcast skies, it's smaller relative to losses at other wavelengths.

Outdoors, shaded areas are illuminated predominantly by skylight, which is quite blue on sunny days and closer to neutral on overcast days. Shaded spots under leafy trees can also pick up extra green light reflected from or transmitted through overhead leaves.

In the morning and evening, sunlight takes a much longer path through the atmosphere, losing even more blue and some green to scattering along the way. That's why early and late day sun is redder, and why sunrises and sunsets feature the warm longwave (red, orange and yellow) colors we so admire.


Walter
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Arno Jacobs
White Crane
Username: jcbs

Post Number: 3395
Registered: 07-2004
Posted From: ip4da26c4f.direct-adsl.nl
Posted on Sunday, August 22, 2010 - 10:22 am:   Edit Post Delete Post View Post/Check IP    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Thank you Walter, a very nice link to understand photography.

Kind regards,
Arno
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Julian Chen
Peacock
Username: jlchen

Post Number: 473
Registered: 09-2003
Posted From: 119.97.231.158
Posted on Saturday, November 20, 2010 - 02:16 pm:   Edit Post Delete Post View Post/Check IP    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Hi Walter,

Thank you for sharing the wonderful web site.

Regards,

Julian
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Joan K. Brand-Landkamer
White Crane
Username: fnoirelover

Post Number: 3818
Registered: 10-2005
Posted From: h137.228.16.98.dynamic.ip.windstream.net
Posted on Monday, December 03, 2012 - 01:51 am:   Edit Post Delete Post View Post/Check IP    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Dear Walter, I am ashamed that I remember so little about putting pictures into Gotheborg.com. My first rather stupid question will get me at least taking pictures with my older olympus....."Do you have to take the right size picture in the first place to smoothly place them in
gotheborg.com? 800 by 1.25? The camera is a 4.0 megapixel,digital camera c-765 ultra zoom. I want to keep using it. Years ago, I tried with help to place pictures in my posts. They were smaller but clear. I have so many mysteries to share. Walter,if you could answer this first question and give me the link to the easiest ABC method to teach me like 'FOR DUMMIES',Sorry,new computor,no mouse. Husband in hospital with a broken pelvus. Home soon. Joan
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Walter Susor
White Crane
Username: wsus

Post Number: 2578
Registered: 08-2003
Posted From: adsl-75-6-225-245.dsl.pltn13.sbcglobal.net
Posted on Monday, December 03, 2012 - 04:00 am:   Edit Post Delete Post View Post/Check IP    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Hi Joan,

I am so sorry to learn of Leo's injury. I hope recovers soon. I'm currently grounded from hip surgery but hope to be back in service by Christmas.

I'll try to guide you with your photos the best that I can. I have always used Macs and do not know windows which I presume you have. By the way, all of my photos have been enlarged from a portion of the field from an old 5Mp Nikon so your 4 Mp camera should be just fine.

1. Always use a tripod with your camera. This can't be overemphasized.

2. The light source is not critical if your camera has basic adjustments like white balance and variable exposure setting. If you do not have a neutral grey target to set the white balance, take several trial exposures, setting the white balance to the different preset camera settings, and, using the custom white balance setting, to different shades of white or grey paper, then use the setting that results in the most natural colors.

3. The first shot of the piece should be from 4 to 6 feet away and cropped so that we can see the piece overall from a normal viewing distance.

4. Don't forget to use the camera's macro setting for closeups. Check your camera's manual for the minimum focus distance with the macro setting. If you do not have the camera manual, you can always find it on the manufactures web site.

5. Before your photo is resizesd, you will need to crop the image to highlight the features that you want to show, Here is a link to a free crop program for windows that I found with a duckduckgo.com search: http://www.topdrawerdownloads.com/download/104855
Here is a free on-line service that will both crop and resize photos:http://www.resizr.com/

6. You can resize your photos with free programs like freePhotoConverter, iResizer.app (Mac), gimp ( a free Photoshop substitute, somewhat difficult to use}, and others. Here are step-by-step directions to resize the photo using a number of photo programs that you might have on your windows computer: http://www.wikihow.com/Resize-Digital-Photos

This is probably more than you want, but it may be of help to new members who are having difficulty preparing and uploading good photos.

Best Regards, Walter
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Joan K. Brand-Landkamer
White Crane
Username: fnoirelover

Post Number: 3819
Registered: 10-2005
Posted From: h137.228.16.98.dynamic.ip.windstream.net
Posted on Monday, December 03, 2012 - 05:05 am:   Edit Post Delete Post View Post/Check IP    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Dear Walter,such good advise! Get a Manual!!! Yes! I bought a nice little setup( ebay) with a tripod and little stage with a light on either side years ago. I don't know my camera, that comes first! Many Many thanks to get me started! Hello to Rosie! Hello to dear friend who lost his son,named Vietnam!... What a Tragedy!!! Warmest regards, I love Gotheborg.com!!! I think it keeps me grounded!!!
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Joan K. Brand-Landkamer
White Crane
Username: fnoirelover

Post Number: 3820
Registered: 10-2005
Posted From: h137.228.16.98.dynamic.ip.windstream.net
Posted on Monday, December 03, 2012 - 05:15 am:   Edit Post Delete Post View Post/Check IP    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Dear Walter,Sorry about your hip!I hope you will be able to get around ok. warmest regards, Joan and Leo

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