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singhal2
09-03-2004, 07:56 AM
most digital cams have "white balance" in their menu and this has further options ....what does it mean, do we have to actually white balance the cam everytime we click and if so how,is the digital cam like the fibreoptic endoscopes used in medicine which need to be white balanced everytime we use them
thanx
singhal2

Rhys
09-03-2004, 08:02 AM
most digital cams have "white balance" in their menu and this has further options ....what does it mean, do we have to actually white balance the cam everytime we click and if so how,is the digital cam like the fibreoptic endoscopes used in medicine which need to be white balanced everytime we use them
thanx
singhal2

Generally, white balance is best left to automatic. There are occasions - photographing snow or desert scenes, however, when it might be best to select a specific white-balance. Also, when photographing an intereor which is illuminated by a mixture of artificial light and daylight, it might be necessary to select daylight or artificial light balance depending on the required effect. Most of the time, colour balance can be changed on the computer afterwards anyway. I'd say that white balance isn't that useful.

jaykinghorn
09-03-2004, 10:01 AM
Generally, white balance is best left to automatic. There are occasions - photographing snow or desert scenes, however, when it might be best to select a specific white-balance. Also, when photographing an intereor which is illuminated by a mixture of artificial light and daylight, it might be necessary to select daylight or artificial light balance depending on the required effect. Most of the time, colour balance can be changed on the computer afterwards anyway. I'd say that white balance isn't that useful.

Rhys, I would have to respectfully disagree that white balance isn't that useful. The white balance setting on your digital camera allows you to specify the color of white. The correlated color temperature, usually expressed in degrees Kelvin, when set correctly minimizes the amount of work you need to do to the file in post production. While you are correct in stating that the color balance can be changed on the computer afterwards, this applies to RAW camera files only. If you are shooting JPEG, it is very important that you set the white balance correctly. Major adjustments to compensate for an inaccurate white balance, say, image shot under tungsten lights with daylight WB have a tendency to compress some color relationships making it difficult to achieve satisfactory colors throughout the image.

I don't have any experience with fibrescopic endoscopes, but I would predict that the software needs to perform a white balance check to ensure that it renders colors accurately.

Best regards,

Jay Kinghorn
RGB Imaging

singhal2
09-03-2004, 01:31 PM
thanx jay and rhys,what i understand is that white balance IS important,so how does one do it,i read somewhere about shooting a grey card/white card,but how does that help white balancing,i being a doctor who works with fibrescopes daily do white balance on my scopes,by keeping a white paper/gauze piece in front of the camera and pressing the white balance switch on the scope/camera the camera then adjusts the white balance automatically,how does a digital camera achieve this?
thanx
singhal2

Jeff Keller
09-03-2004, 01:59 PM
thanx jay and rhys,what i understand is that white balance IS important,so how does one do it,i read somewhere about shooting a grey card/white card,but how does that help white balancing,i being a doctor who works with fibrescopes daily do white balance on my scopes,by keeping a white paper/gauze piece in front of the camera and pressing the white balance switch on the scope/camera the camera then adjusts the white balance automatically,how does a digital camera achieve this?
thanx
singhal2

Just about the only time that I need to use custoom white balance is when shooting my test shots under my quartz studio lamps. For everything else, auto white balance works about 90% of the time. Indoors can be tricky, but switching to the tungsten setting usually helps.

John_Reed
09-03-2004, 03:36 PM
thanx jay and rhys,what i understand is that white balance IS important,so how does one do it,i read somewhere about shooting a grey card/white card,but how does that help white balancing,i being a doctor who works with fibrescopes daily do white balance on my scopes,by keeping a white paper/gauze piece in front of the camera and pressing the white balance switch on the scope/camera the camera then adjusts the white balance automatically,how does a digital camera achieve this?
thanx
singhal2I think that's your question, right? The procedure varies for different cameras, but generally involves setting (through a menu) the camera to "Manual WB", and the next step is usually to aim the camera at a white card illuminated by the lighting you're balancing against, and squeezing the shutter. When I'm doing this for my FZ10, I usually zoom in first so that the white object (I've done it on someone's white shirt before) fills the screen before I start the balancing procedure. But, you don't have to keep doing it. It will retain that setting until you change it again, even if you turn the camera off and on. This has been my experience on both Panasonic and Nikon CoolPix cameras, maybe other cameras behave differently, I can't speak for the masses. I do use manual WB settings a lot when I'm shooting inside; just trust it more than "Tungsten" setting. Outside, it's Auto WB for me.