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Old Dec 12, 2002, 6:12 PM   #1
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Default white balance

Hi everyone
Complete beginer s602z. When and how do I decide that auto white balance will not suffice. Using the white paper to set the balance. What does it achieve. Sounds dumb, but I am lost
Rafael
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Old Dec 13, 2002, 7:30 AM   #2
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White balance is easy, just read the manual .. kit's exposure that loses me .... you seem to need to add more exposure when something is bright which makes no sence to me????
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Old Dec 13, 2002, 4:49 PM   #3
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Since nobody's offering, I'll do my bit in simple terms. White balance is necessary in electronic cameras, to achieve faithful rendition of colour on the final print, irrespective of the type of lighting used for the original scene. Film cam people put filters in front of the lense to do the same thing, or choose different film types.

Consider 2 extreme examples, tungsten electric light indoors. and daylight outdoors. Tungsten light is actually a yellow orange light, whereas daylight is more blue. Cams are not like human eyes - they are really pretty stupid. Without colour correction, your indoor pics would look orange, and your outdoor pics would look blue.

So what the cam does in auto white balance, is look for a white area illuminated by the light, and correct all the colours - so for printing, all the colours will look correct. If the cam doesn't do this well, photo editors can correct errors afterwards. Because the human eye is very clever, you see things under different lighting in 'normal' colour.

So, as well as auto white balance (which can take time in the cam to compute) you often find a setting for indoor tungsten colour balance and outdoor. Often the term 'colour temperature' is used. Tungsten lights are low temperature say 3200K, and daylight is higher 6500K and above. Your Xenon flash is matched to near daylight by the way -so you can use it for extra light outdoors.

In some cases your scene may have no white areas and the cams auto balance arithmetic may not give the right answer - on your lcd, the pic. may have a colour cast. So the trick is to pan your cam to a white area, half press the shutter to get it to work out the white balance, re-frame the shot then press the shutter full down.

Be carefull, not all white paper is pure white, it often has blue added, so your cam might get the calcs wrong with paper.

Personally,I zoom into the whites of human eyes in post editing and colour correct to that. We all have two eyes!

This is the simplified theory then. The problem comes when you have mixed lights such as daylight/flourescent/tungsten in the same scene. The auto white balance doesn't know what the hell to do. This is when your brain says ' most of my scene is say tungsten', so i'll manually fix my cams balance to this, then the auto won't get it so wrong.

Is this enough?
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Old Dec 14, 2002, 9:18 AM   #4
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Hi
Alfisti thanks for your input. Voxmagna-your in depth explanation has solved my problem. Thank you
Regards...Rafael
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Old Feb 4, 2003, 9:23 PM   #5
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Quote:
Originally Posted by voxmagna
Is this enough?
_______
Yes and no. Maybe you should discuss a little more about color temperature from 3200K (warmer color) up to 6000K (cooler color temp). Also the FinePix has a white balance compensation menu for shooting undr various lighting conditions, i.e., shade, fluorescent, incandescent light, blue sky. I'm not sure if there is such a thng as a white card (like a grayscale card ) available in photo shops.

For my part, I'll just use the WB (white balance setting on the camera) to adjust color temperature output.
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Old Feb 5, 2003, 4:41 AM   #6
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Quote:
Yes and no. Maybe you should discuss a little more about color temperature from 3200K (warmer color) up to 6000K (cooler color temp).
I could do, but then there has to be a balance between writing a book on a subject that can be quite complex, and providing sufficient help for members to dig deeper and help themselves if they want!

The cam makers provide auto and manual settings. Auto is generally for people who just want consistent average performance, manual presets benefit those who wish to exploit more flexibility whilst understanding what they are doing. In the latter case, it would be unfair to over simplify a subject which might result in poor pics - and white balance is like that. Most WB errors in auto can be improved in post. Shooting indoors when you might wish to force WB is generally only an option for studio work, since most cams have poor sensitivity with a 60W light bulb!

When you force WB, go out and forget it was set wrong, then you realise that worrying about it should be an exception - not messing with white cards everytime.

You can bracket several shots at different WB settings, quicker than you can optimise with white card. WB is not a precise science, mixed lighting screws everything - and often that's what you've got. The best advice here is to shoot with a stronger dominant known source which could be flash and crank up the shutter speed.

From previous experience with an older cam, white balance in auto becomes a problem in low light shooting because either the cams sensitivity is too low for the circuits to get it right or there is both low level and mixed lighting.
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Old Feb 5, 2003, 9:42 AM   #7
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Re: white Balance

Hi
Dennis, thanks for responding.
Voxmagna, as usual thank you for sharing your knowledge. Makes my learning process much easier and fruitful.

Warm regards....Rafael
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Old Apr 17, 2003, 11:35 PM   #8
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[ So the trick is to pan your cam to a white area, half press the shutter to get it to work out the white balance, re-frame the shot then press the shutter full down.
_____________________
On my 4900Z (and I assume the S602 works the same way), if I half depress the shutter release button while pointing to a white area --which may not be the subject matter if the subject matter has no whites-- then the focus and autoexposure is locked to the white area, not the subject matter. Wouldn't this throw things off?
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