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Old 01-24-2015, 03:14 AM   #14
Noct Foamer
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Join Date: Sep 2008
Location: South Dakota
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Quote:
Originally Posted by JRMDC View Post
1. Speaking of ice, as icicles are governed by gravity, they will drip vertically. They don't have precise linear shapes, so it's tricky, but they can serve as a guide.

2. We really should eliminate the use of the term "level" as the term "plumb" conveys the issue much more precisely - too many horizontal lines that aren't level to the frame when an image is plumb.

1. I originally bought a 4x5 to photo abandoned buildings, and ice formations/frozen waterfalls. It's true that the icicles form vertically, mostly. Where I live that's not always reliable though. If they formed in calm conditions or out of the wind, you're home free. I've seen icicles exposed to the wind that twist in several directions, as the wind changed. With the "reliable" icicles, I would line up a grid line on my ground glass (4x5) with the center line of an icicle, to avoid error caused by any taper on the side. Icicles are actually conical after all.

2. You got me thinking, and that's what I like about forums. I think "level" has to do with the X axis, and "plumb" has to do with Y axis. I think you are on to something though when you suggest when people say "level," they might really be meaning "plumb." As I said, there's very little in nature that is level, but a man made object like a dash nine will be plumb. Since a photo is 2D, and level & plumb are locked together, maybe I'm thinking too hard here. I'm heading back out west tomorrow night to chase some more trains, but I think when I'm home on Sunday I just might hang a plumb line from my basement ceiling, and then stretch one horizontally, and see just how accurate that digital level in my D800E is! Hopefully I'm not "suprised." I don't want to have to go back to using the torpedo.

And another thought on above photo. The large icicles seem to be out of the wind, and the centerlines of them should be fairly plumb. However, with many wide angle lenses you do start to get some barrel distortion on the edge of the frame. Trees don't always grow straight up--depends on prevailing wind (if any) and they tend to grow towards the average direction of the sun. I have found that individual corn stalks in a tight field tend to grow pretty straight up though.


Kent in SD

Last edited by Noct Foamer; 01-24-2015 at 03:18 AM.
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