Old 09-21-2009, 07:26 PM   #1
NSFan14
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Default Horizon Unlevel? Can I get your help?

Hello Folks,
I have a couple photos that got knocked for Horizon Unlevel. Could ya'll please help me on these shots?


The pole to the right is lined up...Which way should I go with this?
http://www.railpictures.net/viewreje...key=1050334820

Also, I realize this shot got knocked for being dark...But I need to get this Horizon unlevel stuff down.
http://www.railpictures.net/viewreje...d=733519&key=0

Thanks in advance!
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Old 09-21-2009, 07:33 PM   #2
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Originally Posted by NSFan14 View Post
The pole to the right is lined up...Which way should I go with this?
http://www.railpictures.net/viewreje...key=1050334820
Yeah, but everything else, especially things on the left side, is leaning to the right...lots of wide-angle distortion going on in that shot.
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Old 09-21-2009, 07:39 PM   #3
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Yeah, but everything else, especially things on the left side, is leaning to the right...lots of wide-angle distortion going on in that shot.
So, What your saying is the shot will never be fixed, Correct?
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Old 09-21-2009, 07:49 PM   #4
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Both are leaning to the right. They can defintely be fixed.
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Old 09-21-2009, 09:16 PM   #5
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Use something vertical near the center of the frame as guide. If it were me, I'd use the sides of the locomotive cabs.
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Old 09-22-2009, 02:33 AM   #6
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Alex...play with it a little bit. Try going counter clockwise.
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Old 09-22-2009, 02:34 AM   #7
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Default Alex...

I'm taking a guess at the lens you were using in that shot, by chance is it the old 18-55 non VR that came as a kit with the D40?

http://www.dpreview.com/lensreviews/..._n15/page3.asp

Quote:
As usual distortion is most pronounced at wideangle, with a rather pronounced 2.2% barrel at 18mm. The observed distortion pattern is relatively simple, with little recorrection towards the corners, so it should be reasonably easy to correct in software if desired.
This is the VR version that came with the D60 and later, but I imagine that the overall optics are rather similar. In other words, you should expect this level of distortion at wide angle. If you shoot in RAW and have the right software you should be able to remove it.

As stated, though, you need to rotate it to the left regardless of the distortion.

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Old 09-22-2009, 02:38 AM   #8
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If you shoot in RAW and have the right software you should be able to remove it.
Just to clarify a bit...you don't need a RAW image to fix distortion. A JPG or TIF can easily be de-distortified.
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Old 09-22-2009, 03:44 AM   #9
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Quote:
Originally Posted by Carl Becker View Post
http://www.dpreview.com/lensreviews/..._n15/page3.asp



This is the VR version that came with the D60 and later, but I imagine that the overall optics are rather similar. In other words, you should expect this level of distortion at wide angle.
Carl, this is confusing and inaccurate. Well, one leads to the other, no?

There are two kinds of distortion. One kind is a problem of lens performance or design, such as the barrel distortion referenced in your quote. This is a flaw of the lens and is something that can sometimes be corrected in software.

The problem here, at least as I see it, is not barrel (or pincushion) distortion but rather perspective distortion. Perspective distortion would occur even with a flawless lens as it is a basic issue of lens design and use. If one takes a standard design lens and points it at a subject with vertical lines and the camera is not perpendicular to those lines, they will bow in or bow out. Usually in for rail photographer because we usually have stuff like buildings rising above us.

The solution to this is not to get a better lens but rather a) to get a different lens, a "tilt-shift" lens (well, it is the shift part that deals with this), or b) to correct for the perspective distortion in post processing. Or c) to simply leave in the perspective distortion, which is quite commonly done also (albeit making sure the center of the image has vertical lines, which makes it "level"). Perhaps c) is the most common approach.

The OP may have a lens with some barrel distortion but that is not the issue being discussed here.

PS: the use of the word "distortion" in both of these contexts is in my view unfortunate, as some types of distortion are, for lack of a better term, bad, while perspective distortion is not bad in the sense that it is not caused by an imperfection in the lens.
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