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I\'ve got a real problem here...
Old 02-23-2004, 10:40 PM   #1 (permalink)
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...And I have some ideas about what I did, but I'm still racking my brain about it.

These shots are from this last Saturday - most of this set is crap, looks like this (straight out of the cam, only reduced in size to 25%). These two are one right behind the other, no changes to anything except focal length.

S2, 28-100, ISO 400, Fine mode jpegs at 3024

I did make the mistaken setting of Program AE on this set...A setting that I remedied while changing cards during her clothing change.

One thing that I don't understand is that the images looked great in the preview LCD...This just further cements my distrust of LCD's on cameras.

Lights used were the ever-popular 750w halogen worklights - two on a stand six feet high and eight feet away (immediately to the left of POV), one eight feet high and nine feet away four feet to the right of the camera POV.

So...Is it simply due to my setting error? Or something in addition?


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Re: I\'ve got a real problem here...
Old 02-23-2004, 11:23 PM   #2 (permalink)
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I might be mistaken but it looks to me more like the color temperature changed between the two shots. I noticed in the EXIF data that white balance was set to auto..

Hope this helps.

Israel
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Re: I\'ve got a real problem here...
Old 02-23-2004, 11:32 PM   #3 (permalink)
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Yes, Auto WB was another of the mistaken settings that I remedied AFTER this set.

I guess I don't understand why that would change in less than two seconds...Maybe because it's AUTO...And not locked in...

Thanks Israel
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Re: I\'ve got a real problem here...
Old 02-23-2004, 11:53 PM   #4 (permalink)
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My theory is that when you zoom in you end up with less to sample from so it would be more precise. It's just my theory so it could be WAY off base.. My understanding is that AUTO white balance will resample with each shot.

This is one of those reasons I like to shoot in RAW instead of JPG. I shoot in a lot of different environments and sometimes I change settings without realizing it.

Later,
Israel
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Re: I\'ve got a real problem here...
Old 02-24-2004, 02:20 AM   #5 (permalink)
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Auto White balance is calculated with EVERY shot which will give you a different setting EVERY TIME. Usually though you're focusing on an Eye so you don't get too much variation depending on your zoom. Shooting RAW or JPG will make absolutely no difference whatsoever!
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Re: I\'ve got a real problem here...
Old 02-24-2004, 02:27 AM   #6 (permalink)
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Strange shots Jon. Looks like your White Balance went south and your exposure was low. Other than having your camera focus with pinpoint accuracy on the bright spot in her eye, I can't see how the setting would have hit what it did. And why your exposure was toast is totally beyond me today. Even the second shot is a bit under. Is your LCD brightness tunred up too high?
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Re: I\'ve got a real problem here...
Old 02-24-2004, 10:12 AM   #7 (permalink)
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To clarify, the reason I shoot RAW instead of JPG is that it is a lot easier to fix white balance, exposure, and a few other things in RAW. Sometimes things go wrong and it's nice to have something to fall back on.

Since I've never seen it in print, I don't know for sure if white balance is measured throughout the scene, the focus bracket area, or according to exposure metering mode (i.e. spot, center, or matrix).


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Israel
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Re: I\'ve got a real problem here...
Old 02-24-2004, 10:47 AM   #8 (permalink)
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Ah yes, facts they all are! And that's a fine question about the white balance. I don't know! Hang on while I investigate.....

I dunno, Phil Askey at dpreview.com states in a Glossary Article that the cameras look at the Overall colour of an image (he used the Canadian and European colour!, that's weird!). As for specific models, maybe check the manuals. It would be good to know if you're going to try for auto mode.
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What you\'ve got...
Old 02-24-2004, 05:39 PM   #9 (permalink)
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Jon are a couple images underexposed by no less than 2.5 stops. The darker image is closer to 4 stops down - and as everyone has pointed out - you have a shift in your white balance. Why did this happen? Because of the zoom. The raster of the image shifts because the information pool shifted with the amount of area realized by the sensor. Look at it this way: If you have an area 1/4 of the field that is white the sensor in auto balance will try and neutralize that data to that formula, change the magnification (zoom in or out) and either enlarge or reduce the amount of white area, the formula will readjust neutralization. In the first image you have more of her blouse showing, but you also have more of the hay, her body, and the ambiance bouncing off all of the darker zones. In the second, you pushed the lens in and although we see less of the shirt, there is more of the area covered by that white blouse - thus more area for the sensor to try and neutralize.

In low light or tight light situations, try and fill the lens with a card, a gray card, and let the sensor see 100% of what it is trying to register. You take into consideration the value and the ambience, nothing more and nothing less, the two most important parts of what you are about to shoot. Save this custom white balance and shoot under that setting, no matter what magnification - if you are at f4 and your model stays against that hay, then whether you shoot at 80mm 50mm or 32mm, you keep the f stop at 4 with that custom white balance.



Here is a fixed version of your shot with the original histogram [left] and the compensating histogram [right]. Notice how all of your information is in the lower 60% of the value range, the bottom 6 f stops. I had to adjust this image by almost 5 stops to pull it back into value - 4 for the brightness and then another .5 to 1 stops in individual channels for color density. You then can see the spread of the data to the new histogram and see full exposure.

SUGGESTION: Do not use the LCD screen image for value, use it for composition and lighting, always look at your histogram to make sure you are getting the information. If you shoot a shot and look at the data graphic and it looks like the histogram on the left, you are sooooo underexposed, you need to open up because you are missing information.

Hope this helps.

Robert
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Re: What you\'ve got...
Old 02-24-2004, 08:58 PM   #10 (permalink)
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Hi Dave...Thank you!

The LCD is set for brightness wherever the factory set it...I don't trust it, so I don't use it. It appears that I should use it more often, and differently!


Hi Robert...Thank you!

You have confirmed a suspicion (well, everyone that replied confirmed) about the WB.

And YOU counseled me not long ago about locking the WB...Which I did heed, but not until AFTER I shot this set [img]/ubbthreads/images/graemlins/crazy.gif[/img] .

Another error that I clearly made was not locking the Aperture in...Letting the camera do it all (a sloppy oversight made in haste to get going on my part).

And, I had totally forgotten about the histogram review...Lesson learned there, certainly.

So here's another question, is the preferred ISO setting less than 400? I had thoughts about that as well...Perhaps I should have set down to 200...

Thanks to all of you that have replied!

And, just to show that I CAN take a good photo of a person once in a while (LOL), here's a snapshot from the next set that while having its own issues, isn't completely horrible.

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