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View Full Version : Decompensating Exposure Compensation?




Over Achiever
Feb 1, 2006, 09:54 PM
My 3 year old nephew was playing around with my camera last night and I didn't notice that he somehow set the EV to +1. I was wondering why the pictures I was taking this morning were so bright, but I didn't think much about it until I had to leave the site.

Is there a way in photoshop to turn down the EV by exactly -1? I know there will be some clipping of the bright highlights, but at least the pictures will look natural. We had a quick snowfall last night, and the temperatures stayed around 30-32 so it was the sticky type snow that makes all the trees glisten with white ... oh so very pretty.

Anyway, how should I go about adjusting the exposure after the fact?

Thanks,
OA

PS Oh, these pictures were taken with the Lumix FX-9, so they're JPEG, not RAW image files.



whocares
Feb 2, 2006, 12:07 PM
Simple answer is yes, I guess. There must be some way to calibrate the lightness or levels to exactly -1EV, but don't ask me how!

I thought I'd point out 2 other points though:
1. it's possible, albeit highly unlikely, that the +1EV screwed up your matrix metering a bit; and
2. the overexposure will have caused your highlights to burn out and saturate the CCD. This really messes up colours in the highlights.

The bottom line here is: you may not wan't to get that exact -1EV compensation. Maybe play around and see what makes the pics look best. You can still batch process if you need too.


My (un-educated) 2¢.

ChrisA
Feb 2, 2006, 02:26 PM
My 3 year old nephew was playing around with my camera last night and I didn't notice that he somehow set the EV to +1.

If all the pictures were taken in the snow on a bright day +1 may be about the correct adjectment. Typically a automatic camera will try and make the snow low light grey. a +1 setting will make it look white. I'd simply do what I do to every image. Go in, look at the histrogram and adjust "levels" to make it "look right". You might even be lucky and he did you a favor

The worst case is the highlites are "blown out" and you will have areas of wite with no details in them. But the shadow areas will actually look beter.

whocares
Feb 2, 2006, 02:59 PM
If all the pictures were taken in the snow on a bright day +1 may be about the correct adjectment. Typically a automatic camera will try and make the snow low light grey.

Nope! Good matrix meters know that anything above LV16 can't be light grey and shouldn't be exposed as light grey - it just gets ignored (or exposed as white if it covers the whole frame). Matrix meters expose snow as snow, ie white ;)

Of course, if the camera is set to center-weighted then you're completely right.


But I agree on jutt playing with curves to correct exposure.

The Past
Feb 2, 2006, 04:09 PM
Wonder if you have looked at this:

http://powerretouche.com/Exposure_plugin_introduction.htm

I have used this in the past, with mixed results.