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Old Feb 27, 2005, 7:20 PM   #1
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A lot of my photos, especialy stuff for Ipix, have been coming out with some areas bleached out white and others are pitch black. This is probably a really basic issue, but I'd like some advice on how to avoid it.

I am using a Nikon Coolpix 5700 if that helps.

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Old Feb 27, 2005, 11:13 PM   #2
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Please post a few of your pics that display the problem, and let everyone know which camera and settings you are using.
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Old Feb 28, 2005, 7:13 AM   #3
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MrGaric wrote:
A lot of my photos, especialy stuff for Ipix, have been coming out with some areas bleached out white and others are pitch black. ...
Assuming the blocked (black) and blown out (white) areas are in the same photo, the root problem is that the dynamic range of digital cameras is limited. The more expensive cameras have a larger dynamic range, and some things can be done with your photo editor blending multiple shots. Since you are using IPIX, it isn't likely that you are much interested in the editor solution.

No digital camera comes anywhere close to the dynamic range of negative/reversal film.
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Old Feb 28, 2005, 8:07 AM   #4
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Here is an example....
I have mostly been shooting on full automatic. I don't have any of that software installed that shows my settings. If you can direct me to a place where I can download that I will get the settings from a random sampling.
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Old Feb 28, 2005, 8:54 AM   #5
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Here are the settings I used in this shot:

ExposureTime : 1/159.8Sec
FNumber : F4.5
ExposureProgram : Program Normal
ISOSpeedRatings : 100
ExposureBiasValue : EV0.0
MaxApertureValue : F2.8
MeteringMode : Division
LightSource : Unidentified
Flash : Not fired(Compulsory)
FocalLength : 8.90(mm)
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Old Feb 28, 2005, 10:34 AM   #6
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John Potter wrote:
Here is an example....
I fear that photography can't easily satisfy your requirements. Even the huge dynamic range of modern colour print film wouldn't cope with that scene. Lots of work in the darkroom would have helped, but it would been very difficult.

However, digital photography does offer a solution, as Bill Drew has said. It costs you nothing to take lots of shots with different exposures, and combine them later on your computer. Your digital camera may well allow you to take 5 'bracketed' shots with different exposures. The scene you showed us would require a very wide range of exposure.

Unfortunately you'll have to become a computer-person with time to spare in order to combine them into the perfect image.

You could also consider buying a big flashgun to light up the interior.

Good luck!

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Old Feb 28, 2005, 1:25 PM   #7
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I think much of the problem is location specific.

style="BACKGROUND-COLOR: #000000"As the guys before have mentioned, every sort of optical capture and projector has a limited "contrast ratio" -- A contrast ratio is the ratio of the brightest bright to the darkest dark able to be perceived by the instrument. For example, the contrast ratio of standard TV is, I believe, about 10:1; film about 50:1, and the human eye about 100 (or 200 at the max) :1. Here's what that means practically: Let's say you have a night scene with a streelight glowing on Humphrey Bogart, who'se standing in his trenchoat and fedora and smoking a cigarette. With the light just from the streelamp (or maybe an artificial moon), there's not a whole lot of light reflecting off of Bogey. But there is quite a bit of light being emitted from the streetlamp. Let's say the streetlight is producing 50 footcandles of light (just a random number). If we were shooting the thing for TV, there would have to be at least 5 footcandles of light reflecting off of Bogey. If not, then, to see Bogey's face, the TV camera would have to open its iris to let in more light. We could see Bogey's face, but then we'd loose all of the detail in the streetlight (It would appear "blown out"). If we didn't open the iris, the streetlight would appear to be properly exposed (you'd see all it's detail) but Bogey's face would just be a black blob and shadow.

style="BACKGROUND-COLOR: #000000"Now, when you go to film, because film has a better contrast ratio, you only need 1 footcandle of light to see detail on Bogey's face without blowing out the streetlight. There can be bigger gaps of contrast between light and dark, and the medium can reproduce them equally well. (Now you see why Film noir looks so much better on FILM and just doesn't reproduce quite as nicely on video.) If we were just looking at Bogey on the set, we would still be able to see his face if there were only 1/2 a footcandle reflecting off his face. Ironically, new LCD HD TVs and projectors have contrast ratios of 2000:1 or more, but that does no good, since even though the TV may be able to produce that much contrast, the human eye can't perceive it! Ha-- just one more way that impressive tech specs can be used to oversell products.

style="BACKGROUND-COLOR: #000000"So that's what's happening in this photo. Part of your shot is outdoors-- where there is a LOT of light and indoors with shadows, where there's NO light. (Sometimes hard to perceive the difference between indoor and outdoor lighting, but that's because we have really good "auto irises" in our eyes that adjust quite well!) SO your camera adjusted for the middle, looks like maybe underexposed the room highlights a little, but as a result lost both the highs (outside) and the lows (indoor shadows).

style="BACKGROUND-COLOR: #000000"The workaround is to do what Alan suggested -- "exposure bracketing" -- that means taking one shot exposed for outdoors (the indoors will be almost black) one exposed for the room (pretty much like you've got) and one exposed for the shadows (making the room look too bright) and then combine them in a photo editing software package. But other times, you want to accentuate highlight and shadow, and images perfectly exposed will look unnatural (see, for example, sunset pictures, where people properly expose for the foreground and then properly expose the sunset... often that can lead to a feeling of blandness or unnaturalness, IMO).

style="BACKGROUND-COLOR: #000000"So with that long winded explanation (maybe I can save this thread and link back to it some day) I hope that answers your question -- albeit unsatisfactorily.
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