Horizons

[TarickTDS]

Ill tell you how i would do it.

Put your image in a larger scene so you have some room around it (most of the time you will need the space)

find some lines or objects in the scene that appear to run parallel and are level with the ground plane.

Draw your own lines over the top of these and extend them well past (seen in my image in red).

Now find an average of where the lines appear to intersect and that is roughly where your horizon line is (seen in my image in blue).

http://i238.photobucket.com/albums/ff214/ardentzealot/findinghorizonline.jpg

Good Luck,

Tarick :arteest:

[jkletzien]

Hmm, while Tarick is going down the right road....in this one it is gonna be a little more tricky as a lot of stuff isn't straight...most notably the ground plane (at least appears to ) slope up to the building. So the line it forms against the the building that is scribed to the left isn't parallel to the roof edge above it. Making where those 2 intersect, and Tarick has drawn, NOT the correct horizon line. This is confirmed by the sill of the window to the left...and its rather abrupt angle so close to the proposed horizon line.

Generally, I would also use the method Tarick describes....but you need to make sure the lines you're scribing are parallel. Or another method on architectural subjects is find some construction method employed in the photo that incorporates straight, level lines (brick, CMU's, Clapboard, windows) and find where the lines within slope neither up or down. In this photo for instance there is a patch of brick to the left hand side. At about 4-5 courses above the bench they flatten out....that is your physical horizon line - aka your camera height.

Not to be confused with your mechanical horizon line which by definition on a standard camera runs through the middle of your plate. Perhaps not too important a distinction here with this short of a building, but the more these seperate, tilting the picture plane (ie. you look up at a high rise) the greater your vertical convergence.

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