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kevanrobitaille
Dec 8, 2006, 3:14 AM
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Ok, so. Im just learning photography so advanced apologies is this is a stupid question.
With a digital SLR, IE, Nikon D70s, if I meter off of something, in natural light, on an overcast day, decide it is a light tone, compensate by 1.5 positive stops, do I still need to worry about the white balance? In short, when compensating for tonal differences with exposure comp, how does the white balance effect the shot?
Normally I would just go experiment and figure it out. But I don't have the time to do so before my next trip. Thanks.
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trenchdigger
Dec 8, 2006, 3:40 AM
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Metering/exposure compensation controls the exposure of the shot, or how light/dark it is. It has nothing to do with color. The meter measures the brightness of the scene and sets the shutter speed and/or aperture to the proper setting to achieve an average of medium (18%) grey in the metered area. Exposure compensation produces a deviation in whichever direction you choose, letting either more or less light hit the sensor and therefore lightening or darkening the scene.
White balance is the camera's attempt to process the data it receives and make the color in the photo look natural. Most cameras will have an automatic setting and some menagerie of other settings possibly including sun, shade, clouds, tungsten light, and flourescent light. And then there's the most useful setting - custom white balance.
Read your manual and play with your camera at home before your trip to learn what each of these settings do. If you don't want to screw up too bad, keep the white balance on auto and exposure compensation near zero. Odds are the camera will be smart enough to take some excellent photos.
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dobson
Dec 8, 2006, 4:03 AM
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Trenchgger is exactly right. I will add that if you shoot RAW, the WB is meaningless because it is determined later in the computer software. I usually shoot with auto WB and adjust in my RAW processor to taste.
If you are bumping the exposure comp up, (which I usually recommend), you need to keep a close eye on the histogram to ensure that you aren't clipping the highlights. It's easy to screw up, and you can never recover the clipped data.
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trenchdigger
Dec 8, 2006, 4:19 AM
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dobson wrote: If you are bumping the exposure comp up, (which I usually recommend)...
Interesting, I find that I prefer most of my climbing shots underexposed by ~2/3 stop... To each his own.
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neuroshock
Dec 8, 2006, 4:28 AM
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trenchdigger is correct. i'd just like to illustrate whitebalance, to give kevanrobitaille a visual example.
i've thought of it as correction of color-cast. i typically take 1 shot per area (or change of lighting) of my greycard and then apply it later, digitally. i shoot RAW on AWB.
the wb_pre.JPG shows the shot taken with AWB. now, we know that grass is green and the pavement is likely grey, but the camera knows no such thing. it captures what it sees; in this case an orange tint. taking capturing a grey card gives the camera/software a reference point of reliably 18% grey. the software will figure out what adjustments need to be made between what it "sees" and what it "knows" and can apply that to the images taken. the wb_post.JPG is the result of such a correction having been applied. now the colors resemble what they actually are.
now, i might actually want that orange tint caused by early morning light for warmth. however, in several of my climbing shots i tend to get an unwanted greenish cast due to light reflecting off of the surrounding tree canopy. i use my grey card for white balance correction to accurately neutralize that and then apply any additional changes i desire afterward.
-mike
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Attachments:
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wb_pre.JPG
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wb_post.JPG
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neuroshock
Dec 8, 2006, 4:41 AM
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trenchdigger wrote: dobson wrote: If you are bumping the exposure comp up, (which I usually recommend)... Interesting, I find that I prefer most of my climbing shots underexposed by ~2/3 stop... To each his own.
agreed. if anything, i tend to underexpose 1/3-2/3 of a stop so that i don't lose the data in the highlights.
of course, like just about everything, this is situation dependent. experiment to know how your camera meter behaves in varying conditions. when shooting in the shade with a underlit/backlit subject, i'll overexpose...but that's about it.
-mike
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kevanrobitaille
Dec 8, 2006, 5:30 AM
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Ok great this all helps a lot. All books I have on photography are a few years old, and based soley on film photography, so at times I get confused trying to aply what I've learned over to digital. Thanks again.
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crleslie
Dec 8, 2006, 8:15 AM
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Your histogram is going to be one of your most important tools for determining correct exposure compensation. The trick is to "Expose Right" meaning to try and set your histogram as close to the right side as possible without blowing out the highlights. It is SAFER to step down when shooting in bright light, but if you end up increasing the exposure in post processing on your computer (assuming you shoot RAW which I highly recommend) then your shadows will have high noise levels. Also, RAW has a higher dynamic range since it is a 12 bit image (JPEG is 8 bit). If you have time, check out Luminous Landscapes (Google it) as there is a lot of good info about shooting digital. And in case you have ever shot film, digital Raw has close to the same dynamic range as slide film. Good Luck!
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dbrayack
Dec 8, 2006, 10:32 AM
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White balance is a real pain in the butt with DSLR, I use a gray card and the "PRE" white balance mode.
But I think I'm the only person in God's green earth who actually carries a gray card with me for DSLR climbing photos.
But my photos are generally ready to print straight off the camera.
I usually just set my exposure based on experience (usually -0.3-.1.0)
-Danno
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thespider
Dec 8, 2006, 4:32 PM
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Ok, a bit off topic, but when using a plastic bag over the body of a Nikon d200, do you mess up the light metering? The bag is a clear plastic, not like walmart or you favorite grocery bag. I think it can from some other equipment. The bag was not tight against the body, it was just draped over top and a hole for the lens was cut. Thanks!
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trenchdigger
Dec 8, 2006, 4:41 PM
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No, metering on an SLR is done through the lens.
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maldaly
Dec 8, 2006, 5:04 PM
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The best explaination I've seen for using WB and adjusting in the real works is found on Ken Rockwell's site. http://www.kenrockwell.com/tech/whitebalance.htm
If you dig around you'll find TONS more real world info on using your D70s.
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dbrayack
Dec 8, 2006, 8:03 PM
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I found that the auto white balance setting on the D70 was quite good, but with the D200, I found that I was having to do a good bit of tweaking to get the colors correct.
I prefer to shoot JPG since I can shoot a lot faster and more. Using the Gray card, life is simple.
I have a feeling that the newest firmware version of the D200 will update the "auto" whitebalance setting.
I would say that its a pain because its generally the only (technical) thing that I have to think about for a photoset.
Does anyone else just not the find auto white balance good enough? I tend to take a lot of photos; its nice to have them "ready to print/close" right off the chip.
You shoot Canon right? Hows the white balance settings on your homeboy?
(This post was edited by dbrayack on Dec 8, 2006, 8:04 PM)
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dbrayack
Dec 8, 2006, 8:31 PM
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You know, I came across that feature one day when I was playing around in PS. I bet you can write a PS action to do that to all of your images?
Great idea, I'm going to have to try that out.
-Dan
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